This issue features Photobiomodulation (PBM)

Transcription

1 The Official Journal of the Academy of Laser Dentistry 2009 Vol. 17 No. 3 This issue features Photobiomodulation (PBM) Dr. Gerald Ross and Ms. Alana Ross explain how PBM is utilized in many dental procedures Dr. Lawrence Kotlow demonstrates how PBM is used in his pediatric dental practice Dr. Steven Parker demonstrates the use of a PBM laser for photodynamic antimicrobial chemotherapy Dr. Nelson Marquina and Dr. Fred Stalley provide a clinical study about the effects of PBM in orthodontic treatment A Tribute to Professor Endre Mester, the Father of Photobiomodulation Research Abstracts: The Effect of Low-Level Laser Therapy on Growth Factors Involved in Wound Healing Academy of Laser Dentistry 3300 University Drive, Suite 704 Coral Springs, FL 33065

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3 Journal of Laser Dentistry The official journal of the Academy of Laser Dentistry Editor-in-Chief Donald J. Coluzzi, DDS Portola Valley, CA Managing Editor Gail S. Siminovsky, CAE, Executive Director Coral Springs, FL Consulting Editor John G. Sulewski, MA Huntington Woods, MI Associate Editors Craig Gimbel, DDS, Denville, NJ Alan J. Goldstein, DMD, New York, NY Peter Pang, DDS, Sonoma, CA Donald E. Patthoff, DDS, Martinsburg, WV Steven P.A. Parker, BDS, LDS RCS, MFGDP, Harrogate, United Kingdom Peter Rechmann, Prof. Dr. med. dent., San Francisco, CA David Roshkind, DMD, Gainesville, FL Wayne Selting, DDS, Colorado Springs, CO Michael D. Swick, DMD, Conneaut Lake, PA Publisher Max G. Moses Member Media 1844 N. Larrabee Chicago, IL Fax: Design and Layout Diva Design 2616 Missum Pointe San Marcos, TX Fax Editorial Office 3300 University Drive, Suite 704 Coral Springs, FL Fax The Academy of Laser Dentistry is a not-for-profit organization qualifying under Section 501(c)(3) of the Internal Revenue Code. The Academy of Laser Dentistry is an international professional membership association of dental practitioners and supporting organizations dedicated to improving the health and well-being of patients through the proper use of laser technology. The Academy is dedicated to the advancement of knowledge, research and education and to the exchange of information relative to the art and science of the use of lasers in dentistry. The Academy endorses the Curriculum Guidelines and Standards for Dental Laser Education. Copyright 2009 Academy of Laser Dentistry. TABLE OF CONTENTS EDITOR S VIEW More Adventures with Lasers in Dentistry Donald J. Coluzzi, DDS COVER FEATURE CLINICAL REVIEW AND CASE REPORTS Photobiomodulation: An Invaluable Tool for All Dental Specialties..117 Gerald Ross, DDS and Alana Ross, BScH, Tottenham, Ontario, Canada COVER FEATURE CLINICAL REVIEW AND CASE REPORTS Photobiomodulating Lasers and Children s Dental Care Lawrence Kotlow, DDS, Albany, New York C OVER FEATURE CLINICAL REVIEW AND CASE REPORTS Photodynamic Antimicrobial Chemotherapy in the General Dental Practice Steven Parker, BDS, LDS RCS, MFGDP, MALD, Harrogate, United Kingdom COVER FEATURE CLIN ICAL RESEARCH Biostimulation Effects of Superpulsed, High-Intensity, Low-Average Power Laser Application on the Timing of Orthodontic Aligner Sequencing of the Invisalign System Nelson Marquina, MSc, PhD, DC, Richmond, Virginia; Fred Stalley, DDS, Redondo Beach, California TRI B UTE Professor Endre Mester, the Father of Photobiomodulation Professor Lajos Gáspár, DDS, PhD, Budapest, Hungary RESEARCH ABSTRACTS The Effect of Low-Level Laser Therapy on Growth Factors Involved in Wound Healing The Journal of Laser Dentistry The mission of the Journal of Laser Dentistry is to provide a professional journal that helps to fulfill the goal of information dissemination by the Academy of Laser Dentistry. The purpose of the Journal of Laser Dentistry is to present information about the use of lasers in dentistry. All articles are peer-reviewed. Issues include manuscripts on current indications for uses of lasers for dental applications, clinical case studies, reviews of topics relevant to laser dentistry, research articles, clinical studies, research abstracts detailing the scientific basis for the safety and efficacy of the devices, and articles about future and experimental procedures. In addition, featured columnists offer clinical insights, and editorials describe personal viewpoints.

4 Journal of Laser Dentistry: Guidelines for Authors The Academy of Laser Dentistry Welcomes Your Articles for Submission The Journal of Laser Dentistry publishes articles pertaining to the art, science, and practice of laser dentistry. Articles may be scientific and clinical in nature discussing new techniques, research, and programs, or may be applications-oriented describing specific problems and solutions. While lasers are our preferred orientation, other high-technology articles, as well as insights into marketing, practice management, regulation, and other aspects of dentistry that may be of interest to the dental profession, may be appropriate. All articles are peer-reviewed prior to acceptance, modification, or rejection. These guidelines are designed to help potential authors in writing and submitting manuscripts to the Journal of Laser Dentistry, the official publication of the Academy of Laser Dentistry (ALD). Please follow these instructions carefully to expedite review and processing of your submission. Manuscripts that do not adhere to these instructions will not be accepted for consideration. The Academy of Laser Dentistry and the editors and publisher of the Journal of Laser Dentistry endorse the Uniform Requirements for Manuscripts Submitted to Biomedical Journals ( The Journal reserves the right to revise or rescind these guidelines. Authors are advised to read the more comprehensive Guidelines for Authors and required forms available by mail or online at press/index.cfm. Manuscript Eligibility Submitted manuscripts must be written clearly and concisely in American English and appropriate for a scholarly journal. Write in active voice and use declarative sentences. Manuscripts will be considered for publication on the condition that they have been submitted exclusively to the Journal, and have not been published or submitted for publication in any part or form in another publication of any type, professional or lay, or in any language elsewhere, and with the understanding that they will not be reprinted without written consent from both the managing editor and the author. Permissions Direct quotations of 100 or more words, and illustrations, figures, tables, or other materials (or adaptations thereof) that have appeared in copyrighted material or are in press must be accompanied by written permission for their use in the Journal of Laser Dentistry from the copyright owner and original author along with complete information regarding source, including (as applicable) author(s), title of article, title of journal or book, year, volume number, issue number, pages. Photographs of identifiable persons must be accompanied by valid signed releases indicating informed consent. When informed consent has been obtained from any patient, identifiable or not, it should be noted in the manuscript. The appropriate Permission Letters must be submitted with the manuscript. Suggested template letters are available online. Copyright All manuscript rights shall be transferred to the Journal of Laser Dentistry upon submission. Upon submission of the manuscript, authors agree to submit a completed Copyright Transfer Agreement form, available online. If the manuscript is rejected for publication, all copyrights will be retained by the author(s). Commercialism ALD members are interested in learning about new products and service offerings, however ALD stresses that submitted manuscripts should be educational in nature. The emphasis is on scientific research and sound clinical and practical advice, rather than promotion of a specific product or service. Disclosure of Commercial Relationships According to the Academy s Conflict of Interest and Disclosure policy, manuscript authors and their institutions are expected to disclose any economic or financial support, as well as any personal, commercial, technological, academic, intellectual, professional, philosophical, political, or religious interests or potential bias that may be perceived as creating a conflict related to the material being published. Such conditions may include employment, consultancies, stock ownership or other equity interests, honoraria, stipends, paid expert testimony, patent ownership, patent licensing arrangements, royalties, or serving as an officer, director, or owner of a company whose products, or products of a competitor, are identified. Sources of support in the form of contracts, grants, equipment, drugs, material donations, clinical materials, special discounts or gifts, or other forms of support should be specified. The roles of the study or manuscript sponsor(s), if any, are to be described. Disclosure statements are printed at the end of the article following the author s biography. This policy is intended to alert the audience to any potential bias or conflict so that readers may form their own judgments about the material being presented. Disclosure forms are to be signed by each author. Manuscripts will not be reviewed without the Journal having this form on file. The Academy of Laser Dentistry also requires that authors disclose whether any product discussed in their manuscript is unlabeled for the use discussed or is investigational. The Disclosure Statement form is available online and must be submitted with the manuscript. Manuscript Types Submissions to the Journal should be limited to one of the types indicated below. Scientific / Technology / Clinical Review Case Reports and Clinical Case Studies Scientific / Clinical Research Randomized Clinical Trials Advances in Dental Products Trends Practice Management Guest Editorials and Essays Letters to the Editor Book Reviews Manuscript Preparation and Submission Format All submitted manuscripts should be double-spaced, using 12 pt. font size with at least 6 mm between lines. Submit manuscripts in Microsoft Word (.doc), using either the Windows or Macintosh platform. Manuscripts must be submitted electronically in this format. Hard copy-only submissions will not be accepted. Unacceptable Formats The following submission formats are unacceptable and will be returned: Manuscripts submitted in desktop publishing software PowerPoint presentations Any text files with embedded images Images in lower than the minimum prescribed resolution. Manuscript Components Title Page The title page of the manuscript should include a concise and informative title of the article; the first name, middle initial(s), and last name of each author, along with the academic degree(s), professional title(s), and the name and location (city, state, zip code) of current institutional affiliation(s) and department(s). Authors who are private practitioners should identify their location (city, state, and country). Include all information in the title that will make

5 electronic retrieval of the article sensitive and specific. Titles of case studies should include the laser wavelength(s) and type(s) utilized for treatment (for example, 810-nm GaAlAs diode ). Identify the complete address, business and home telephone numbers, fax number, address, and Web site address (if any) for all authors. Identify one author as the corresponding author. Unless requested otherwise, the address is published in the Journal. Abstract A self-standing summary of the text of up to 250 words should precede the introduction. It should provide an accurate summary of the most significant points and be representative of the entire article s content. Provide the context or background for the article, basic procedures, main findings and conclusions. Emphasize new or important aspects. Do not use abbreviations (other than standard units of measurement) or references in the abstract. Author(s) Biography Provide a brief, current biographical sketch of each author that includes professional education and professional affiliations. For authors who hold teaching positions, include the title, department, and school. For authors who are in federal service, include rank or title and station. References References are to be cited in the text by number in order of appearance, with the number appearing either as a superscript or in brackets. The reference list should appear at the end of the manuscript with references in order of first appearance in the text of the manuscript. The reference list must be typed double-spaced on a separate page and numbered in the same sequence as the reference citations appear in the text. Prior to submission, all references are to be properly prepared in the correct format, checked for completeness, carefully verified against their original documents, and checked for accurate correspondence between references cited in the text and listed in the References section. For journal citations, include surnames and all initials of all authors, complete title of article, name of journal (abbreviated according to the U.S. National Library of Medicine ( lpabbrev.html), year of publication, volume, issue number, and complete inclusive page numbers. If abstracts are cited, add the abstract number after the page number. For book citations, specify surnames and initials of all authors, chapter number and title (if applicable), editors surnames and initials, book title, volume number (if applicable), edition number (if applicable), city and full name of publisher, year of publication, and inclusive page numbers of citation. For government publications or bulletins, identify the author(s) (if given); title; department, bureau, agency, or office; the publication series, report, or monograph number; location of publisher; publisher; year of publication; and inclusive page numbers. For articles published online but not yet in print, cite with the paper s Digital Object Identifier (DOI) added to the end of the reference. For Web citations, list the authors and titles if known, then the URL and date it was accessed. For presentations, list the authors, title of presentation, indication that the reference is a lecture, name of conference or presentation venue, date, and location. Illustration Captions and Legends All illustrations must be accompanied by individual explanatory captions which should be typed double-spaced on a separate page with Arabic numerals corresponding to their respective illustration. Tables Tables must be typewritten doublespaced, including column heads, data, and footnotes, and submitted on separate pages. The tables are to be cited in the text and numbered consecutively in Arabic numerals in the order of their appearance in the text. Provide a concise title for each table that highlights the key result. Illustrations Illustrations include photographs, radiographs, micrographs, charts, graphs, and maps. Each should be numbered and cited in the text in the order of appearance and be accompanied by explanatory captions. Do not embed figures within the manuscript text. Each figure and table should be no larger than 8-1/2 x 11 inches. Digital files must measure at Illustration Type least 5 inches (127 mm) in width. The image must be submitted in the size it will be printed, or larger. Illustrations are to augment, not repeat, material in the text. Graphs must not repeat data presented in tables. Clinical photographs must comply with ALD s Guidelines for Clinical Photography, available online. Authors are to certify in a cover letter that digitized illustrations accurately represent the original data, condition, or image and are not electronically edited. Publisher and Copyright Holder The Journal of Laser Dentistry is published by Max G. Moses, Member Media, 1844 N. Larrabee, Chicago, IL 60614, Telephone: (312) ; Fax: (312) The Journal of Laser Dentistry is copyrighted by The Academy of Laser Dentistry, 3300 University Drive, Suite 704, Coral Springs, FL 33065, Telephone: (954) ; Fax: (954) Articles, Questions, Ideas Questions about clinical cases, scientific research, or ideas for other articles may be directed to Donald J. Coluzzi, Editor-in- Chief, by don@laser-dentistry.com. Submission of Files by Send your completed files by (files up to 10 MB are acceptable). If files are larger than 10 MB, they may be compressed or sent as more than one file, with appropriate labels. Files should be submitted to: Donald J. Coluzzi, Editor-in-Chief, by don@laser-dentistry.com. By Federal Express or Other Insured Courier: If using a courier, please send the file as a CD-ROM, include a hard copy of your manuscript and also send a verification by to Gail Siminovsky (laserexec@laserdentistry.org). Gail Siminovsky Academy of Laser Dentistry 3300 University Drive, Suite 704 Coral Springs, FL Phone: (954) Summary of Illustration Types and Specifications Definition and Examples Preferred Format Required Resolution Line Art and Black and white graphic with no EPS or JPG 1200 DPI Vector Graphics shading (e.g., graphs, charts, maps) Halftone Art Combination Art Photographs, drawings, or painting with fine shading (e.g., radiographs, micrographs with scale bars, intraoral photographs) Combination of halftone and line art (e.g., halftones containing line drawing, extensive lettering, color diagrams) TIFF or JPG 300 DPI (black & white) 600 DPI (color) EPS or JPG 1200 DPI

6 Editorial Policy The Journal of Laser Dentistry is devoted to providing the Academy and its members with comprehensive clinical, didactic and research information about the safe and effective uses of lasers in dentistry. All statements of opinions and/or fact are published under the authority of the authors, including editorials and articles. The Academy is not responsible for the opinions expressed by the writers, editors or advertisers. The views are not to be accepted as the views of the Academy of Laser Dentistry unless such statements have been expressly adopted by the organization. Information on any research, clinical procedures or products may be obtained from the author. Comments concerning content may be directed to the Academy s main office by to laserexec@laserdentistry.org Submissions We encourage prospective authors to follow JLD s Guidelines for Authors before submitting manuscripts. To obtain a copy, please go to our Web site Please send manuscripts by to the Editor at don@laser-dentistry.com. Disclosure Policy of Contributing Authors Commercial Relationships According to the Academy s Conflict of Interest and Disclosure policy, authors of manuscripts for JLD are expected to disclose any economic support, personal interests, or potential bias that may be perceived as creating a conflict related to the material being published. Disclosure statements are printed at the end of the article following the author s biography. This policy is intended to alert the audience to any potential bias or conflict so that readers may form their own judgments about the material being presented. Disclosure Statement for the Academy of Laser Dentistry The Academy of Laser Dentistry has no financial interest in any manufacturers or vendors of dental supplies. Reprint Permission Policy Written permission must be obtained to duplicate and/or distribute any portion of the Journal of Laser Dentistry. Reprints may be obtained directly from the Academy of Laser Dentistry provided that any appropriate fee is paid. Copyright 2009 Academy of Laser Dentistry. All rights reserved unless other ownership is indicated. If any omission or infringement of copyright has occurred through oversight, upon notification amendment will be made in a future issue. No part of this publication may be reproduced or transmitted in any form or by any means, individually or by any means, without permission from the copyright holder. The Journal of the Academy of Laser Dentistry ISSN# JLD is published quarterly and mailed nonprofit standard mail to all ALD members. Issues are also mailed to new member prospects and dentists requesting information on lasers in dentistry. Advertising Information and Rates Display rates are available at and/or supplied upon request. Insertion orders and materials should be sent to Bill Spilman, Innovative Media Solutions, P.O. Box 399, Oneida, IL 61467, , fax: , bill@innovativemediasolutions.com. For a copy of JLD Advertising Guidelines go to guidelines.cfm. The cost for a classified ad in one issue is $50 for the first 25 words and $2.00 for each additional word beyond 25. ALD members receive a 20% discount. Payment must accompany ad copy and is payable to the Academy of Laser Dentistry in U.S. funds only. Classified advertising is not open to commercial enterprises. Companies are encouraged to contact Bill Spilman for information on display advertising specifications and rates. The Academy reserves the right to edit or refuse ads. Editor s Note on Advertising: The Journal of Laser Dentistry currently accepts advertisements for different dental laser educational programs. Not all dental laser educational courses are recognized by the Academy of Laser Dentistry. ALD as an independent professional dental organization is concerned that courses meet the stringent guidelines following professional standards of education. Readers are advised to verify with ALD whether or not specific courses are recognized by the Academy of Laser Dentistry in their use of the Curriculum Guidelines and Standards for Dental Laser Education.

7 More Adventures with Lasers in Dentistry Donald J. Coluzzi, DDS, Portola Valley, California J Laser Dent 2009;17(3): EDITOR S VIEW This issue of the Journal will continue to present articles from some of the presenters at the Academy s April th Annual Conference in Las Vegas. As mentioned previously, their manuscripts give those of us who were in attendance a chance to remember their discussions, and enable all of our members to read their topics. These articles offer us extensive details about using low-level lasers. To be clear, the term low-level laser refers to a device whose emission power is substantially below surgical lasers in other words, a low-level laser cannot produce coagulation, protein denaturation, vaporization, and/or ablation of dental tissue. Low-level lasers have been used in some branches of medical and veterinary offices for some time; in addition, some dental practitioners have employed a laser-based carious lesion detector, or a laser to cure composite resin. The term photobiomodulation (PBM) is generally substituted for low-level laser therapy. It more accurately describes the reported biologic effects of the coherent energy that is absorbed by cellular elements, resulting in stimulation of tissue-healing mechanisms. Another application of the use of low-level laser output is called photodynamic therapy (PDT), where a photosensitizing chemical is applied to tissue and is activated by laser energy, producing a singlet oxygen radical which can destroy adjacent cells. Certain tumors can be treated with this method. A dental development of this technique, termed photo-activated disinfection (PAD) or photodynamic antimicrobial chemotherapy (PACT), can be used to treat infections. Curiously, and perhaps expectedly, the availability of these devices varies according to geographic region. The U.S. Food and Drug Administration (FDA) has granted marketing clearances to a number of devices, although none of those clearances are specifically for dentistry, which should be considered off-label uses. The manufacturers and distributors generally sell to licensed practitioners of all the health sciences. A typical clearance might read: The device is used when heat is indicated for temporary increase in local blood circulation, temporary relief of minor muscle and joint aches, pains and stiffness and relaxation of muscles; for muscle spasms, minor pain and stiffness associated with arthritis (FDA 510(k) clearance K082727, October 1, 2008, MedX LPT 200 and MedX LPS 200 (OraLase) portable laser, MedX Health Corp., Mississauga, Ontario, Canada). There are seven authors in this section: Dr. Gerald Ross offers an overview of PBM for dental applications. Dr. Ross and his co-author, Alana Ross, have extensive experience providing education about this technology. Dr. Lawrence Kotlow writes about how PBM lasers are used in his pediatric dental practice, from the reduction of pain to the elimination of the gag reflex. Dr. Steven Parker s manuscript describes the use of PACT in his general dental practice to reduce bacteria with clinical case examples showing treatment of periodontal and peri-implant inflammation. Dr. Nelson Marquina and Dr. Fred Stalley illustrate the use of PBM in a study of patients undergoing a specific orthodontic treatment plan. These two authors are colleagues of Dr. Robert Gougaloff, one of the speakers in the PBM section of ALD's 2009 Las Vegas conference. As an added highlight, Professor Lajos Gáspár, an Academy member in Hungary, offers a short biographical sketch of Endre Mester, MD, DSc, who is internationally recognized as the father of PBM. Despite the possible confusion with the alphabet soup of the above acronyms, I hope that you, the reader, will have a good understanding of this use of laser energy. In addition, the Research Abstracts section offers several current summaries using PBM for wound healing and tissue repair. You will note the titles use various phrases, like low-level, low-power, and low-intensity to describe laser irradiation parameters. As usual, I hope you enjoy this issue. Please don t hesitate to contact me with your comments, or, better yet, your articles. AUTHOR BIOGRAPHY Dr. Donald Coluzzi, a 1970 graduate of the University of Southern California School of Dentistry, is an associate clinical professor in the Department of Preventive and Restorative Dental Sciences at the University of California San Francisco School of Dentistry. He is a charter member and past president of the Academy of Laser Dentistry, and is currently the Editor-in-Chief of the Journal of Laser Dentistry. He has used dental lasers since early He has Advanced Proficiency in Nd:YAG and Er:YAG laser wavelengths. He Coluzzi 115

8 EDITOR S VIEW is the 1999 recipient of the Leon Goldman Award for Clinical Excellence and the 2006 Distinguished Service Award from the Academy of Laser Dentistry, a Fellow of the American College of Dentists, and a Master of the Academy of Laser Dentistry. Dr. Coluzzi has presented about lasers worldwide, co-authored two books, and published several peerreviewed articles. Dr. Coluzzi may be contacted by at don@laser-dentistry.com. Disclosure: Dr. Coluzzi is a past and present presenter at various local, state, and national dental meetings. He has no financial interest in any company. Protection & Magnification Combined See what you ve been missing during laser procedures. S u p e r i o r Rudy Project Sports Frame Revolution Frame Titanium Frame V i s u a l i z a t i o n Middleton, WI Protection. Built-in laser protection in both the telescope and the carrier lenses (no clips or inserts required). Compatibility. Filter options support most soft tissue laser wavelengths. Power. Four magnification power options. Customized. Loupes are manufactured to your specific facial geometry, working distance and declination. Filters are available for the most popular laser wave lengths used in the dental industry including: nm nm 1064 nm nm nm 10,600 nm 116 Coluzzi

9 CLINICAL REVIEW AND CASE REPORTS Photobiomodulation: An Invaluable Tool for All Dental Specialties Gerald Ross, DDS, Alana Ross, BScH, Tottenham, Ontario, Canada J Laser Dent 2009;17(3): INTRODUCTION Although low-level lasers are being used successfully in many dental clinics, the wide range of applications is still largely unknown to many practitioners, especially dental specialists. In these fields, there is the potential to see the most definitive results of what laser therapy can do to improve clinical outcomes and patient satisfaction. Photobiomodulation (PBM), also commonly referred to as low-level laser therapy (LLLT) or cold laser therapy, uses light energy to elicit biological responses from the cell and normalize cell function. Numerous studies have shown that PBM affects the mitochondria of the cell, primarily cytochrome-c oxidase in the electron transfer chain and porphyrins on the cell membrane. 1-2 It has been proposed that when light photons are Figure 1: Summary of the primary mechanisms of photobiomodulation absorbed by these receptors, three events occur: stimulation of adenosine triphosphate (ATP) synthesis by activation of the electron transport chain; transient stimulation of reactive oxygen species, which increases the conversion of adenosine diphosphate (ADP) to ATP; and a temporary release of nitric oxide from its binding site on cytochrome-c oxidase. These factors contribute to the clinical effects seen with PBM, including tissue repair, relief of inflammation and pain, and repair of nerve damage. 3 Figure 1 depicts a flowchart showing these interactions. Studies have documented beneficial effects of PBM, such as stimulation of fibroblasts and osteoblasts, as well a reduction of the depolarization of nerve fibers. 4-6 From a clinical perspective, PBM offers dental practitioners a noninvasive and nonthermal treatment modality that can be used as an adjunct to traditional therapies or as a therapeutic tool on its own. 7 Examples of these clinical applications, which will be discussed below, include dental analgesia, treatment of dentin hypersensitivity, healing of soft tissue lesions, reduction of pain and swelling after surgical procedures, better integration of implants into bone, and faster movement of teeth during orthodontic procedures. Determining the Appropriate Dose Treatment dose is probably the most important variable in laser treatment. Dose is measured in joules per square centimeter (J/cm 2 ) and is a measure of the amount of energy that is conducted into the tissue. Clinical effects of the laser, such as wound healing, pain relief, or muscle relaxation, are all sensitive to different irradiances or doses. An example of this is the stimulation of fibroblasts; a dose of 5 J/cm 2 will stimulate the cellular activity of fibroblasts, whereas higher doses inhibit cell viability and proliferation. 8 Thus, for wound healing, the clinician should ideally use a dose lower than 5 J/cm 2. The biostimulatory and inhibitory effects of lasers are governed by the Arndt-Schultz Law, which indicates that weak stimuli will increase physiological processes and strong stimuli will inhibit physiological activity.a therapeutic window, which includes both biostimulatory and bioinhibitory effects, is evident and is the intended target for PBM treatments. A depiction of the law, based on Baxter, 9 is shown in Figure 2. Ross and Ross 117

10 CLINICAL REVIEW AND CASE REPORTS swelling following surgical extraction of the third molar and found that measurements of swelling were about 5 mm less and measurements of trismus (inter-incisal opening) were about 5 mm greater than in the placebo group on days 2 and In a meta-analysis of studies investigating pain within 24 hours of surgery, Bjordal et al. found that LLLT with red and infrared wavelengths is effective in reducing acute inflammatory pain after molar extraction. 13 Figure 2: Arndt-Schultz curve. The horizontal axis depicts an increasingly higher dose from left to right, and indicates that biostimulation occurs with relatively smaller doses when compared to the higher doses that cause bioinhibition Dry Socket Tunér and Hode describe the benefits of PBM in helping to prevent alveolitis after a tooth extraction. 14 The following case study illustrates PBM treatment for a painful dry socket. The importance of dose should always be kept in mind when using PBM; if the clinician is not achieving the anticipated response to laser treatment, the dose should be re-evaluated to ensure it is within the optimal range. Additionally, treatments may need to be modified over time to ensure the practitioner is achieving the ideal effect from the laser dose (pain relief vs. wound healing). Acute vs. Chronic Pain Treatment dose and duration will largely be governed by the status of the injury. PBM can effectively speed the resolution of acute inflammation and pain, conditions that should be treated frequently (daily). The reverse applies to chronic pain; treatments should be done using lower doses over a longer period of time (e.g., treat 2 to 3 times per week for 3 to 4 weeks). CLINICAL APPLICATIONS OF PHOTOBIOMODULATION IN DENTAL SPECIALTIES Oral Surgery Dental surgeons can utilize PBM in almost every facet of their practice. Many procedures a dental surgeon performs, especially extraction of molars, create an acute inflammatory response that can result in edema, bruising, and pain. Currently, the primary method of dealing with the pain and discomfort of the surgical procedures is prescription of pain analgesics, many of which carry side effects or decreased mental alertness. Studies have demonstrated that PBM in acute pain reduction compares well to standard nonsteroidal antiinflammatory drug (NSAID) treatment, with a better riskbenefit profile. 10 Healing is also accelerated by stimulation of fibroblasts and osteoblasts, which produce soft tissue and bone, respectively, as noted in an animal study conducted by Gerbi et al. 11 Post-Extraction Following any surgical extraction, laser irradiation is applied into the socket immediately after the surgery for reduction of pain and inflammation and then after suturing for soft tissue healing (Figure 3). Aras and Güngörmüş studied the effect of PBM on trismus and facial Oral Mucositis Oral mucositis, presenting as an open sore over the oral soft tissue, is a life-altering condition that is a side effect of chemotherapy and radiation therapy. Laser therapy has been investigated as a preventative application to mucositis and as a treatment modality for healing erupted sores, with positive results. 15 A 2006 study by Corti et al., using a light-emitting diode device with an emission of 645 ± 15 nm, demonstrated that PBM accelerated the healing rate of oral mucositis by 117% to 164%. 16 Often, oral mucositis can be so debilitating for patients that they cannot continue their cancer treatments, so a tool that can treat or Figure 3: Application of low-level laser energy into the socket immediately following extraction 118 Ross and Ross

11 CLINICAL REVIEW AND CASE REPORTS prevent the sores will have considerable clinical importance. Consultation with the oncologist should always be done prior to commencing laser treatments. Fractures and Orthognathic Surgery PBM accelerates healing of bone after fractures or orthognathic surgery through the stimulation of osteoblasts. A 2005 study in rats demonstrated that laser irradiation resulted in an increase in bone neoformation, with better quality bone on the irradiated groups when compared to the control group, who received no radiation. 11 Soft Tissue Lesions Soft tissue lesions, such as herpes simplex, denture sores, and angular cheilitis respond positively to lowlevel laser irradiation. Schindl and Neumann investigated the effect of LLLT on recurrent herpes simplex and demonstrated that 10 daily irradiations significantly lowered the incidence of local recurrence and is a beneficial treatment alternative to commonly used drugs such as acyclovir and famciclovir. 17 Further, the author has clinically observed that laser irradiation of herpes simplex decreases the incidence of lesion recurrence. Marei et al. examined the effect of laser irradiation on denture sores and noted that LLLT eased the pain caused by denture lesions, while at 4 weeks post-treatment the laserirradiated areas showed clinically superior healing, and histological epithelialization and vascularization of the lesion. 18 Tunér and Hode report successful treatment of angular chelitis with PBM, but warn of its recurrence if the fundamental cause is not dealt with. 19 It is advantageous to treat any soft tissue lesion in its most acute stage. For example, herpetic lesions are most susceptible to LLLT during their prodromal stage. Figure 4 demonstrates the treatment of a lesion on the lip using an 830-nm PBM device. Dental Infections For infections and edema, PBM has been reported to dilate lymphatic vessels and reduce the permeability of blood vessels. 20 Figure 5 demonstrates the application to the lymph nodes using a PBM device. Primary Tooth Restorations A variety of factors contribute to the analgesic effect produced by PBM which allows dental practitioners to perform many primary tooth restorations without anesthesia. Small animal studies show that laser irradiation promotes a release of endorphins and serotonin; inhibits the conduction of C fibers, the fibers that carry pulpal pain; and increases oxygenation and lymphatic drainage, which are responsible for pain relief after the first minutes of tissue irradiation. 6, Figure 4: LLLT treatment of a soft tissue lesion CASE STUDY: DRY SOCKET Treating Dentist: Dr. Gerald Ross A 45-year-old male patient had a lower first molar extracted. During the postoperative instructions, the patient (a smoker) was advised to avoid smoking cigarettes for a minimum of 2 days. The patient presented the following day with dry socket and admitted to smoking the previous evening. An 830-nm PBM device was used. The intraoral light guide was placed in the socket and the socket was irradiated until pain relief was felt by patient (in this case 48 J/cm 2 of energy was applied before the patient started to experience a reduction in discomfort). A dressing was placed into the socket and the patient was sent home without any pain medications. The patient returned the next day for a dressing change and the laser was applied into the socket using 4 J/cm 2 before application of the new dressing for stimulation of the epithelium in the socket. The patient did not require any additional treatments and the area healed in 7 days. CASE STUDY: ORAL MUCOSITIS Treating Dentist: Dr. Gerald Ross A 61-year-old female patient undergoing chemotherapy for terminal cancer presented with numerous sores over the inside of her mouth. The patient could not eat, drink, or swallow without extreme pain. Treatments (mouth rinses) assigned by the oncologist had no effect on healing of the sores. A visible red laser (660 nm) was applied intraorally overlapping throughout the mouth for 2 days in a row. When the patient came in on the second day, the pain was markedly decreased and she was able to eat soup. By the fourth day, she was able to eat normally. The patient passed away in the following month but no sores returned during that time. NOTE: Prior to laser treatment, the dentist contacted the oncologist who was willing to try any treatment that could work on the mucositis. Ross and Ross 119

12 CLINICAL REVIEW AND CASE REPORTS Figure 6: Promotion of analgesia via LLLT for primary tooth restorations Figure 5: Application of low-level laser to the submandibular lymph nodes Laser irradiation is applied to the apex of each root for analgesia and again after the tooth has been prepared for reduction of pain and inflammation, as shown in Figure 6. Distraction techniques are recommended to help the patient deal with the mental fears or anxiety surrounding the dental appointment. Dental analgesia does not seem to be as effective in permanent teeth because of the increased size and sensitivity of the dental pulp; however, it has been shown clinically to be effective for pain relief during crown cementations and decreased sensitivity during scaling appointments. Nausea and Gagging Application of the laser to the P6 (Pericard 6) acupuncture point on the wrist can decrease or eliminate the nausea and gagging some patients feel during impressiontaking or X-ray procedures. As shown in Figure 7, the P6 is located on the underside of the wrist, approximately 1 inch from the distal palmar crease (approximately the width of the distal thumb phalanx). 23 For patients who are extremely nauseous or anxious, application to three acupuncture points in the wrist can be effective; H7, LU9, and P6 are the parasympathetic calming points and stimulation of these points can be very effective in reducing anxiety. A 1998 report in the British Journal of Anaesthesia investigated the effectiveness of laser irradiation to the P6 acupuncture point on postoperative vomiting. In the laser stimulation group, the incidence of vomiting was significantly lower (25%) than in the placebo group (85%), and the patients were quite receptive to the painless procedure. 24 Uptake and Elimination of Anesthesia Based on the mechanisms of PBM therapy s ability to increase blood circulation, 4 the author has found that there is an increase in uptake and elimination of anesthesia. PBM is applied to the submandibular lymph nodes and the site of injection after the injection and upon completion of the dental appointment, for uptake and elimination, respectively. Implant Placement Three papers indicate that PBM can reduce inflammation following implant placement, help speed the integration of the implant into the bone, and improve the quality of the bone around the implant. A study using rabbits utilized Raman spectroscopy and electronic microscopy to investigate the effect of infrared light on the loading time of dental implants, and found Figure 7: A graphic diagram of three parasympathetic calming acupuncture points for reduction of nausea and gagging. Courtesy of Donald J. Coluzzi, DDS. Adapted from Atlas of acupuncture points. Point locations [Internet]. Published by [Cited 2009 Dec 28.] 39 p. Available from: Acupuncture_Points.pdf. a significantly greater amount of mature bone, a better distribution of bone, and more organization of bone after laser irradiation, when compared to the control group that received no laser irradiation. 25 Another study used rats to examine the effect of laser therapy on bone and demonstrated that the laser group had an abbreviated initial inflammatory response and a rapid stimulation of bone matrix formation at 15 and 45 days. 26 An earlier rabbit study showed that bone healing is improved and those authors concluded that it is possible to reduce the loading time of implants in the mandible of humans from 4 months to approximately 2 months and 24 days, and in the maxilla, from 6 months to 4 months and 6 days. 27 Orthodontics Orthodontic treatments are lengthy and often painful for many patients. As mentioned previously, Gerbi et al. have shown that PBM irradiation on bone increases osteoblastic proliferation, collagen deposition 120 Ross and Ross

13 CLINICAL REVIEW AND CASE REPORTS and bone neoformation when compared to non-irradiated bone. 11 A 2008 study investigating the effect of laser therapy on orthodontic movement showed that the velocity of canine movement was significantly higher in the laser-irradiated teeth compared to teeth that received no irradiation. In addition, the pain intensity was also at a lower level in the lased group throughout the entire retraction period. 28 Histological observations made during another study on rabbits showed that both osteoblasts and osteoclasts remained more active on the lased side which could account for the accelerated movement. 29 Finally, Turnhani et al. showed that a single application of LLLT reduced the pain at 6 and 30 hours after banding treatment. 30 Periodontics The use of PBM as a treatment modality in periodontics is effective, either as a treatment method on its own or as an adjunct to the increasingly popular surgical lasers. A recent study investigated the gingival inflammatory response and dental plaque reduction following scaling and root planing combined with PBM in 60 patients. The authors found a significant decrease in the clinical indices (plaque, gingival, and sulcular bleeding), which they thought could be beneficial in the treatment of chronic advanced periodontitis. 31 Periodontal Surgery Healing after periodontal surgery is often a lengthy and painful process. PBM has been shown to stimulate fibroblasts for faster regeneration of soft tissue, while providing analgesia and a modulation of the inflammatory chemicals that cause pain and discomfort. A 2006 study showed a statistically significant decrease in pocket depth at 21 and 28 days post-surgery. Moreover, the laser-treated wounds presented with factors suggestive of better healing, including color, contour, and mucosa healing when compared with non-laser treated area, which served as a control. 32 To further exemplify these positive responses, a study by Ozcelik et al. demonstrated that LLLT enhanced epithelialization and improved wound healing after gingivectomy and gingivoplasty operations. 33 Figure 8 shows an 830-nm PBM device being used to irradiate a closed incision. Endodontics PBM is effective for reducing pain and inflammation after endodontic treatments, for dentin hypersensitivity, and as a diagnostic tool for pulp hyperemia. 34 Figure 8: LLLT irradiation after flap surgery Figure 9: Flowchart for endodontic diagnosis Laser Therapy as a Diagnostic Tool Occasionally, a patient will present to a dental practitioner with excessive tooth pain, the source of which cannot be accurately identified. Traditional diagnostic methods such as thermal or electrical stimuli often do not show any indication of the problem, making the diagnosis and treatment stressful for both the patient and the doctor. As stated previously, PBM irradiation increases circulation, thus a patient with a hyperemic pulp will feel a sharp pain when the laser is applied to a tooth. 35 Figure 9 shows a diagnostic outline that could be used in endodontics. Dentin Hypersensitivity A study by Marsilio et al. demonstrated that LLLT treatment of dentin hypersensitivity in two different groups of patients was effective for 86% to 88% of all the participants. 36 Another study compared LLLT to topical fluoride varnish application for treatment of dentinal hypersensitivity and found that 86% of the laser irradiation group achieved absence of pain compared to 27% of the fluoride group. 37 Ross and Ross 121

14 CLINICAL REVIEW AND CASE REPORTS TMJ and Facial Pain When treating temporomandibular joint (TMJ) or facial pain, PBM is a useful tool to add to the therapeutic arsenal. From simple acute cases like facial pain after long appointments to chronic TMJ cases, laser therapy will help reduce pain and inflammation, and significantly resolve muscle trismus. In a systematic review of postoperative pain relief in patients after undergoing third molar extraction, a PBM irradiation was shown to be beneficial in reducing acute inflammatory pain. 13 In a clinical study of 74 patients complaining of TMJ pain, 64% were pain-free or had improvement in comfort after 12 PBM sessions over a six-week period. 38 Pinheiro and colleagues analyzed the effect of PBM on maxillofacial disorders by irradiating 141 female and 24 male patients twice a week for 6 weeks. At the end of the treatment 72% of patients were aymptomatic and 15% had improved considerably. 39 Neuropathic Pain Neuropathic facial pain is a debilitating condition for a patient that results in their living with excruciating pain or with a continuous dose of prescription analgesics. As stated above in the study by Bjordal et al., 13 PBM permits many patients to live a life free from discomfort or with less pain. CONCLUSION Although PBM has been available to health care professionals since the 1960s, low-level laser therapy did not really begin to gain popularity until the 1980s when controlled and randomized studies began to be published. In 2007, Karu reported that the effects of PBM are dependent on the initial redox status of a cell. If a cell is damaged, or in a reduced redox state, the cellular response to PBM will be stronger. Conversely, a cell which is at an optimal redox potential will have a weak or absent cellular response to PBM. 2 Thus, cells that are damaged will respond to PBM better than cells that are healthy and functioning normally. However, there are precautions all laser users should take and areas to avoid treating when using PBM. Specifically, those include avoiding exposure to the thyroid gland, to pregnant women, and to radiation therapy patients. 40 Also important to note is that the laser will be ineffective if the patient has had a steroid injection in the last six months. 41 All laser users should consult their laser manufacturer for any questions regarding contraindications and appropriate treatment doses, as well as for instructions about safety eyewear for everyone within the nominal hazard zone of the beam. Photobiomodulation is an evolving technology. With every passing day, more is being discovered about the mechanisms of laser therapy, doses, treatment locations, and diseases in which a laser will have an effect. At our hands is a tool that can reduce pain, stimulate wound healing, and modulate the inflammatory response. Photobiomodulation can be used effectively in dental specialties to better manage treatments that are often deemed painful by patients, without prescribing pharmaceuticals that often have a number of side effects. All healthcare professionals, including dentists and dental specialists, should further investigate photobiomodulation to enhance their clinical treatments and outcomes. CASE STUDY: TMJ PAIN Treating Dentist: Dr. Gerald Ross A 55-year-old patient presented with pain in the left temporomandibular joint and a limited ability to open the mouth. The computed tomography (CT) tomogram (R = right, SMV = submental vertex, L = left) showed degenerative joint disease (osteoarthritis) of the left TMJ with no disc present. Six applications of the laser were performed over a three-week period, with treatment applications to the joint, joint capsule, and the lateral pterygoid muscle. This treatment resulted in the patient being pain-free for the last two years and with the ability to open the mouth wider. 122 Ross and Ross

15 CLINICAL REVIEW AND CASE REPORTS CASE STUDY: NEUROPATHIC PAIN Treating Dentist: Dr. Gerald Ross A 61-year-old male patient presented with pain and felt it was coming from the lower left molar. The tooth was extracted and the socket healed uneventfully but the pain got worse. At that point, there were no other problems with teeth in that quadrant, however the pain was worsening and the patient was taking Tylenol No. 3 (30 mg) approximately 4 times per day, every day. Laser irradiation was applied to the trigeminal nerve, the molar site, and the trigeminal ganglion. After 1 application, the patient said he was no longer taking Tylenol No. 3 and took only 2 Advil at bedtime. Three days later a second application was done to the same site, and the patient reported as pain-free and no longer needing medication. The pain-free status has lasted for three months. AUTHOR BIOGRAPHIES Dr. Gerald Ross has been practicing dentistry for more than 30 years in Tottenham, Ontario. He has been using surgical and low-level lasers clinically since 1990 and has lectured extensively in Canada, the United States, and internationally. He holds Advanced Proficiency status from the Academy of Laser Dentistry and a fellowship from the American Society of Laser Medicine and Surgery. In 2008, Dr. Ross was asked to present a paper and chair the dental session at the World Association for Laser Therapy (WALT) meeting that was held in South Africa. He is currently a board member of the North American Association for Laser Therapy (NAALT) and is helping with numerous studies on photobiomodulation. Dr. Ross may be contacted by at ddsross@rogers.com. Alana Ross, BScH, graduated with an honors degree in Biomedical Science from the University of Guelph in Ontario, Canada. In 2004, Alana cofounded, and is currently the executive director of, Laser Light Canada, a company involved in the distribution of and education relating to low-level lasers and phototherapy equipment in North America. She has published numerous articles on low-level laser therapy and is presently overseeing several clinical studies. Currently, she is the chair of the NAALT 2010 Annual Conference committee, serves on the NAALT Board of Directors, and is a member of the NAALT membership committee. Disclosures: Dr. Ross is the president of Laser Light Canada, a company which is involved in the distribution and education related to low-level lasers in dentistry. Ms. Ross is the executive director of that company. None of the manufacturers of the instruments sold by Laser Light Canada had any input into this article. REFERENCES 1. Tafur J, Mills PJ. Low-intensity light therapy: Exploring the role of redox mechanisms. Photomed Laser Surg 2008;26(4): Karu TI. Low-power laser therapy. Chapter 48 in: Vo-Dinh T, editor. Biomedical photonics handbook. Boca Raton, Fla.: CRC Press, 2003: Hamblin MR, Demidove TN. Mechanisms of low level light therapy. In: Hamblin MR, Waynant RW, Anders J, editors. Mechanisms for Low-Light Therapy, January 22 and 24, 2006, San Jose, Calif. Proc. SPIE Bellingham, Wash.: SPIE The International Society for Optical Engineering, 2006: Mester E, Mester AF, Mester A. The biomedical effects of laser application. Lasers Surg Med 1985;5(1): Stein A, Benayahu D, Maltz L, Oron U. Low-level laser irradiation promotes proliferation and differentiation of human osteoblasts in vitro. Photomed Laser Surg 2005;23(2): Wakabayashi H, Hamba M, Mastumoto K, Tachibana H. Effect of irradiation by semiconductor laser on responses evoked in trigeminal caudal neurons by tooth pulp stimulation. Lasers Surg Med 1993;13(6): Tunér J, Hode L. Laser therapy: Clinical practice and scientific background. Grängesberg, Sweden: Prima Books AB, 2002: Chapter 11 The mechanisms (pp ). 8. Hawkins D, Abrahamse H. Effect of multiple exposures of low-level laser therapy on the cellular responses of wounded human skin fibroblasts. Photomed Laser Surg 2006;24(6): Baxter GD. Principles and practice of laser treatment. Chapter 7 in: Baxter GD. Therapeutic lasers: Theory and practice. Edinburgh, UK: Churchhill Livingstone, 1994: Bjordal JM, Johnson MI, Iversen V, Aimbire F, Lopes-Martins RAB. Low-level laser therapy in acute pain: A systemic review of possible mechanisms of action and clinical effects in randomized placebocontrolled trials. Photomed Laser Surg 2006;24(2): Gerbi MEM, Pinheiro ALB, Marzola C, Limeira Júnior Fde A, Ramalho LMP, Ponzi EAC, Soares AO, Carvalho LCB, Lima HV, Gonçalves TO. Assessment of bone repair associated with the use of organic bovine bone and membrane irradiated at 830nm. Photomed Laser Surg 2005;23(4): Aras MH, Güngörmüş M. The effect of low-level laser therapy on trismus and facial swelling following surgical extraction of a lower third molar. Photomed Laser Surg 2009;27(1): Bjordal JM, Tuner J, Iversen VV, Frigo L, Gjerde K, Lopes-Martin RAB. A systematic review of postoperative pain relief by low level laser therapy (LLLT) after third molar extraction. In: The 1st meeting of the European Division of the World Federation for Laser Dentistry, April 26-27, 2007, Nice, Ross and Ross 123

16 CLINICAL REVIEW AND CASE REPORTS France. Lasers Med Sci 2007;22(4):303, abstract O Tunér J, Hode L. Laser therapy: Clinical practice and scientific background. Grängesberg, Sweden: Prima Books AB, 2002: Brugnera Junior A, Zanin FAA, Zanin T, Bissoli CZ, Carvalhosa AA, Castro PHS. Prevention and treatment of oral mucositis with diode laser 660 nm in patients with head and neck cancer submitted to radiotherapy and/or chemotherapy. Photomed Laser Surg 2007;25(4): , Abstract Corti L, Chiarion-Sileni V, Aversa S, Ponzoni A, D Arcais R, Pagnutti S, Fiore D, Sotti G. Treatment of chemotherapy-induced oral mucositis with light-emitting diode. Photomed Laser Surg 2006;24(2): Schindl A, Neumann R. Low-intensity laser therapy is an effective treatment for recurrent herpes simplex infection. Results from a randomized double-blind placebocontrolled study. J Invest Dermatol 1999;113(2): Marei MK, Abdel-Meguid SH, Mokhtar SA, Rizk SA. Effect of lowenergy laser application in the treatment of denture-induced mucosal lesions. J Prosthet Dent 1997;77(3): Tunér J, Hode L. Laser therapy: Clinical practice and scientific background. Grängesberg, Sweden: Prima Books AB, 2002: Tunér J, Hode L. Laser therapy: Clinical practice and scientific background. Grängesberg, Sweden: Prima Books AB, 2002: Hagiwara S, Iwasaka H, Hasegawa A, Noguchi T. Pre-irradiation of blood by gallium aluminum arsenide (830 nm) low-level laser enhances peripheral endogenous opioid analgesia in rats. Anesth Analg 2008;107(3): Wakabayashi H, Hamba M, Matsumoto K, Tachibana H. Effect of irradiation by semiconductor laser on responses evoked in trigeminal caudal neurons by tooth pulp stimulation. Lasers Surg Med 1993;13(6): Kotlow L. Lasers and pediatric dental care. Gen Dent 2008;56(7): Schlager A, Offer T, Baldissera I. Laser stimulation of acupuncture point P6 reduces postoperative vomiting in children undergoing strabismus surgery. Br J Anaesth 1998;81(4): Lopes CB, Pinheiro ALB, Sathaiah S, Da Silva NS, Salgado MAC. Infrared laser photobiomodulation (λ 830 nm) on bone tissue around dental implants: A Raman spectroscopy and scanning electronic microscopy study in rabbits. Photomed Laser Surg 2007;25(2): Pretel H, Lizarelli RFZ, Ramalho LTO. Effect of low-level laser therapy on bone repair: Histological study in rats. Lasers Surg Med 2007;39(10): Lopes CB, Pinheiro ALB, Sathaiah S, Duarte J, Martins MC. Infrared laser light reduces loading time of dental implants: A Raman spectroscopic study. Photomed Laser Surg 2005;23(1): Youssef M, Ashkar S, Hamade E, Gutknecht N, Lampert F, Mir M. The effect of low-level laser therapy during orthodontic movement: A preliminary study. Lasers Med Sci 2008;23(1): Sun X, Zhu X, Xu C, Ye N, Zhu H. [Effects of low energy laser on tooth movement and remodeling of alveolar bone in rabbits.] Hua Xi Kou Qiang Yi Xue Za Zhi [West China J Stomatol] 2001;19(5): Chinese. 30. Turhani D, Scheriau M, Kapral D, Benesch T, Jonke E, Bantleon HP. Pain relief by single low-level laser irradiation in orthodontic patients undergoing fixed appliance therapy. Am J Orthod Dentofacial Orthop 2006;130(3): Angelov N, Pesevska S, Nakova M, Gjorgoski I, Ivanovski K, Angelova D, Hoffmann O, Andreana S. Periodontal treatment with lowlevel diode laser: Clinical findings. Gen Dent 2009;57(5): Amorim JCF, de Sousa GR, de Barros Silveira L, Prates RA, Pinotti M, Ribeiro MS. Clinical study of the gingiva healing after gingivectomy and low-level laser therapy. Photomed Laser Surg 2006;24(5): Ozcelik O, Cenk Haytac M, Kunin A, Seydaoglu G. Improved wound healing by low-level laser irradiation after gingivectomy operations: A controlled pilot study. J Clin Periodontol 2008;35(3): Kert J, Rose L. Clinical laser therapy: Low level laser therapy. Reiss E, translator. Veksoe, Denmark: Scandinavian Medical Laser Technology, 1989: Kutvolgyi I. Low level laser therapy as a diagnostic tool in dentistry. Laser Ther 1998;10: Marsilio AL, Rodrigues JR, Borges AB. Effect of the clinical application of the GaAlAs laser in the treatment of dentine hypersensitivity. J Clin Laser Med Surg 2003;21(5): Pesevska S, Nakova M, Ivanovski K, Angelov N, Kesic L, Obradovic R, Mindova S, Nares S. Dentinal hypersensitivity following scaling and root planing: Comparison of low-level laser and topical fluoride treatment. Lasers Med Sci. Epub 2009 Jun 1. DOI /s Carvalho CM, de Lacerda JA, Dos Santos Neto FP, Cangussu MCT, Marques AMC, Pinheiro ALB. Wavelength effect in temporomandibular joint pain: A clinical experience. Lasers Med Sci. Epub 2009 Jun 30. DOI /s y. 39. Pinheiro ALB, Cavalcanti ET, Pinheiro TITNR, Alves MJPC, Manzi CTA. Low-level laser therapy in the management of disorders of the maxillofacial region. J Clin Laser Med Surg 1997;15(4): Tunér J, Hode L. Laser therapy: Clinical practice and scientific background. Grängesberg, Sweden: Prima Books AB, 2002: Chapter 8 Contraindications (pp ). 41. Lopes-Martins RAB, Albertini R, Lopes-Martins PSL, de Carvalho FAS, Neto HCCF, Iversen VV, Bjordal JM. Steroid receptor antagonist mifepristone inhibits the anti-inflammatory effects of photoradiation. Photomed Laser Surg 2006;24(2): Ross and Ross

17 Photobiomodulating Lasers and Children s Dental Care Lawrence Kotlow, DDS, Albany, New York J Laser Dent 2009;17(3): CLINICAL REVIEW AND CASE REPORTS INTRODUCTION Peer-reviewed, evidenced-based studies describing the benefits of using hard and soft tissue lasers are well documented in the dental literature. The use of the erbium family of lasers, 1 Nd:YAG lasers, 2 diode lasers, 3 carbon dioxide lasers, 4 and argon lasers 5 and are well understood and used around the world. Photobiomodulating (PBM) lasers are devices that produce energy levels below 0.5 Watt and are not used for invasive surgical procedures. 6-7 PBM lasers do not produce or require temperature elevation in a target tissue (i.e., photothermal effects), but rather create a photobiomodulation effect within the target tissue. The benefits and usage of these lasers are gaining acceptance within the dental community and are often identified by different names. The most common descriptions are cold lasers, healing lasers, and low-level laser therapy (LLLT). 8 The beneficial effects are described as a photobiological or photochemical effect on the target tissue Lowlevel lasers produce energy in a range of milliwatts (mw). PBM lasers produce a stimulation and/or suppression of biological processes and allow the tissue to generate an intracellular or biological response. The present body of knowledge of PBM suggests that one of the major effects is created within the cell mitochondria and results in an increase the cell s fuel for energy and repair, or adenosine 8, triphosphate (ATP). PBM lasers are often semiconductor diode lasers. The author is familiar with two general types: one, consisting of InGaAIP (Indium- Gallium-Aluminum-Phosphide) in the visible light range of 630 to 680 nm; and two, GaAlAs (Gallium- Aluminum-Arsenide) in the invisible range of 750 to 910 nm. Other wavelengths can also be used. 12 PBM lasers affect damaged cells and do not produce harmful or negative effects on healthy cells. The U.S. Food and Drug Administration (FDA) categorizes photobiomodulating lasers as posing no significant risk (NSR) and therefore these devices are considered safe. In the medical community, the FDA has given marketing clearance for such procedures as pain control and carpel tunnel syndrome treatment. At this time, all dental applications should be considered off-label usage in the United States. Essentially, this means that there is no indication for use statement in the operating manual. (For more information on regulatory approval, please refer to Sulewski JG. Clearing the FDA hurdle, from initial device application through regulatory approval to the clinical operatory: An update on dental laser marketing clearances, J Laser Dent 17(2):81-86.) In spite of the NSR designation, the author avoids using PBM lasers on patients who are pregnant or who have malignancies. There are three types of effects of photobiomodulating laser therapy: a primary local event which is simply absorption of the light directly by the cellular chromophores or cytochromes; and secondary changes induced by cells that have absorbed photons which initiate cell-specific responses such as increased cell metabolism and blood circulation. These beneficial ABSTRACT Many laser instruments are available for treating oral disease. Some treatments involve removal of hard and/or soft dental tissue. However, other beneficial therapeutic results can occur without a photothermal event, and these effects are known as photobiomodulating or low-level laser effects. They can be produced by all lasers; however, specific photobiomodulating laser instruments are available that operate at levels below 500 mw and can be used to provide a wide range of benefits. This article will describe the many uses for these devices used in the author s pediatric dental practice. effects can occur in areas of the body not being directly irradiated. 12 It should be mentioned that there is some controversy in the scientific community about PBM effects; however, more than 2500 articles have been written and accepted. The effects produced by nonsurgical lasers are not limited to low-level lasers. Hard and soft tissue lasers, which are used for surgical procedures, also are capable of producing beneficial PBM effects when used in noncontact, defocused modes. Thus at low energy output levels (less than 500 mw) they do not appear to produce heat build-up within the irradiated tissue. Examples of PBM effects that may be attributed to the nonthermal effect of hard and soft tissue lasers are treatment of postsurgical discomfort; treatment of postsurgical or acute infection, pain, and swelling due to trauma; and maintaining vitality of injured teeth. 15 Kotlow 125

18 CLINICAL REVIEW AND CASE REPORTS PBM devices may consist of a nonlaser cluster of light-emitting diodes (LEDs) of various wavelengths or may be a single wavelength laser probe emitting at 660, 808, or 830 nm. Examples of both such devices as used by the author are shown in the accompanying table. Typically the cluster type used for treatment provides between 4 to 12 Joules (J) per minute externally, and intraoral probes provide between 2 to 8 J per minute. PBM USES IN TREAT- MENT OF PEDIATRIC PATIENTS 1. Reduction of pain and creation of an analgesic effect during restorative dental procedures The capability to produce an analgesic effect allows PBM devices to reduce and often eliminate the need for a local anesthetic during restorative dental procedures. A tooth being treated is not numb, however the ability of the body to recognize or feel pain appears to be significantly reduced. 16 Teeth exposed to laser therapy have lower levels of pain as compared to those with the placebo treatment. A photobiomodulating effect can be accomplished by using PBM lasers that are limited to low-level energy (a 660-nm probe on either the Q1000 or the AcuLASER in a AcuLASER Q1000 contact mode) or by using an erbium family laser (2940-nm Er:YAG or 2780-nm Er,Cr:YSGG) in a defocused mode. 17 To achieve an analgesic effect, the author places the tip of the laser in a defocused mode (noncontact, 1 to 3 mm from the tooth surface) when using a 660-nm probe over the crown of the tooth for 1 to 2 minutes, as shown in Figure 1. When an erbium family laser is used, as depicted in Figure 2, the laser s tip is maintained in a defocused mode in continuous motion. This will prevent production of thermal effects within the tooth. Using this technique, the author has found that it is often possible to complete a cavity preparation with the erbium laser without a need for anesthesia. In most instances, while preparing primary teeth and many permanent teeth, it is possible to also use a high-speed dental handpiece to complete the cavity preparation without causing the patient discomfort. (If the patient has not previously experienced the vibrations of the high-speed or low-speed handpiece, there is no preconceived fear factor.) Regardless of the final restoration, the patient is able to leave the dental office without a numb lip, tongue, or cheek. This is especially important in young children, where the potential for developing a lip or tongue injury due to the child s biting is often a concern. P HOTOBIOMODULATING DEVICES Model Manufacturer Type Wavelength(s) MedX Home Unit DioBeam 830 Laserex Technologies, Unley, Australia 2035, Inc., Rapid City, S.D., USA MedX Health Corp., Mississauga, Ontario, Canada Laser Light Canada, Tottenham, Ontario, Canada LED Cluster LED Cluster: 8 LEDs/12 diodes Diode cluster: 9 red diodes and 40 infrared diodes Single Probe 660 nm nm 660-nm probe 808-nm probe 633 and 880 nm 830 nm Figure 1: View depicting placement of a PBM laser for tooth analgesia Figure 2: View depicting placement of an Er:YAG laser for tooth analgesia 2. Treatment of injured anterior primary teeth Accidental injuries to maxillary or mandibular anterior primary teeth are quite common in young children. The result of trauma may often result in pulpal death, tooth discoloration, and possibly future infection and damage to developing permanent teeth In untreated teeth, such changes will often occur within 2 to 6 weeks after a child has sustained an injury to the upper incisors. PBM has been shown to be beneficial, 15 and the author has treated infants and toddlers, ranging from 7 months to 5 years of age, with a 660-nm laser probe. After receiving injuries to this area, those patients have had the involved tooth or teeth remain vital. In instances where these teeth were slightly mobile, partially avulsed, or displaced and were treated within 24 to 48 hours after an injury, the teeth demonstrated both clinically and radiographically the ability to remain normal in color, maintain vitality, and remain asymptomatic over three or four years. Successful treatment consists of 126 Kotlow

19 CLINICAL REVIEW AND CASE REPORTS placing a PBM laser probe on the facial and palatal area of the traumatized tooth for 1 minute. It may be advantageous, in some instances, to re-treat the affected tooth or teeth similarly at 3- and 5- day intervals after the accident. Case 1: A child presented who had fallen and partially extruded the maxillary central incisors. The initial radiograph in Figure 3 shows the initial injury. Treatment consisted of repositioning the teeth with manual pressure and then placing the 660-nm laser probe over the labial surface of the crowns and roots for 1 minute each on the facial and lingual aspects for a dosage of approximately 4 J/min. Figure 4 depicts the successful maintenance of the teeth 1 year later. 3. Treatment of permanent tooth trauma Case 2: A 10-year-old female child was seen due to tooth #9 being partially avulsed. A clinical and radiographic examination revealed the tooth was extruded from the tooth socket approximately 5 mm (Figure 5). The tooth was gently repositioned into the Figure 3: Radiograph of initial injury, with a partial avulsion of the two central incisors Figure 4: One-year post-treatment view of anterior teeth showing stable dentition and periodontal health correct position by having the patient slowly bite on a crown seater. Once the tooth appeared to be in correct alignment, it was splinted into place with a band of composite (Figure 6). The tooth was then exposed to the 660-nm probe for 1 minute facially and 1 minute palatally. This procedure was repeated in three days and again at 7 days post-trauma. At the end of 23 months (Figure 7) the tooth remained vital and asymptomatic, both clinically and radiographically. 4. Treatment of inability to open the oral cavity due to cellulitis and muscle trismus Patients seen for emergency visits due to oral infections may have difficulty opening their mouth adequately to allow an accurate examination of the oral cavity, as shown in Figure 8. PBM therapy could provide some relief. 20 This condition may be due to trauma or infection of an abscessed tooth. This lack of access may prevent drainage and relief of pain of an infected tooth. Placing the Q1000 instrument over the affected area in a contact position for three minutes gave the patient enough relief to Figure 5: Radiograph of partially avulsed left central incisor Figure 6: View of composite splint in place allow for adequate opening and drainage of the infected tooth area. 5. Treatment of temporomandibular joint (TMJ) and postorthodontic adjustment discomfort PBM therapy has been shown to be effective in treatment of TMJ pain 21 as well as for alleviation of discomfort during orthodontic procedures. 22 Case 3: A 13-year-old female patient presented with a history of morning pain in the areas of both left and right ears. An oral examination revealed many TMJ discomfort signs: ringing in the ears, jaw pain upon chewing and opening her mouth fully. The patient was treated for three visits (using the Q1000 for a 3-minute cycle on the left side and the MedX cluster on the right side), externally over the TMJ areas on alternate days (Figure 9). In addition, the 660-nm laser (2.2 Joules) Figure 7: Twenty-three months post-treatment, showing normal tooth alignment and healthy tissue Figure 8: Extraoral view of a typical patient who presents with a severe infection due to pulpitis Kotlow 127

20 CLINICAL REVIEW AND CASE REPORTS was applied intraorally for 1 minute on each trigger point (Figure 10). The patient indicated she felt relief immediately and after 3 days was essentially pain-free. Figure 11 shows the Q1000 device being used for treatment of postorthodontic adjustment discomfort. 6. Elimination the gag reflex A simple solution for many gaggers is to place a small dab of salt on the tip of the tongue. Unfortunately, this method does not work on all patients. Stimulation of the acupuncture point on the inside area of the wrists, known as the P6 meridian, can reduce the nausea and gagging sensations The P6 point is positioned on the undersurface of the wrist approximately 1 inch from the wrist crease; this is approximately the width of the distal thumb phalanx. Applying laser energy using 4 Joules of the MedX (either the 633- or 880-nm wavelengths) held in contact, perpendicular to the tissue on the P6 point can often provide sufficient relief to eliminate a gag reflex. Strong gag reflexes prevent the taking of intraoral radiographs, placement of rubber dam, or visualization and treatment of dental caries, especially in the most distal point of upper molars. Such areas may be successfully treated when the PBM laser is placed on the P6 acupuncture point for 1 minute, as shown in Figure Treatment of soft tissue injuries Benefits of pretreatment of surgical sites or post-traumatic soft tissue injuries with the PBM laser include reducing postsurgical pain and allowing the inflammatory response to start earlier These effects are thought to be the result of laser light affecting both the cell membrane and components within the nucleus of the cell. This results in stimulating and accelerating the rate of healing; reducing and resolving tissue inflammation; providing significant pain relief; Figure 9: Extraoral treatment of of TMJ condition Figure 10: Intraoral treatment of trigger points improving tensile strength of the wound; and stimulating the immune system to resolve infection. The tertiary effect of irradiating one area of the body and having similar effects manifest elsewhere on other wounds of the body suggests a systemic effect of PBM laser energy. 12 This appears to be a significant reason why it is difficult to create a study using the left and right side of the same patient. The systemic effects prevent the examiner from determining whether there is a difference between a placebo effect and the laser s effect. Case 4: A 4-year-old boy received an injury to his upper teeth and soft tissue when playing roller coaster at home on furniture. The anterior teeth were treated with the DioBeam 830 intraorally at 4 J/min and the MedX cluster laser extraorally at a setting of 3 J/min. This treatment was performed on the initial appointment and again on the following day (Figures 13-16). The patient has been seen for two years following the incident, and the teeth have remained stable without infection. 8. Treatment of intraoral lesions Children presenting with viral stomatitis or herpetic-like lesions Figure 11: Extraoral treatment of a patient having discomfort with orthodontic treatment. The device is positioned directly over the affected area Figure 12: Placement of the laser on the P6 acupuncture point can benefit from PBM treatment using a variety of devices, especially if the treatment can begin near the first appearance of the problem Case 5: A 10-year-old patient presented with multiple lesions intraorally and significant discomfort. The Q1000 was placed extraorally for 3 minutes (Figure 17). The patient returned 4 days later with reports of no discomfort and with most of the lesions healed. In the author s experience, since the laser energy scatters through the tissue, some areas may absorb different amounts of that energy and not fully resolve. Those lesions would require additional treatment on a subsequent appointment. Case 6: As a final example, a surgical laser (DioDent Micro 980, HOYA ConBio, Fremont, Calif.) was used to treat a child who presented with herpes labialis. For further information, see Kotlow L. Treatment of aphthous ulcers and herpes labialis. J Laser Dent 128 Kotlow

21 CLINICAL REVIEW AND CASE REPORTS Figure 15: One month post-trauma Figure 13: Examination of initial trauma Figure 17: Extraoral laser application Figure 14: Two days post-treatment 2008;16(Spec. Issue): Treatment consisted of lasing the entire upper left quadrant for 2 minutes using a defocused tip according to the manufacturer s instruction for this indication for use. The power density is within the parameters of PBM. Figures show the perioperative and two-day postoperative views. CONCLUSION Photobiomodulating lasers provide pediatric dental patients many benefits including reducing the discomfort and pain from surgical sites and injuries; reducing the duration of healing from trauma and soft tissue surgery traumatic injuries; eliminating or reducing the gag reflex and nausea; and relieving muscle discomfort from postorthodontic adjustments. The mechanisms of these benefits are still undergoing investigation and need more scientific studies to allow for proper understanding. AUTHOR BIOGRAPHY Dr. Lawrence Kotlow has had a private dental practice located in Albany, New York since 1974, Figure 16: Radiograph one month posttrauma specializing in Pediatric Dentistry. He is a graduate of the University at Buffalo The State University of New York (SUNY), New York University College School of Dentistry, and the Cincinnati Children s Hospital pediatric dental postgraduate program. He is Board-certified in Pediatric Dentistry. Dr. Kotlow has Advanced Proficiency certification from the Academy of Laser Dentistry in the erbium laser and has Standard Proficiency in the Nd:YAG and diode lasers. He is a Recognized Course Provider for the Academy of Laser Dentistry and has achieved Mastership in the Academy of Laser Dentistry. Dr. Kotlow has published many articles on using the erbium laser in pediatric dentistry and contributed a chapter to the October 2004 edition of Dental Clinics of North America: Lasers in Clinical Dentistry entitled Lasers in Pediatric Dentistry. He has lectured throughout the United States, Canada, Australia, and Taiwan about pediatric dentistry and lasers. Dr. Kotlow may be contacted by at lkotlow@aol.com. Figure 18: Treatment of herpes labialis with 980-nm surgical diode laser used out of contact. The white tip of an evacuation system is shown in the lower portion of the photograph Figure 19: Forty-eight hours post-treatment showing good healing Disclosure: Dr. Kotlow has evaluated and beta-tested new equipment for various dental and laser companies such as Lares, Schick, HOYA ConBio, and Innovative Optics. REFERENCES 1. Kotlow L. The use of the erbium hard & soft tissue laser in the pediatric dental practice. J Southeast Soc Pediatr Dent 2001;17: White JM, Goodis HE, Rose CL. Use of the pulsed Nd:YAG laser for intraoral soft tissue surgery. Lasers Surg Med 1991;11(5): Magid KS, Strauss RA. Laser use for esthetic soft tissue modification. Dent Clin North Am 2007;51(2): Kotlow 129

22 CLINICAL REVIEW AND CASE REPORTS 4. Wilder-Smith P, Arrastia A-MA, Liaw L-H, Berns M. Incision properties and thermal effects of three CO 2 lasers in soft tissue. Oral Surg Med Oral Pathol Oral Radiol Endod 1995;79(6): Powell GL, Ellis R, Blankenau RJ, Schouten JR. Evaluation of argon laser and conventional light-cured composites. J Clin Laser Med Surg 1995;13(5): Walsh LJ. The current status of low level laser therapy in dentistry. Part 1. Soft tissue applications. Aust Dent J 1997;42(4): Walsh LJ. The current status of low level laser therapy in dentistry. Part 2. Hard tissue applications. Aust Dent J 1997;42(5): Ross G, Ross A. Low level lasers in dentistry. Gen Dent 2008;56(7): Kotlow L. Lasers and pediatric dental care. Gen Dent 2008;56(7): Sun G, Tunér J. Low-level laser therapy in dentistry. Dent Clin North Am 2004;48(4): Corazza AV, Jorge J, Kurachi C, Bagnato VS. Photobiomodulation on the angiogenesis of skin wounds in rats using different light sources. Photomed Laser Surg 2007;25(2): Tunér J, Hode L. Laser therapy: Clinical practice and scientific background. Grängesberg, Sweden: Prima Books AB, 2002: Chapter 3 Biostimulation (pp ) and Chapter 11 The mechanisms (pp ). 13. Tunér J, Hode L. It s all in the parameters: A critical analysis of some well-known negative studies on low-level laser therapy. J Clin Laser Med Surg 1998;16(5): Tunér J, Hode L. 100 positive double blind studies Enough or too little? In: Longo L, Hofstetter AG, Pascu M-L, Waidelich WRA, editors. Laser Florence 99 A window on the laser medicine world, October 28-31, 1999, Florence, Italy. Proc. SPIE Bellingham, Wash.: SPIE The International Society for Optical Engineering, 1999: Tunér J, Hode L. Laser therapy: Clinical practice and scientific background. Grängesberg, Sweden: Prima Books AB, 2002: Chapter 5 Dental laser therapy (pp ). 16. Whitters CJ, Hall A, Creanor SL, Moseley H, Gilmour WH, Strang R, Saunders WP, Orchardson R. A clinical study of pulsed Nd:YAG laser-induced pulpal analgesia. J Dent 1995;23(3): Erratum in: J Dent 1996;24(1-2): Genovese MD, Olivi G. Laser in paediatric dentistry: Patient acceptance of hard and soft tissue therapy. Eur J Paediatr Dent 2008;9(1): Fried I, Erickson P. Anterior tooth trauma in the primary dentition: Incidence, classification, treatment methods, and sequelae: A review of the literature. ASCD J Dent Child 1995;62(4): Borum MK, Andreasen JO. Sequelae of trauma to primary maxillary incisors. I. Complications in the primary dentition. Endod Dent Traumatol 1998;14(1) Tunér J, Hode L. Laser therapy: Clinical practice and scientific background. Grängesberg, Sweden: Prima Books AB, 2002: Chapter 4 Medical indications (pp ). 21. Carvalho CM, de Lacerda JA, dos Santos Neto FP, Cangussu MCT, Marques AMC, Pinheiro ALB. Wavelength effect in temporomandibular joint pain: A clinical experience. Lasers Med Sci. Epub 2009 Jun 30. DOI 1007/s y. 22. Turhani D, Scheriau M, Kapral D, Benesch T, Jonke E, Bantleon HP. Pain relief by single low-level irradiation in orthodontic patients undergoing fixed appliance therapy. Am J Orthod Dentofacial Orthop 2006 Sep;130(3): Schlager A, Offer T, Baldissera I. Laser stimulation of acupuncture point P6 reduces postoperative vomiting in children undergoing strabismus surgery. Br J Anaesth 1998;81(4): Agarwal A, Bose N, Gaur A, Singh U, Gupta MK, Singh D. Acupressure and ondansetron for postoperative nausea and vomiting after laparoscopic cholecystectomy. Can J Anesth 2002;49(6): Dundee JW, Yang J. Prolongation of the antiemetic action of P6 acupuncture by acupressure in patients having cancer chemotherapy. J R Soc Med 1990;83(6): Mendez TMTV, Pinheiro ALB, Pacheco MTT, Ramalho LMP, Nascimento PM. Assessment of the influence of the dose and wavelength of LLLT on the repair of cutaneous wounds. In: Rechmann P, Fried D, Hennig T, editors. Lasers in dentistry IX, January 26-27, 2003, San Jose, Calif. Proc. SPIE Bellingham, Wash.: SPIE The International Society for Optical Engineering, 2003: Simon A. Low level laser therapy for wound healing: An update. IP22 information paper [Internet]. Edmonton, Alberta, Canada: Alberta Heritage Foundation for Medical Research, [Cited 2010 Jan 2.] 36 p. Available from: Woodruff LD, Bounkeo JM, Brannon WM, Dawes KS Jr, Barham CD, Waddell DL, Enwemeka CS. The efficacy of laser therapy in wound repair: A meta-analysis of the literature. Photomed Laser Surg 2004;22(3): Toida M, Watanabe F, Goto K, Shibata T. Usefulness of low-level laser for control of painful stomatitis in patients with hand-foot-and-mouth disease. J Clin Laser Med Surg 2003;21(6): Parkins F, O Toole T, Yancy J. Nd:YAG laser treatment of aphthous and herpetic lesions. J Dent Res 1994;73(Spec Issue):190, abstract Colvard M, Kuo P. Managing aphthous ulcers: Laser treatment applied. J Am Dent Assoc 1991;122(6): Convissar RA. Aphthous ulcers and lasers. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996;82(2): Kotlow LA. Pediatric dentistry begins at birth: Lasers and pediatric dental care in treating soft tissue lesions in the dental office. J Pediatr Dent Care 2007;13(1): Kotlow

23 CLINICAL REVIEW AND CASE REPORTS Photodynamic Antimicrobial Chemotherapy in the General Dental Practice Steven Parker, BDS, LDS RCS, MFGDP, MALD, Harrogate, United Kingdom J Laser Dent 2009;17(3): INTRODUCTION Laser photonic energy can be absorbed by target tissue and molecular elements. In the surgical excision of tissue, such energy is rapidly converted into thermal energy that causes physical disruption and possible vaporization. Relative to each target tissue and corresponding incident laser wavelength exists a thermal threshold, below which the incident photonic energy values are insufficient to initiate disruption, resulting in reversible warming. 1 At much lower incident energy levels, intracellular structures such as cell mitochondria can absorb incident photonic energy, resulting in stimulation of adenosine triphosphate and ultimately in an increase in cell respiration. 2 Such low-level laser action has been well documented, 3 reflecting a general process of energy transfer within such structures. A procedure used in cancer treatment called photodynamic therapy (PDT) utilizes this energy transfer. 4 Allied to investigations into lowlevel laser effects, it has been shown that certain chemotherapeutic agents possess similar capacity for electron transfer in the presence of photonic energy. 5 Where this occurs in close proximity to host tissue and in particular tissue oxygen, reactive oxygen species can be formed simultaneously with singlet oxygen. Ultimately, these reactions will kill cells through 4, 6-7 apoptosis or necrosis. The major outcome of such knowledge has been seen in the general principles of photodynamic therapy in the treatment of neoplastic tumors. 8-9 However, similar effects have been demonstrated in vitro, using low-level photonic energy on selected bacterial species with some success. This has led to the emergence of photodynamic antimicrobial chemotherapy (PACT) in treating a broad range of bacterial infections in the mouth. This paper reviews the process of energy transfer in PACT, the development of clinical protocols, and the applications of PACT in clinical dentistry. COMPONENTS AND MECHANISMS Light has been used for therapeutic purposes for several centuries. Initially, ultraviolet radiation was applied in the treatment of acne vulgaris, skin tuberculosis, and rickets With the development of light-absorbing properties and fluorescence of various dyes, it was realized that these chemicals, when photoexcited, were capable of exerting destructive effects on target cells. This process was termed photodynamic action and further research into the mechanisms involved gave rise to an understanding of dye-sensitized photo-oxidation of molecular oxygen. A photosensitizer is a chemical compound that readily undergoes photoexcitation and then transfers its energy to other molecules. 5 Usually the photosensitizer is excited from a ground singlet state (quantum state with zero spin angular momentum) to an excited singlet state. It then undergoes intersystem crossing to a longer-lived excited triplet state. In this state, two reactions are possible as mentioned above. 4 When the photosensitizer and an oxygen molecule are in proximity, an energy transfer can take place that allows the photosensitizer to relax to its ground singlet state and create an excited singlet-state oxygen molecule. Singlet oxygen is a very aggressive chemical species and will very rapidly react with any nearby biomolecules. 7 GLOSSARY Various acronyms have been used to describe the processes whereby incident low-level laser radiation might provide energy to aid diagnosis and therapy. PDT: Photodynamic therapy. The use of subablative incident laser radiation to activate a chosen photosensitizer and effect a predetermined photochemical change in surrounding host tissue. PAD: Photo-activated disinfection. A descriptive term adopted by certain manufacturers to suggest the elimination of target bacteria, using a suitable photosensitizer, such as tolonium chloride or methylene blue. PACT: Photodynamic antimicrobial chemotherapy. A more precise descriptive term that reflects the use of photonic energy to drive a chemotherapeutic action resulting in antimicrobial action. There are more than 400 compounds that have been shown to exhibit photosensitizing properties, either in vitro or in vivo. 14 Some of the more significant may be summarized as follows: phenothiazine dyes e.g., methylene blue (MB) and toluidine blue O (TBO; tolonium chloride) phthalocyanines chlorines 19 porphyrins e.g., hematoporphyrin HCl, Photofrin, 5-ALA (aminolevulinic acid) xanthenes e.g., erythrosine. 22 The basic principle of PACT is to utilize a photosensitizer in combination with a light source to activate it. 23 Wilson and Pratten reported that neither the light source alone in the absence of the photosensitizer nor the photosensitizer alone in the absence of the light source had any significant effect on the simulated Parker 131

24 CLINICAL REVIEW AND CASE REPORTS antibacterial therapy. 18 In contrast, Dörtbudak et al. demonstrated that application of toluidine blue O alone resulted in significant reduction of some, but not all, bacterial species tested. 24 In the above studies, all of the compounds except erythrosine were activated by visible red light in the wavelength range of 630 to 662 nm produced by a laser; an ordinary tungsten lamp was used in a study of erythrosine s effectiveness, 22 but that compound has a maximum absorption in the 500 to 550-nm range, which is blue and green light. Wilson and Patterson have suggested a 700 to 850-nm range of energy for an ideal photosensitizer. Nonetheless, a diode laser is usually used for photodynamic procedures. 23 As outlined above, the photosensitizer compound in its ground state is activated by light and transformed into a high energized triplet state. Two mechanisms of action explain the effectiveness of PACT: 25 The triplet compound interacts with the cell s organic substrate molecule, producing free radicals and radical ions. These in turn react with endogenous oxygen and reactive oxygen species (ROS) such as hydrogen peroxide and hydroxyl radicals which irreversibly damage the cell s membrane. ROS compounds can also damage subcellular organelles and enzymes as well as DNA. 26 The triplet compound interacts directly with the molecular oxygen to produce a singlet oxygen, which is highly reactive. It also causes irreparable cellular damage, including the cell wall. Although both mechanisms exist in relation to each other, singlet oxygen generally produces the lethal bacterial effects of PACT. The interaction is extremely rapid, since the radius of action of singlet oxygen is estimated to be on the order of 0.01 to 0.02 µm, corresponding to a lifetime of 0.01 to 0.04 µs in cells. 27 There is limited migration of the molecule from its formative site, thus its effect is very localized. The advantage is that surrounding structures can be preserved; 25 however, the placement of the photosensitizer should be as close to the infection as possible. CLINICAL APPLICATIONS The majority of the common disorders within the oral cavity are due either to bacterial causes or are exacerbated by secondary bacterial contamination. Notwithstanding the need for the clinician to correctly diagnose the condition and address all local and systemic contributory factors, the elimination of pathogenic bacteria has represented a core objective. In addition to the presence of bacterial colonies, the existence of a biofilm can constitute a formidable barrier to many local applied therapies and systemic antibiotic use has led to inconsistent results. Of significance to the latter, antibiotic resistance and systemic side effects may present a challenge and deter the casual use of such therapies The consequence of risk associated with concomitant bacteremia during periodontal and restorative treatment has been the subject of a recent review. 34 Over more than 40 years, prophylactic administration of systemic antibiotics has been considered best practice in those patients at risk of bacterial endocarditis and, despite recommendations to the contrary, the controversy remains. 35 Mechanical instrumentation, including scaling and root planing and the use of ultrasonics, has been advocated to provide adjunctive debridement in periodontal and periimplantitis treatment. The efficacy of such treatment may be compromised by lack of direct access to the treatment site and the possible risk to underlying healthy tissue. The photothermal interaction of lasers, using supra-ablation threshold values, can produce tissue temperatures to aid in bacterial reduction. 36 With regard to the sole use of ablative laser energy in bactericidal effects, the following phenomena may be considered as limiting factors: Primary bactericidal action linked to absorption characteristics Primary interaction coaxial with laser beam Risk of collateral damage associated with nontarget absorption and thermal rise Other difficulties access, limitations of delivery tip design, etc. Conversely, the use of a nonablation, low-level laser wavelengths to initiate photodynamic antimicrobial chemotherapy in a suitably administered photosensitizer may be seen to have the following advantages over conventional laser use: Nonsurgical (subablative) photonic energy values employed Primary (indirect) interaction through chemical mediator (photosensitizer) Little risk of collateral damage within confined target sites. Methylene blue as a photosensitizer should be used with caution and in dilute doses, to avoid possible toxicity 37 The use of noncollimated light through a diffuser tip can overcome limited access and be further compensated by scatter through the body of the liquid sensitizer. Local infections such as those that occur within the oral cavity may be potential targets for antibacterial photodynamic therapy, in addition to other mechanical debridement techniques. The supra- and subgingival plaque biofilm on tooth surfaces is often easily accessible for flushing with the dye and activation with the low-level laser light. During the last decade, an increasing number of studies have been published that describe the effect on periodontal pathogenic bacteria by photodynamic methods. These investigations have underlined the introduction of PACT into the practice of periodontology Other investigations have shown the use of PACT in the treatment of a number of pathogenic bacterial and fungal infections, summarized as follows: Tooth surface disinfection prior to dental treatment Parker

25 CLINICAL REVIEW AND CASE REPORTS Figure 1: Periowave, a low-level laser device, capable of use with a photosensitizer Disinfection of infected root canals 44 Periodontology Peri-implantitis 47 Antifungal 48 Antiviral. 49 Current developments in commercial low-level laser emission have given rise to several devices which emit light in the visible red region of the electromagnetic spectrum. One such instrument (PAD Plus, Denfotex Light Systems Ltd., Inverkeithing, Fife, UK) uses tolonium chloride solution as the supplied photosensitizer and is designed primarily for antibacterial action within the tooth (cavity preparation and endodontics). Another device (Periowave, Ondine Biopharma Corp., Vancouver, British Columbia, Canada, shown in Figure 1) supplies a methylene blue solution for use in periodontology, paraimplantology, and oral mucosal infection sites. The author s experience has been with the latter instrument. Figure 2 shows the device s fiber-optic delivery system, and Figure 3 shows the laser activated with emission through the diffuser tip. Use of PACT is seen as adjunctive to the reduction of bacterial pathogens and is part of the overall treatment necessary to address causative factors and repair, remodel, or restore the tissue site as required. Safety regulations must be applied as per National statutes and guidance and the Class III classification of the laser defines the use of wavelength-specific protective Figure 2: A fiber delivery system is connected to a disposable, single-use, plastic diffuser, which allows even distribution of light within the target area Figure 3: Diffuser tip with emitted laser radiation. This allows an even distribution of photonic energy thru 360 eyewear for patient and operator. The photosensitizer solution is supplied in single-use disposable vials, onto which a blunt, side-release cannula is fitted; the cannula is applied to the tissue site and a small amount of photosensitizer expelled. The laser unit is configured by the manufacturer to deliver a fixed cycle of continuous-wave light emission, enabled through a foot switch, with the following power parameters: 220 mw / 60 seconds / 13 joules. The nature of the diffuser delivery tip helps ensure that laser photonic energy is applied evenly throughout a volumetric zone of photosensitizer and is considered effective within a 1 to 2-mm distance from the diffuser tip. Therefore, in the periodontal pocket disinfection of a single root tooth site, the tip is applied at four sites (mesial, distal, facial, palatal), with additional application at bifurcation sites for molar teeth; each site is exposed to the fixed cycle of light emission. CLINICAL CASES The following clinical cases present examples of PACT. Figures 4 to 7 show adjunctive treatment of a periodontal pocket during the placement of a new crown. Figures 8 to 11 also present the use of PACT for adjunctive treatment of periodontitis. Figures 12 to 16 illustrate a case of peri-implantitis adjunctively treated with PACT. Figures 17 to 20 portray treatment of candidal cheilitis of the lip using methylene blue photosensitizer. Figures 21 to 23 depict a similar candidiasis-type lesion on the palate, treated with PACT. Figures 24 to 31 show the adjunctive use of PACT during osseous surgery as part of the treatment to resolve periodontal breakdown associated with failed fixed bridgework. Figure 4: Upper left bicuspid requiring replacement porcelain-fused-to-metal (PFM) crown. Associated gingival hyperplasia and inflammation are visible in preoperative left image. Right image shows the application of methylene blue solution, prior to exposure to laser energy Figure 5: Periodontal sulcus being exposed to laser photonic energy Parker 133

26 CLINICAL REVIEW AND CASE REPORTS Figure 6: Single-use photosensitizer syringe, blunt needle cannula, and diffuser tip Figure 10: Immediate postoperative view Figure 14: Treatment site immediately prior to application of the photosensitizer Figure 7: Completed new PFM crown with healthy tissue (right) at three weeks post-treatment Figure 11: One-month postoperative view. Clinical appearance shows lack of inflammation and bleeding Figure 15: Photosensitizer exposed to laser photonic energy, delivered through diffuser tip. After PACT is completed, guided bone regeneration (GBR) is employed in the defect Figure 8: Preoperative probing demonstrating presence of periodontal disease Figure 9: After methylene blue solution had been applied to post-scaling treatment sites, the pockets are exposed to laser photonic energy Figure 12: Probing of a diseased area of peri-implantitis. PACT will be used adjunctively with an open flap procedure that will also employ an Er:YAG laser for debridement Figure 13: Debridement of implant fixtures using an Er:YAG laser Figure 16: Postoperative clinical appearance at three months Figure 17: Close-up view of a persistent candidal cheilitis lesion of the lower lip 134 Parker

27 CLINICAL REVIEW AND CASE REPORTS Figure 18: Application of methylene blue solution to the lesion Figure 22: Application of laser photonic light diffuser tip Figure 25: Pretreatment radiograph showing bone loss Figure 19: Exposure of treatment site to activated diffuser tip. The tip is placed alongside the lesion to allow intimate exposure Figure 23: Follow-up view at two weeks post-treatment, showing appearance of resolution of inflammatory changes in epithelium Figure 26: The bridge has been removed and the periodontal defect is debrided using a surgical Er:YAG laser application Figure 20: Healing of lesion at two weeks, showing appearance of resolution of the fungal infection Figure 21: Pretreatment view of candidal denture stomatitis, showing characteristic epithelial hyperplasia and inflammation Figure 24: View of probing of the periodontal defect, which is an infrabony defect associated with teeth #11 and 12 (upper left canine, first premolar). Tooth #11 is a distal abutment for a failing fixed bridge and the defect is considered secondary to an open tooth contact. PACT will be used adjunctively to an open flap procedure, in which an Er:YAG laser will also be employed Figure 27: Additional use of an Er:YAG laser allows selective removal of subgingival calculus from root surfaces Parker 135

28 CLINICAL REVIEW AND CASE REPORTS Figure 28: Infrabony pocket debridement and calculus removal is followed immediately by PACT, using methylene blue solution and laser diffuser tip Figure 30: Healing at three months, at the time of final bridge fabrication photosensitization procedures will mitigate this concern. 25 Photosensitizers can compromise patient esthetics by producing temporary pigmentation of the periodontal tissues. Excess dye should be removed with water spray. 25 The use of photosensitizers in a paste base rather than liquid may facilitate removal through irrigation with a saline solution. 50 Should higher-powered diode lasers be used to irradiate the photosensitizer, extended duration of exposure at the same spot should be avoided to prevent thermal accumulation or injury to deeper tissues, such as bone or dental pulp. 25 Figure 29: Use of a guided bone regeneration technique, employing hydroxyapatite matrix and membrane to augment bone defect ADVANTA GES AND ADVISORIES In the author s clinical experience, the benefits to be derived from the adjunctive use of PACT in providing treatment of conditions of a bacterial origin may be summarized as follows: Straightforward clinical technique Nonsurgical protocol required for application of photosensitizer Topical / systemic antibiotics not required Useful as an adjunct to restorative / endodontic / surgery site pathogen reduction PACT can disrupt plaque biofilm, thus making it an adjunctive for use with ultrasonics, surfactant Figure 31: Radiograph at three months showing early bone in-fill Facilitates access into deep / limited-access sites (furcations, invaginations) Reduced need for surgery / direct flap approach. Patient comfort enhanced Reduced risk of bacteremia. Useful in patients with at-risk medical history Useful in treatment of mucosal pathologies candida, herpes, cheilitis GBR success enhanced following PACT. Potential drawbacks to PACT include: Possible impairment of benign oral flora which may lead to an overgrowth of a single resistant species. Staining the target selectively is seen as a way to help avoid this unwanted, potentially phototoxic reaction. 38 Photosentizers can adhere strongly to the soft tissue of the periodontal pocket and may affect periodontal attachment during wound healing. Routine removal of the dye solution after C ONCLUSION The majority of pathologies treated in everyday general dental practice can be considered to be primary bacterial infections or are complicated by secondary bacterial contamination. Many techniques have been advocated to address the need for elimination of bacterial pathogens as part of treatment and one of the claimed advantages of surgical laser use is a bacterial reduction of target sites in both hard and soft tissue management. However, the limitations of the coaxial emission of the laser beam and difficulty in accessing all sites may compromise the desired outcome. The use of laser photonic energy to activate an intermediate chemical and achieve bacterial destruction through secondary effect has been shown to offer advantages over surgical laser use. This paper has presented the underlying principles of PACT action and considered some of the areas of clinical treatment where PACT has been shown to be of benefit. Potential drawbacks are described, along with suggested measures to mitigate concerns. Differing regulatory policies have restricted a more widespread uptake of this treatment modality 136 Parker

29 CLINICAL REVIEW AND CASE REPORTS in dental practice. However, the general principles and instrumentation of photodynamic therapy in general medicine have been longaccepted globally and it is hoped that the opportunity to integrate PACT into general dental practice will allow this modality to gain in popularity. AUTHOR BIOGRAPHY Dr. Steven Parker is in private practice in Harrogate, United Kingdom, and a visiting professor in laser dentistry at the University of Genoa, Italy. He has been active in the use and teaching of laser applications in dentistry since 1990 and has lectured extensively on all aspects of laser use. He is a past president of the Academy of Laser Dentistry and currently is chair of the Academy s Education Committee. Dr. Parker may be contacted by at thewholetooth@ easynet.co.uk. Disclosure: Dr. Parker has no commercial affiliations or conflicts of interest. antibiotic resistant microorganisms: Antimicrobial photodynamic treatment. Mini Rev Med Chem 2009; 9(8): Spikes JD. Photodynamic reactions in photomedicine. Chapter 5 in: Regan JD, Parrish JA, editors. The science of photomedicine. New York: Plenum Press, 1982: Wilson BC, Patterson MS. The physics, biophysics and technology of photodynamic therapy. Phys Med Biol 2008;53(9):R61-R Nyst HJ, Tan IB, Stewart FA, Balm AJM. Is photodynamic therapy a good alternative to surgery and radiotherapy in the treatment of head and neck cancer? Photodiagnosis Photodyn Ther 2009;6(1): Hopper C. Photodynamic therapy: A clinical reality in the treatment of cancer. Lancet Oncol 2000;1(4): Scott BO. Clinical uses of ultraviolet radiation. Chapter 7 in: Stillwell GK, editor. Therapeutic electricity and ultraviolet radiation, 3rd ed. Baltimore: Williams & Wilkins, 1983: Cunliffe WJ. Diseases of the skin. Acne vulgaris. Br Med J 1973;4(5893): Qin Y, Luan X, Bi L, He G, Bai X, Zhou C, Zhang Z. Toluidine bluemediated photoinactivation of periodontal pathogens from supragingival plaques. Lasers Med Sci 2008;23(1): Wilson M, Burns T, Pratten J. Killing of Streptococcus sanguis in biofilms using a light-activated antimicrobial agent. J Antimicrob Chemother 1996;37(2): Wilson M, Pratten J. Lethal photosensitisation of Staphylococcus aureus in vitro: Effect of growth phase, serum, and pre-irradiation time. Lasers Surg Med 1995;16(3): Soukos NS, Mulholland SE, Socransky SS, Doukas AG. Photodestruction of human dental plaque bacteria: Enhancement of the photodynamic effect by photomechanical waves in an oral biofilm model. Lasers Surg Med 2003;33(3): Yu C-H, Lin H-P, Chen H-M, Yang H, Wang Y-P, Chiang C-P. Comparison of clinical outcomes of oral erythroleukoplakia treated with photodynamic therapy using either light-emitting diode or laser light. Lasers Surg Med 2009;41(9): REFERENCES 1. Parrish JA, Deutsch TF. Laser photomedicine. IEEE J Quantum Electron 1984;QE-20(12): Hamblin MR, Demidove TN. Mechanisms of low level light therapy. In: Hamblin MR, Waynant RW, Anders J, editors. Mechanisms for Low-Light Therapy, January 22 and 24, 2006, San Jose, Calif. Proc. SPIE Bellingham, Wash.: SPIE The International Society for Optical Engineering, 2006: Karu T. Primary and secondary mechanisms of action of visible to near-ir radiation on cells. J Photochem Photobiol B 1999;49(1): Robertson CA, Hawkins Evans D, Abrahamse H. Photodynamic therapy (PDT): A short review on cellular mechanisms and cancer research applications for PDT. J Photochem Photobiol B 2009;96(1): Maisch T. A new strategy to destroy 12. Blum HF. Photodynamic action and diseases caused by light. New York: Reinhold Publishing Corporation, Spikes JD, Livingston R. The molecular biology of photodynamic action: Sensitized photoautooxidations in biological systems. In: Augenstein LG, Mason R, Zelle M, editors. Advances in radiation biology, vol. 3. New York: Academic Press, 1969: Santamaria L, Prino G. List of the photodynamic substances. In: Gallo U, Santamaria L, editors. Research progress in organic, biological and medicinal chemistry, volume 3, part I. Amsterdam: North-Holland Publishing Company, 1972:xi-xxxv. 15. Marotti J, Aranha AC, Eduardo Cde P, Ribeiro MS. Photodynamic therapy can be effective as a treatment for herpes simplex labialis. Photomed Laser Surg 2009;27(2): Schuller DE, McCaughan JS Jr, Rock RP. Photodynamic therapy in head and neck cancer. Arch Otolaryngol 1985;111(6): Wood S, Metcalf D, Devine D, Robinson C. Erythrosine is a potential photosensitizer for the photodynamic therapy of oral plaque biofilms. J Antimicrob Chemother 2006;57(4): Kübler AC. Photodynamic therapy. Med Laser Appl 2005;20(1): Dörtbudak O, Haas R, Bernhart T, Mailath-Pokorny G. Lethal photosensitization for decontamination of implant surfaces in the treatment of peri-implantitis. Clin Oral Implants Res 2001;12(2): Takasaki AA, Aoki A, Mizutani K, Schwarz F, Sculean A, Wang C-Y, Koshy G, Romanos G, Ishikawa I, Izumi Y. Application of antimicrobial photodynamic therapy in periodontal and peri-implant diseases. Periodontol ;51(1): JOURNAL OF LASER DENTISTRY 2009 VOL 17, NO. 3 Parker 137

30 CLINICAL REVIEW AND CASE REPORTS 26. Gomer CJ, Luna M, Ferrario A, Wong S, Fisher AMR, Rucker N. Cellular targets and molecular responses associated with photodynamic therapy. J Clin Laser Med Surg 1996;14(5): Moan J, Berg K. The photodegradation of porphyrins in cells can be used to estimate the lifetime of singlet oxygen. Photochem Photobiol 1991;53(4): Girotti AW. Photosensitized oxidation of membrane lipids: Reaction pathways, cytotoxic effects, and cytoprotective mechanisms. J Photochem Photobiol B 2001;63(1-3): Darveau RP, Tanner A, Page RC. The microbial challenge in periodontitis. Periodontol ;14(1): Feres M, Haffajee AD, Allard K, Som S, Goodson JM, Socransky SS. Antibiotic resistance of subgingival species during and after antibiotic therapy. J Clin Periodontol 2002;29(8): Slots J, Rams TE. Antibiotics in periodontal therapy: Advantages and disadvantages. J Clin Periodontol 1990;17(7 Pt II): Walker CB. The acquisition of antibiotic resistance in the periodontal microflora. Periodontol ;10(1): Levy SB. Antimicrobial resistance: Bacteria on the defence. Resistance stems from misguided efforts to try to sterilise our environment [editorial]. BMJ 1998;5;317(7159): Levy SB. Factors impacting on the problem of antibiotic resistance. J Antimicrob Chemother 2002;49(1): Prophylaxis against infective endocarditis. Antimicrobial prophylaxis against infective endocarditis in adults and children undergoing interventional procedures. NICE clinical guideline 64. London: National Institute for Health and Clinical Excellence, [Cited 2010 Jan 3.] 107 p. Available from: Guidance/pdf/English. 36. Russell AD. Lethal effects of heat on bacterial physiology and structure. Sci Prog 2003;86(1-2): Wainwright M, Crossley KB. Methylene blue A therapeutic dye for all seasons? J Chemother 2002;14(5): Meisel P, Kocher T. Photodynamic therapy for periodontal diseases: State of the art. J Photochem Photobiol B 2005;79(2): Polansky R, Haas M, Heschl A, Wimmer G. Clinical effectiveness of photodynamic therapy in the treatment of periodontitis. J Clin Periodontol 2009;36(7): Christodoulides N, Nikolidakis D, Chondros P, Becker J, Schwarz F, Rössler R, Sculean A. Photodynamic therapy as an adjunct to nonsurgical periodontal treatment: A randomized, controlled clinical trial. J Periodontol 2008;79(9): Andersen R, Loebel N, Hammond D, Wilson M. Treatment of periodontal disease by photodisinfection compared to scaling and root planing. J Clin Dent 2007;18(2): de Almeida JM, Theodoro LH, Bosco AF, Nagata MJH, Oshiiwa M, Garcia VG. In vivo effect of photodynamic therapy on periodontal bone loss in dental furcations. J Periodontol 2008;79(6): Walsh LJ. The current status of laser applications in dentistry. Aust Dent J 2003;48(3): Bonsor SJ, Nichol R, Reid TMS, Pearson GJ. Microbiological evaluation of photo-activated disinfection in endodontics (An in vivo study). Br Dent J 2006;200(6): Braun A, Dehn C, Krause F, Jepsen S. Short-term clinical effects of adjunctive antimicrobial photodynamic therapy in periodontal treatment: A randomized clinical trial. J Clin Periodontol 2008;35(10): Konopka K, Goslinski T. Photodynamic therapy in dentistry. J Dent Res 2007;86(8): Hayek RRA, Araújo NS, Gioso MA, Ferreira J, Baptista-Sobrinho CA, Yamada AM Jr, Ribeiro MS. Comparative study between the effects of photodynamic therapy and conventional therapy on microbial reduction in ligature-induced periimplantitis in dogs. J Periodontol 2005;76(8): Donnelly RF, McCarron PA, Tunney MM, David Woolfson A. Potential of photodynamic therapy in treatment of fungal infections of the mouth. Design and characterisation of a mucoadhesive patch containing toluidine blue O. J Photochem Photobiol B 2007;86(1): Cassidy CM, Tunney MM, McCarron PA, Donnelly RF. Drug delivery strategies for photodynamic antimicrobial chemotherapy: From benchtop to clinical practice. J Photochem Photobiol B 2009;95(2): Hayek RRA, Araújo NS, Giosi MA, Ferreira J, Baptista-Sobrinho CA, Yamada AM Jr, Ribeiro MS. Comparative study between the effects of photodynamic therapy and conventional therapy on microbial reduction in ligature-induced periimplantitis in dogs. J Periodontol 2005;76(8): Parker

31 CLINICAL RESEARCH Biostimulation Effects of Superpulsed, High-Intensity, Low-Average Power Laser Application on the Timing of Orthodontic Aligner Sequencing of the Invisalign System Nelson Marquina, MSc, PhD, DC 1 ; Fred Stalley, DDS 2 1 USA Laser Biotech Inc., Richmond, Virginia, United States 2 Redondo Beach Dental Group, Redondo Beach, California, United States J Laser Dent (3): INTRODUCTION The scientific rationale behind orthodontic movement of teeth began more than100 years ago with a book by Sandstedt that was subsequently published as a three-part article in 1904 and Sandstedt constructed a unique experimental model in which the six maxillary incisors of a dog were attached to an appliance and moved 3 mm into the lingual direction within a three-week period. His histological analysis revealed that bone had formed on the alveolar wall of the tension side of the tooth, where the newly formed bone spicules were in the same alignment as the periodontal ligament fibers. These findings were consistent with the application of both light and heavy orthodontic forces. On the pressure side, however, he found that bone was resorbed by osteoclastic activity (as evidenced by the presence of Howship lacunae) with light orthodontic forces, and found certain cell-free areas (as a result of capillary thrombosis and cell death) which he referred to as hyalinization zones under heavy orthodontic forces (Figures 1-2). It was hypothesized that some form of molecular signaling mechanism was responsible for the mechanotransduction which stimulates osteoblasts to generate newly formed bone and osteoclasts to resorb bone. The necessity of mechanical stimuli for the proper maintenance of bone in ABSTRACT Purpose: The aim of this study was to ascertain the biostimulatory effects of a superpulsed, high-intensity laser on the bone remodeling cycle under load of orthodontic forces. Furthermore, this study tested whether the bone remodeling process can be accelerated enough in order to show a clinically significant reduction of the timing between aligner changes of the Invisalign system (Align Technology, Inc., Santa Clara, Calif.), referred to below as the orthodontic system. Background: It is common knowledge that bone, as an organ, will respond to pressure above a certain threshold with remodeling. In orthodontic applications, the type of remodeling response will depend on whether bone is under compression (direction of tooth movement) or under tension (the side opposite the direction of movement). On the compression side, the periodontal ligament (PDL) fibers are compressed, which initiates a signaling cascade leading to osteoclastic resorption of bone. On the tension side, the stretching of the periodontal ligament fibers appears to promote osteoblast-mediated bone proliferation. Research has also shown that biostimulation light energy from a low-average power laser can have a stimulating and acceleratory effect on tissue regeneration by promoting an increase in cell populations and signaling molecules responsible for the tissue regeneration and repair cycle. With this information, it stands to reason that laser-induced accelerated bone remodeling will also effectively accelerate the orthodontic movement of teeth without an increase of the orthodontic force applied. Methods: Forty patients undergoing orthodontic system treatment were selected for this study. These patients were randomly divided into two groups of 20 patients: GL, which received laser treatment, and GC, which served as a control. Each patient was instructed to wear the aligners for a minimum of 20 hours per day. Each patient in GL presented for phototherapy twice a week with at least two days between each of the phototherapy sessions. GC presented for progress checks once a week. Phototherapy was conducted with a superpulsed, high pulse power, and low-average power 910-nm GaAs laser. Tracking progress of all moving teeth for both groups was evaluated at every appointment, during which the computerized progression model was compared to the actual in vivo alignment. Once the in vivo alignments of the teeth matched the computer model for a particular aligner, the aligner was switched to the next in sequence. Results: At the termination of the study GL had statistically significant fewer days between aligner exchanges (mean = 9.6 days) than GC (mean = 14.6 days). Marquina and Stalley 139

32 CLINICAL RESEARCH Figure 1: Sandstedt s histological section showing the pressure side after mild force application in the canine model. Ab, active bone; Rb, resorptive bone; Pl, periodontal ligament; Rs, root surface. One can clearly recognize numerous osteoclasts in multiple Howship lacunae. (From Sandstedt CE. Några bidrag till tandregleringens teori [Some contributions to the dental association rules theory]. Stockholm: Kungle Boktrycheriet/Nordstedt & Söner, 1901) Figure 2: Sandstedt s histological section of the tension side. De, dentin; Ce, cementum; Pl, periodontal ligament; Nb, new bone; Bj, old bone junction; Cb, compact bone. One can clearly see how the newly formed osteoblasts are oriented along the stretched fibers of the ligament. (From Sandstedt CE. Några bidrag till tandregleringens teori [Some contributions to the dental association rules theory]. Stockholm: Kungle Boktrycheriet/Nordstedt & Söner, 1901) the skeletal system had already been recognized since the middle of the 19th century. 3-4 Moreover, Frost reported that the bone tissue within the human skeleton is continuously being remodeled by the tightly orchestrated interaction of osteoclasts resorbing old bone and osteoblasts forming new bone. 5 More than 100 years after Sandstedt s publication, more detailed knowledge has been gained of the signaling cascades which lead from the mechanical deformation of the periodontium to either osteogenesis or bone resorption. An examination of the basic molecular architecture of cell attachments will help illuminate this pathway. Cells such as osteoblasts or fibroblasts have integral membrane proteins which interact with the extracellular matrix (ECM) and mediate a variety of intracellular signals or attach to other cells. These integral membrane proteins are thus classified as cell surface receptors and collectively referred to as integrins. It has been shown that numerous signaling pathways can be activated by integrins, which sense a mechanical distortion between the cytoskeletal elements they are attached to the inside of a cell and the ECM attachment outside the cell. Basdra et al. showed that concentration levels of integrin-mediated signaling proteins (rab and rho guanosine triphosphatases) were altered in mechanically stretched PDL fibroblasts, 6 and Peverali et al. have shown similar results for the mitogen-activated protein kinase family in osteoblasts. 7 Harell et al. suggested in 1977 that a specific sequence of molecular events is initiated in osteoblast-like cells undergoing mechanical deformation in an in vitro environment. 8 During this sequence of events adelynate cyclase is activated, leading to a transient increase of cyclic adenosine monophosphate (camp), an increase intracellular [Ca++], and the initiation of DNA synthesis and mitosis, 9 thereby initiating a repair process, as Ngan et al. reported in their in vitro study involving human gingival fibroblasts. In summary, DNA synthesis, mitosis, and cell differentiation of fibroblasts and osteoblasts are a direct result of a shift in mechanical pressures within the PDL space. Furthermore, recent in vitro studies have shown that lowaverage power laser light can stimulate and enhance the proliferation and differentiation of bone marrow stem cells (BMSCs) as well as increase the secretion of growth factors The biostimulatory effects of certain nonablative lasers have been reported in the literature of the late 1960s and early 1970s Since then, numerous publications have elevated phototherapeutic laser applications into mainstream medicine and dentistry Laser energy interacts with tissues through chromophores. Chromophores are parts of the molecule responsible for its color. In biological molecules that serve to absorb or detect light energy, the chromophore is the moiety that causes a conformational change of the molecule when hit by light. Water is one of the most predominant chromophores in human tissue, capable of absorbing light in various amounts throughout the infrared spectrum where dental lasers operate. 26 However, between approximately 600 and 1000 nm, there is a narrow bandwidth in which the absorptive power of water is greatly reduced, and infrared light can penetrate deeply into tissues Virtually all phototherapeutic lasers today have emissions within the 600-to-1000 nm spectral range. The basis of the biostimulatory effects of phototherapeutic lasers is actually a synergistic amalgamation of two separate effects: The photochemical effect, in which the photon energy of the laser is absorbed by cytochrome-c oxidase, a large transmembrane protein found in the mitochondrial cell 140 Marquina and Stalley

33 CLINICAL RESEARCH wall. This will cause a short-term activation of the respiratory chain in which the resulting changes of redox states of the mitochondrial plasma and membrane help establish a chemiosmotic potential that the adenosine triphosphate (ATP)- synthase enzyme then uses to synthesize ATP. 29 This sudden increase in ATP within cells will lead to the ability to not only initiate but also accelerate the physiology of irradiated tissues. The photomechanical effect, in which the photons from a highintensity, low-average power, pulsed laser interact with the target tissues to promote gene expression. 16, 30 Gene expression is an important step during the transformatory phase of mesenchymal stem cells into osteoprogenitor cells such as osteoblasts. When these biochemical effects of laser therapy are considered, it stands to reason that, with the correct laser dosage and wavelength, bone remodeling is one of the cellular processes that can be accelerated in an in vivo environment. Bone remodeling is the cornerstone of the translation of teeth in the orthodontic process. Consequently, our hypothesis was that properly dosed laser therapy can accelerate the bone remodeling, initiated through mechanical force changes around teeth, and thus accelerate the orthodontic movement of teeth, given a constantly applied pressure. SELECTION CRITERIA This investigation was characterized as a Phase I study with less than 50 subjects. Selection criteria included men and women between the ages of 20 and 40 who were candidates for the orthodontic movement of teeth utilizing the specific orthodontic system identified above. Participation was strictly voluntary. The Institutional Review Board from Texas Applied Biomedical Services (Houston, Texas) approved the study protocol. Patients who qualified for this research project were properly informed of the system s procedure, biostimulatory laser therapy, as well as the associated risks and benefits. In addition, alternative treatment modalities and their associated risks and benefits were discussed. A brief synopsis of the research project its goals, expectations, and possible benefits was also given to each patient. Exclusion criteria were as follows: Patients under the age of 20 and over the age of 40 were not considered in order to obtain a more homogeneous population sample. Patients with potential neoplasms in the head-and-neck region were excluded, since a possibility exists that laser application might accelerate carcinogenesis in patients suffering from such pathologies, although there is currently no research demonstrating such clinical effects. Patients who were smokers were excluded because nicotine has a very strong vasoconstricting effect on microvasculature and may interfere with the normal regeneration process of bone. Patients who were undergoing bisphosphonate therapy were excluded since studies are emerging that indicate cancer patients being treated with bisphosphonates may be at risk for osteonecrosis of the jaw. 31 MATERIALS AND METHODS Each potential research subject was screened and categorized as eligible or not eligible based on the inclusion and exclusion criteria identified above. The orthodontic system takes advantage of the dramatic developments in CAD/CAM technology in recent years A patient s impression is scanned to produce a computerized three-dimensional image of the initial alignment of teeth. The desired final alignment is done virtually with computer software and then translated into a sequence of aligner trays which are necessary to achieve that goal. The number of aligners necessary for a case will vary from patient to patient and can be as few as 10 and as many as 40. The Invisalign protocol calls for aligner change every 14 days, if the alignment of the teeth in vivo matches the alignment of the teeth on the computer model (ClinCheck 2.6 software, Align Technology, Inc., Santa Clara, Calif.). Those subjects who were selected were randomly assigned to one of two groups of 20 individuals each: Group L (GL): Patients received the orthodontic system and also presented twice a week for laser treatments and progress checks, with at least two days between laser treatments. Group C (GC): Patients received the orthodontic system only, and presented weekly for progress checks only. Each patient was instructed to wear the aligners for a minimum of 20 hours per day. Progress checks were performed with ClinCheck, which displays a three-dimensional image of the dentition within each aligner sequence. Individual tooth positions were measured in relation to adjacent teeth with the help of a millimeter grid overlay in the software (Figure 3). Figure 3: A typical example of an Invisalign case analysis. The overlay grid is used to measure distances and angulations of individual teeth to each other, which is then compared to the intraoral environment Marquina and Stalley 141

34 CLINICAL RESEARCH These measurements were synchronized in vivo with a periodontal probe (Hu-Friedy, Chicago, Ill.) for each tooth that was being moved orthodontically. The computer model measurements were then compared to the intraoral measurements. If the intraoral alignments of the teeth matched the computer model, the patient was given the next aligner in the sequence. These progress checks were conducted for both groups. Laser treatments were performed with a free-running, pulsed 910-nm GaAs laser (Lumix 2, USA Laser Biotech Inc., Richmond, Va.). The laser was used at 45 Watts peak power at 30 KHz for this study. The diameter of the emitter tip is 8 mm and has a divergence angle of 12 degrees. Each arch was divided into six illumination spots, three on each side of the arch, so that there was slight overlap between the illuminated areas to cover the whole arch (Figure 4). Each of the six spots was illuminated for 90 seconds, for a total duration of 9 minutes per arch. This translates into 27 joules of energy per spot and 162 joules per arch. The emitter tip was held at approximately 5 mm from the buccal surfaces, just apical to the cementoenamel junction (CEJ) (Figure 5). Once the patients completed their aligner sequence, the following data were collected: Total number of aligners used Average number of days between aligner switches Number of midcourse corrections (additional trays used to correct abnormal tracking of teeth in midcourse). Statistical analysis was done with the SPSS statistical software (PASW Statistics 18.0, SPSS Inc., Chicago, Ill.). RESULTS Both, the laser group (GL) and the control group (GC) samples consisted of 20 patients each. The longest and shortest treatment course for GL was 240 days and 99 days, respectively. The longest and shortest treatment course for GS Figure 4: Six areas of laser illumination were used to cover the entire maxillary arch, and six areas were also used for the mandibular arch. Each of these areas received 90 seconds worth of exposure. This image shows the illumination pattern for the maxillary arch was 425 days and 143 days, respectively. The average number of aligners needed to complete the case was 18.1 for GL and for GC, which was not statistically different at a significance level alpha of The average number of days between aligner exchanges was 9.57 for GL and for GC, which produced statistically highly significant results using a one-tailed t-test P value of at an alpha level of Therefore, the laser group had a 34.6% faster aligner sequencing. Furthermore, of the 20 subjects in the control group, 5 needed midcourse corrections, whereas only 3 subjects needed midcourse corrections in the laser group (Table 1). On a subjective side note, patients in the laser treatment group reported fewer complaints of moderate-tosevere soreness the first two days after a new aligner had been fitted than the patients in the no laser treatment (control) group. DISCUSSION Teeth move in a certain direction by applying pressure on the teeth in the direction of translation. This will cause a deformity of the PDL on the pressure side as well as the tension side of the individual teeth. The deformation of certain cells in the PDL environment (fibroblasts and Figure 5: The emitter portion of the laser is directed toward the buccal surfaces of the roots just apical to the cementoenamel junction osteoblasts) is sensed by the integrins in their cell wall, which then release specific signaling molecules to activate the remodeling process. This process is called mechanotransduction. Some of these integrin-mediated signaling proteins (rab and rho guanosine triphosphatases, and mitogen-activated protein kinase) cause the proliferation of osteoclasts on the pressure side of the teeth and proliferation of osteoblasts on the tension side of the teeth. Furthermore, other signaling molecules will initiate an inflammatory reaction and mesenchymal stem cell division and transformation as part of the healing response. All of these cellular processes are energy-intensive activities for cells, especially DNA synthesis, mitosis, and transformation of stem cells into new fibroblasts or osteoblasts. The basic energy molecule for all cells is adenosine triphosphate (ATP). 36 Cells use this molecule to power their various activities. If a particular cell lacks sufficient quantities of ATP, certain cellular activities cannot take place. A sufficient quantity of ATP is therefore the prerogative for various cellular activities, especially in the repair and remodeling process of bone. Phototherapy laser energy has been shown to increase the rate of cell division, cell transformation (mesenchymal stem cells), production of signaling molecules, and development of osteoblasts, fibroblasts, and osteoclasts. 37 All of these cellular 142 Marquina and Stalley

35 CLINICAL RESEARCH Orthodontic System Data with Biostimulatory Laser Application Orthodontic System Data without Biostimulatory Application Subject Total Number of Aligners events are involved in the bone remodeling processes of orthodontic movement of teeth. It is therefore a reasonable assumption that a lowaverage power laser can also accelerate the rate of tooth movement in the orthodontic process. As previously mentioned, of the two groups that were studied, the laser group showed a faster aligner sequencing. One can speculate, based on the information given above, that the chromophores of the cells in question were able to absorb the photon energy of the laser and convert this energy into their own usable energy in the form of ATP. This process is governed by very specific pathways; in particular, the main chromophore in the mitochondria is the protein molecule cytochrome-c oxidase, which is a Average Days Between Aligners Number of Midcourse Corrections Subject component of the respiratory chain. It is the terminal enzyme that mediates the transfer of electrons from cytochrome-c to molecular oxygen. Additionally, ferrocytochrome-c is oxidized, dioxygen is reduced, and protons are pumped from the mitochondria to the cytosol. 36 The electrochemical potential generated across the inner membrane of the mitochondrion by this redox drives the oxidative photophosphorylation of ADP into ATP. 36 Once the concentration of ATP had increased inside the cells, they were able to initiate and execute the remodeling cascade with more efficiency and speed. It is our hypothesis that these were the most predominant precipitating factors in the accelerated tray sequencing we observed in the laser group. Indeed, there are studies Total Number of Aligners Average Days Between Aligners Number of Midcourse Corrections S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S Mean 9.57 Days Mean Days Table 1: This table shows the data distribution of all 40 subjects in both groups. Group GL is the table on the left side and group GC is on the right side. The results show a statistically significant difference between GL and GC with respect to the actual days between aligner exchanges and the recommended 14 days. using rats as well as one using a group of 15 patients 40 that demonstrate how a low average power laser can contribute to a more rapid movement of teeth. C ONCLUSION Within the confines of this study we have shown that low-average power, high-pulse intensity laser phototherapy can potentially accelerate orthodontic movements of teeth for the Invisalign platform. Future studies should compare these results with variations in wavelength, energy deliverance, and exposure durations. The limitation of this study was the small sample size. Larger-scale studies need to be done, perhaps on a multicenter level, in order to confirm and expand these results. It is our opinion that Marquina and Stalley 143

36 CLINICAL RESEARCH this study is synergistic to the evergrowing body of evidence showing that low-power laser phototherapy may have a positive effect on overall healing, since the molecular healing cascade is similar for various tissue types in the human body. AUTHOR BIOGRAPHIES Dr. Nelson Marquina is the president of USA Laser Biotech Inc., a medical device developer focused on lasers and bioelectromagnetic devices for USA and Canadian markets. He has earned a Master of Science degree in statistics from Worcester Polytechnic Institute and doctoral degrees in systems engineering from the University of Houston and in chiropractic medicine from Logan University. He is an adjunct associate professor of biophysics at Virginia State University and a consultant to the National Foundation for Alternative Medicine (Washington, D.C.). Dr. Marquina is a former senior scientist at NASA/Johnson Space Center (Texas) and Director of Research at Logan University (Chesterfield, Mo.). He was Director of Information Systems in Mars, Inc. (New Jersey) and former partner in Coopers & Lybrand s Information Technology Consulting Services (New York, N.Y.). He is an executive, consultant, and educator with more than 25 years of combined management, teaching, and technical experience in information systems, statistical analysis, and bioelectrical and bioelectromagnetic systems. Dr. Marquina is also a developer of bioelectrical, biophotonics, and bioelectromagnetic systems and their treatment protocols. He has chaired national conferences in computer expert systems, high technology in alternative medicine, and computer vision. He can be reached at Marquina@comcast.net. Disclosure: Dr. Marquina is a paid consultant to Harris Medical Resources and BEMER USA. He is a stockholder in USA Laser Biotech Inc. Dr. Fred Stalley is a private practitioner based in Redondo Beach, Calif. He received his dental degree in 1979 from the University of Southern California. He specializes in cosmetic and implant dentistry and is a graduate of the Las Vegas Dental Institute. He is also member of the Academy of Osseointegration, the American Academy of Implant Dentistry, the International Congress of Oral Implantologists, and the American Academy of Cosmetic Dentistry. He has been utilizing laser technology since Dr. Stalley has lectured nationwide as well as abroad. He can be reached at rbdg@redondobeachdentalgroup.com. Disclosure: Dr. Stalley has nothing to disclose relative to this manuscript. R EFERENCES 1. Sandstedt CE. Några bidrag till tandregleringens teori [Some contributions to the dental association rules theory]. Stockholm: Kungle Boktrycheriet/Nordstedt & Söner, Swedish. 2. Sandstedt C. Einige beiträge zur theorie der zahnregulierung. Nord Tandläk Tidskr 1904;5: ; 1905;6:1-25; 1905;6: German. 3. Meyer GH. Die architektur der spongiosa. (Zehnter beitrag zur mechanic des menschlichen knochengerüstes.) Arch Anat Physiol Wiss Med 1867;47: German. 4. Wölff JD. Das gesetz der transformation der knochen. Berlin: Verlag von August Hirschwald, German. Also see Julius Wolff. The law of bone remodeling. Maquet P, Furlong R, translators. Berlin: Springer-Verlag, Frost HM. Bone remodeling dynamics. Springfield, Ill.: Charles C Thomas, Basdra EK, Papavassiliou AG, Huber LA. Rab and rho GTPases are involved in specific response of periodontal ligament fibroblasts to mechanical stretching. Biochim Biophys Acta 1995;1268(2): Peverali FA, Basdra EK, Papavassiliou AG. Stretch-mediated activation of selective MAPK subtypes and potentiation of AP-1 binding in human osteoblastic cells. Mol Med 2001;7(1): Harell A, Dekel S, Binderman I. Biochemical effect of mechanical stress on cultured bone cells. Calcif Tissue Res 1977;22(Suppl 1): Ngan PW, Crock B, Varghese J, Lanese R, Shanfeld J, Davidovitch Z. Immunohistochemical assessment of the effect of chemical and mechanical stimuli on camp and prostaglandin E levels in human gingival fibroblasts in vitro. Arch Oral Biol 1988;33(3): Mvula B, Mathope T, Moore T, Abrahamse H. The effect of low level laser irradiation on adult human adipose derived stem cells. Lasers Med Sci 2008;23: Mvula B, Moore TJ, Abrahamse H. Effect of low-level laser irradiation and epidermal growth factor on adult human adipose-derived stem cells. Lasers Med Sci. Epub 2009 Jan 27. DOI /s Hou J-F, Zhang H, Yuan X, Li J, Wei Y-J, Hu S-S. In vitro effects of lowlevel laser irradiation for bone marrow mesenchymal stem cells: Proliferation, growth factors secretion and myogenic differentiation. Lasers Surg Med 2008;40(10): Eduardo Fde P, Bueno DF, de Freitas PM, Marques MM, Passos- Bueno MR, Eduardo Cde P, Zatz M. Stem cell proliferation under low intensity laser irradiation: A preliminary study. Lasers Surg Med 2008;40(6): de Souza SC, Munin E, Alves LP, Salgado MAC, Pacheco MTT. Low power laser radiation at 685 nm stimulates stem-cell proliferation rate in Dugesia tigrina during regeneration. J Photochem Photobiol B 2005;80(3): Tuby H, Maltz L, Oron U. Low-level laser irradiation (LLLI) promotes proliferation of mesenchymal and cardiac stem cells in culture. Lasers Surg Med 2007;39(4): Marquina and Stalley

37 CLINICAL RESEARCH 16. Stein E, Koehn J, Sutter W, Wendtlandt G, Wanschitz F, Thurnher D, Baghestanian M, Turhani D. Initial effects of lowlevel laser therapy on growth and differentiation of human oseoblastlike cells. Wien Klin Wochenschr 2008;120(3-4): Carney SA, Lawrence JC, Ricketts CR. The effect of light from a ruby laser on the metabolism of skin in tissue culture. Biochim Biophys Acta 1967;148(2): Mester E, Spiry T, Szende B, Tota JG. Effect of laser rays on wound healing. Am J Surg 1971;122(4): Wang GH, Jiang SJ, Hu SJ, Zheng GC, Peng SY. A study of the analgesic effect of low power He-Ne laser and its mechanism by electrophysiological means. In: Yamamoto H, Atsumi K, Kusakari H, editors. Lasers in dentistry. Proceedings of the International Congress of Laser in Dentistry, August 5-6, 1988, Tokyo, Japan. Amsterdam: Excerpta Medica, 1989: Walsh LJ. The current status of low level laser therapy in dentistry. Part 1. Soft tissue applications. Aust Dent J 1997;42(4): Walsh LJ. The current status of low level laser therapy in dentistry. Part 2. Hard tissue applications. Aust Dent J 1997;42(5): Hopkins JT, McLoda TA, Seegmiller JG, David Baxter G. Low-level laser therapy facilitates superficial wound healing in humans: A triple-blind, sham-controlled study. J Athl Train 2004;39(3): Hawkins D, Houreld N, Abrahamse H. Low level laser therapy (LLLT) as an effective therapeutic modality for delayed wound healing. Ann N Y Acad Sci 2005;1056: Khadra M. The effect of low level laser irradiation on implant-tissue interaction. In vivo and in vitro studies. Swed Dent J Suppl 2005;172: Parker S. Low-level laser use in dentistry. Br Dent J 2007;202(3): Manni JG. Dental applications of advanced lasers (DAAL tm ). Burlington, Mass.: JGM Associates, Inc., 2004: Karu T. The science of low-power laser therapy. Amsterdam: OPA (Overseas Publishers Association), 1998: Peavy GM. Lasers and laser-tissue interaction. Vet Clin North Am Small Anim Pract 2002;32(3): , v-vi. Erratum in: Vet Clin North Am Small Anim Pract 2002;32(6):ix. 29. Hamblin MR, Demidove TN. Mechanisms of low level light therapy. In: Hamblin MR, Waynant RW, Anders J, editors. Mechanisms for Low-Light Therapy, January 22 and 24, 2006, San Jose, Calif. Proc. SPIE Bellingham, Wash.: SPIE The International Society for Optical Engineering, 2006: Moriyama Y, Nguyen J, Akens M, Moriyama EH, Lilge L. In vivo effects of low level laser therapy on inducible nitric oxide synthase. Lasers Surg Med 2009;41(3): Maerevoet M, Martin C, Duck L. Osteonecrosis of the jaw and bisphosphonates [correspondence]. N Eng J Med 2005;353(1):99-102; discussion Bishop A, Womack WR, Derakhshan M. An esthetic and removable orthodontic treatment option for patients: Invisalign. Dent Assist 2002;71(5): Melkos AB. Advances in digital technology and orthodontics: A reference to the Invisalign method. Med Sci Monit 2005;11(5):PI39-P Wong BH. Invisalign A to Z. Am J Orthod Dentofacial Orthop 2002;121(5): Norris RA, Brandt DJ, Crawford CH, Fallah M. Restorative and Invisalign : A new approach. J Esthet Restor Dent 2002;14(4): Karu T. Primary and secondary mechanisms of action of visible to near-ir radiation on cells. J Photochem Photobiol B 1999;49(1) Karu T. Ten lectures on basic science of laser phototherapy. Grängesberg, Sweden: Prima Books, Kawasaki K, Shimizu N. Effects of low-energy laser irradiation on bone remodeling during experimental tooth movement in rats. Lasers Surg Med 2000;26(3): Ozawa Y, Shimizu N, Kariya G, Abiko Y. Low-energy laser irradiation stimulates bone nodule formation at early stages of cell culture in rat calvarial cells. Bone 1998;22(4): Youssef M, Ashkar S, Hamade E, Gutknecht N, Lampert F, Mir M. The effect of low-level laser therapy during orthodontic movement: A preliminary study. Lasers Med Sci 2008;23(1): Marquina and Stalley 145

38 TRIBUTE Professor Endre Mester, the Father of Photobiomodulation Professor Lajos Gáspár, DDS, PhD, Budapest, Hungary J Laser Dent 2009;17(3): Editor s Note: During a recent visit to Romania to attend a conference, Dr. Steven Parker met with Professor Lajos Gáspár, an ALD member from Hungary. Both were invited speakers at the meeting and their discussions led to the recognition of the undisputed place of Professor Endre Mester ( ) in the development of low-level laser application in medicine. Inspired by the work of Professor Mester, Professor Gáspár is credited with the first Hungarian PhD thesis in the field of laser research. In his own country, Professor Gáspár has pioneered the introduction of both high-power and low-power lasers in oral and dental surgery. The following reflects Professor Gáspár s intimate association with Professor Mester s family and provides testimony to the impact of Endre Mester as the father of photobiomodulation in low-level laser therapy. Professor Endre Mester, MD, DSc, was born in Budapest, Hungary, in As a schoolboy, he excelled as a violin player and developed an interest in medicine. With such diverse interests, he decided to sit university entrance examinations in both medicine and music. He succeeded in gaining a place to read medicine at the University of Budapest. His continued interest in music was relegated to social enjoyment with friends on weekends. Having successfully completed his undergraduate medical study and graduation, he was invited to receive training in surgery as a resident staff member of the 3rd Department of Surgery at the University of Budapest. He subsequently obtained his first position outside the university as head of children s surgery in St. Steven s Hospital in Budapest. From there, greater recognition beckoned and his next position was head of a major hospital in Budapest, the Bajcsy Zsilinszky. There he combined clinical work with administration, being appointed director of the hospital. During this period, Mester undertook research and scientific work in the field of abdominal surgery, with a special focus on bile duct surgery. His interest in the Professor Endre Mester, MD, DSc ( ) latter led to his gaining his PhD. Promotion led to his full professorship and Director of the 2nd Department of Surgery of Semmelweis University in Budapest and election as President of the Society of Hungarian Surgeons. At Semmelweis, Mester started laser research in 1965; this was five years after the development of the first laser by Theodore H. Maiman 1 and only two years after surgical laser applications had been pioneered by notable workers such as Paul E. McGuff 2 and Leon Goldman. 3-4 Like others of his era, Mester attempted to use a high-power laser to destroy malignant tumors. Early in his experiments, he implanted tumor cells beneath the skin of laboratory rats and exposed them to a customized ruby laser, based on Maiman s earlier model. To his surprise, the tumor cells were not destroyed by doses of what was presumed to be highpower laser energy. Instead, it was observed that in many cases the skin incisions made to implant the abnormal cells appeared to heal faster in treated animals, compared to incisions of control animals that were not treated with light. 5 Mester was baffled as to how a device that was intended to destroy tumor cells had instead promoted tissue repair. His custom-designed ruby laser was weak and certainly not as powerful as he thought it to be. Instead of being photo-ablative, the low-power light had no effect on the tumor. Indeed, it stimulated the skin to heal faster. This fortuitous encounter opened the field of monochromatic light treatment. This casual observation led him to design an experiment to ascertain his suspicion that treatment with red light accelerated healing of the surgical skin incisions he made to implant the cells. The experiment was successful as it showed that treatment with red light indeed produced faster healing of the skin wounds. Baffled but fascinated by this development, he carried out 146 Gáspár

39 TRIBUTE other experiments in which he showed that experimental skin defects, burns, and human cases of ulcers arising from diabetes, venous insufficiency, and infected wounds also healed faster in response to his laser treatment. 5-7 In direct opposition of contemporary theory that the future of lasers lay solely in the domain of resective surgery, Mester had discovered a new application of laser energy repeated low-intensity laser irradiation to determine radio-biological effects. He was the first to describe the biostimulation effect of lasers. Following his earlier observations on skin, he developed studies into accelerated healing: hair growth in mice, where depilated skin was prepared for such irradiation studies, appeared to be faster after exposure to laser energies as low as 1 Joule/cm 2 per day. 8 Experimental research into laser biostimulation continued most actively during a period of 6 years and Mester was awarded a Scientific Doctorate by the Hungarian Academy of Sciences in recognition of his work. His experimental studies showed that many different beneficial effects associated with healing might be due to photobiostimulation. Mester measured effects of different laser doses on the mucosal surface of dog s intestinal mucosa. He proved fibroblast activation led to increased collagen production. During healing of vasculitis ulcers in rheumatoid arthritis patients, he observed anti-inflammatory and pain-decreasing effects as well. Measurement of increased phagocytosis in granulocytes was shown to be directly due to the effects of his low-level ruby laser. These observations promoted in vitro studies of lymphocytes, where systemic immunological effects were proved. He organized large numbers of collaborator researchers to undertake widespread studies. Results showed different laser effects on anti-inflammatory versus proinflammatory prostaglandins, resulting in decreased inflammation. Since Mester first uncovered the therapeutic value of red light, different wavelengths of light have been shown to promote healing of skin, muscle, nerve, tendon, cartilage, bone, and dental and periodontal tissues In studies, when healing appears to be impaired, such tissues respond positively to the appropriate doses of light, especially light that is within 600 to 1,000 nm wavelengths. The evidence suggests that low-energy light speeds many stages of healing as it accelerates inflammation, promotes fibroblast proliferation, enhances the synthesis of type I and type III procollagen mrna, quickens bone repair and remodeling, promotes re-vascularization of wounds, and accelerates tissue repair in experimental and clinical models. The inspiration showed by Mester led to many Hungarian workers achieving eminence in the field of low-level laser therapy. His sons Andrew and Adam were coworkers, and Andrew, living in California, published studies about neuro-olfactory biostimulation. Lajos Hazay irradiated urinary bladder ulcers using a low-level laser and a fiber-optic delivery system. Attila Torok began work into duodenal ulcers and treated ulcerative colitis with a similar laser system. Judit Ortutay published rheumatologic studies. Eniko Korchma published results in oral and dental photobiomodulation. Judit Horvath wrote a book about experiences of a general practitioner using low-level lasers. Other notable Hungarian workers have achieved success through Endre Mester: Lajos Kovacs was awarded a Scientific Doctor title with experimental and clinical studies in gynecology Gyorgy Szabo successfully submitted a PhD thesis in earnose-throat biostimulation Klara Barabas achieved a PhD in experimental and clinical doubleblind evaluation of laser treatment of rheumatoid arthritis Timea Berki wrote a PhD thesis about immunological effects of laser irradiation on B-lymphocytes His elder son Adam Mester completed a PhD thesis about laser irradiation of T-lymphocytes. He is currently head of the National Laser Centre for biostimulation-based wound and arthritis healing in Budapest, Hungary. It is inappropriate to consider the development of low-level laser therapy without the acknowledgement of many other international researchers and clinicians. Equally, it is pertinent to record that the basic investigations of Mester into a phenomenon known as biostimulation have shown that, far from active stimulation, many of the processes observed, such as pain suppression, are in fact inhibition. Therefore, it is now customary to look at the area of low-level laser therapy as photobiomodulation (PBM). The Academy of Laser Dentistry is proud of its association with current leaders in the field, such as Jan Tunér and Mary Dyson. The growing interest in PBM in clinical dentistry may lag that shown in other medical disciplines, but opinions are gradually changing in areas outside Eastern Europe and investigations continue to drive the understanding of nonablative, coherent photonic energy as an adjunct to tissue healing. Professor Endre Mester passed away in His legacy is that his unforeseen results obtained using a rudimentary laser device has led to a far-reaching and routine treatment modality that is used in all branches of medicine and dentistry on a daily basis. AUTHOR BIOGRAPHY Dr. Lajos Gáspár is currently an Associated Professor, Head of Ecto Derma Polyclinic at the University Gáspár 147

40 TRIBUTE Educational Center, Budapest, Hungary. He has published 120 articles about lasers and 9 books and 16 book chapters about dentistry, and has given more than 600 presentations. His special honors include: President of the Biomedical Optics Committee of Academy of Sciences Hungary, Secretary General of the Hungarian Medical Laser and Optics Society, National Representative (Hungary) of the World Federation for Laser Dentistry (WFLD) and the International Society for Oral Laser Applications (SOLA). Professor Gáspár can be contacted by at gasparla@t-online.hu. Disclosure: Professor Gáspár has no commercial relationships relative to this manuscript. R EFERENCES 1. Maiman TH. Stimulated optical radiation in ruby. Nature 1960;187(4736): McGuff PE, Bushnell D, Soroff HS, Deterling RA Jr. Studies of the surgical applications of laser (light amplification by stimulated emission of radiation). Surg Forum 1963;14: Goldman L, Blankey DJ, Kindel DJ Jr, Franke EK. Effect of the laser beam on the skin. Preliminary report. J Invest Dermatol 1963;40(3): Goldman L, Blaney DJ, Kindel DJ Jr, Richfield D, Franke EK. Pathology of the effect of the laser beam on the skin. Nature 1963;197(4870): Mester E, Ludány G, Sellyei M, Szende B, Tota J. The simulating effect of low power laser rays on biological systems. Laser Rev 1968;1:3. 6. Mester E, Spiry T, Szende B, Tota JG. Effect of laser rays on wound healing. Am J Surg 1971;122(4): Mester E, Mester AF, Mester A. The biomedical effects of laser application. Lasers Surg Med 1985;5(1): Mester E, Szende B, Tota JG. Lasersugár hatása egerek szorének növekedésére [Effect of laser on hair growth of mice]. Kisérl Orvostud 1967;19: Hungarian. 9. Kana JS, Hutschenreiter G, Haina D, Waidelich W. Effect of low-power density laser radiation on healing of open skin wounds in rats. Arch Surg 1981;116(3): Halevy S, Lubart R, Reuvani H, Grossman N. Infrared (780 nm) low level laser therapy for wound healing: In vivo and in vitro studies. Laser Ther 1997;9: Rezvani M, Robbins MEC, Hopewell JW, Whitehouse EM. Modification of late dermal necrosis in the pig by treatment with multi-wavelength light. Br J Radiol 1993;66(782): Reddy GK, Stehno-Bittel L, Enwemeka CS. Laser photostimulation accelerates wound healing in diabetic rats. Wound Repair Regen 2001;9(3): Mester E, Korényi-Both A, Spiry T, Tisza S. The effect of laser irradiation on the regeneration of muscle fibers (preliminary report). Z Exp Chir 1975;8(4): Shamir MH, Rochkind S, Sandbank J, Alon M. Double-blind randomized study evaluating regeneration of the rat transected sciatic nerve after suturing and postoperative lowpower laser treatment. J Reconstr Microsurg 2001;17(2): Enwemeka CS, Cohen E, Duswalt EP, Weber DM. The biomechanical effects of Ga-As laser photostimulation on tendon healing. Laser Ther 1995;6: Houghton PE, Brown JL. Effect of low level laser on healing of wounded fetal mouse limbs. Laser Ther 1999;11(2): Akai M, Usuba M, Maeshima T, Shirasaki Y, Yasuoka S. Laser s effect on bone and cartilage change induced by joint immobilization: An experiment with animal model. Lasers Surg Med 1997;21(5): Ozawa Y, Shimizu N, Kariya G, Abiko Y. Low-energy laser irradiation stimulates bone nodule formation at early stages of cell culture in rat calvarial cells. Bone 1998;22(4): Loevschall H, Arenholt-Bindslev D. Effect of low level diode laser irradiation of human oral mucosa fibroblasts in vitro. Lasers Surg Med 1994;14(4): Gáspár

41 RESEARCH ABSTRACTS Editor s Note: The following seven abstracts are offered as topics of current interest. Readers are invited to submit to the editor inquiries concerning laser-related scientific topics for possible inclusion in future issues. We ll scan the literature and present relevant abstracts. THE EFFECT OF LOW-LEVEL LASER THERAPY ON GROWTH FACTORS I NVOLVED IN WOUND HEALING Many of the articles in this issue of the Journal discuss wound healing to varying degrees. One generally accepted definition of wound healing identified by Gottrup 1 is a reaction of any multicellular organism to tissue damage in order to restore the continuity and function of the tissue or organ. To be sure, wound healing is a dynamic, continuous, interactive process involving cells and extracellular matrix (material produced by cells and excreted to the extracellular space within tissues), and is dependent on numerous internal as well as external processes. Wound healing may be divided into three phases: inflammation, proliferation or regeneration, and remodeling. Numerous factors affect the entire wound healing process, including individual tissue cells (such as platelets, polymorphonuclear leukocytes, macrophages, fibroblasts, endothelial cells, pericytes or undifferentiated mesenchymal cells, and epithelial cells); blood circulation and oxygenation; infection; presence of foreign bodies; patient characteristics such as age, and indulgences such as smoking and alcohol. An in-depth discussion of wound healing is beyond the scope of this article. One area of laser-related study has been commanding increasing attention in the literature in recent years: the effect of low-level laser irradiation on growth factors involved in wound healing. As described by Storgård Jenson, 1 growth factors are a group of polypeptides involved in cellular chemotaxis (directional movement of a cell in response to a chemical concentration gradient), differentiation, proliferation, and synthesis of extracellular matrix. Further, all wound healing events in soft and hard tissues are affected by growth factors, which can be released from the traumatized tissue, brought to the area by macrophages or neutrophils, or harbored in the blood clot. Growth factors may improve wound healing in numerous ways: Recruit specific cells types and stem cells to the wounded area by chemotaxis Induce differentiation of mesenchymal precursor cells to mature secreting cells Stimulate mitosis of relevant cells, thus increasing proliferation Increase angiogenesis (the formation of new blood vessels) Affect secretion and breakdown of extracellular matrix components. The most significant growth factors involved in the wound healing process, along with some of their primary effects and tissue responses, are summarized below: Platelet Derived Growth Factor (PDGF) stimulates cells proliferation and extracellular matrix production of fibroblasts, contributes to the repair of damaged vascular walls, and activates macrophages to debride the wounded area. Transforming Growth Factors (TGFs), most notably the TGF- subtype, strongly promote extracellular production of many cell types including periodontal ligament fibroblasts, and also help regulate the immune and inflammatory processes. Epidermal Growth Factor (EGF) encourages cells to continue through the cell cycle, thereby promoting proliferation and wound healing. Insulin-like Growth Factor (IGF) combines with other growth factors to stimulate fibroblast proliferation, collagen synthesis, bone formation, and epithelialization. Fibroblast Growth Factors (FGFs) support cell survival under stress conditions and stimulate angiogenesis in the early formation of granulation tissue, and regulate tissue vascularization. Vascular Endothelial Growth Factor (VEGF) promotes tissue vascularization and angiogenesis in granulation tissue formation during development and repair. Bone Morphogenetic Proteins (BMPs) commit undifferentiated pluripotential cells to become bone- or cartilage-forming cells. 149

42 RESEARCH ABSTRACTS IMPORTANT GROWTH FACTORS INVOLVED IN INTRAORAL WOUND HEALING* Growth Factor Primary Effect Tissue Response Platelet Derived Growth Factor (PDGF) Chemotaxis Proliferation Angiogenesis Macrophage Activation Tranforming Growth Factors (TGF) Epidermal Growth Factor (EGF), including TGF-α Insulin-like Growth Factor (IGF) Chemotaxis Production of Extracellular Matrix Proliferation Proliferation Chemotaxis Production of Extracellular Matrix Proliferation Production of Extracellular Matrix Chemotaxis Cell Survival Collagen Production (Scarring) Down-Regulation of Other Cell Types but Fibroblasts Immunoregulation Epithelialization Tooth Eruption Stimulated DNA Synthesis Growth Promotion of Committed Cells Fibroblast Growth Factors (FGF) Proliferation Migration Formation of Extracellular Matrix Angiogenesis Epithelialization Vascular Endothelial Growth Factor (VEGF) Proliferation Angiogenesis Bone Morphogenetic Proteins (BMP) Differentiation Proliferation Production of Extracellular Matrix Bone Formation Root Cementum Formation Dentin Formation Periodontal Ligament Formation *Adapted from Storgård Jensen S 1 Shown below are examples of published in vitro and in vivo animal and human investigations examining the possible effects of low-level laser irradiation on various growth factors involved in wound healing. These and other researchers are building upon the foundation of understanding assembled by Endre Mester and other pioneers of photobiomodulation. As always, clinicians are advised to review the specific indications for use of their lasers and to review their operator manuals for guidance on operating parameters before attempting laser-assisted wound healing techniques on their patients. REFERENCE 1. Gottrup F, Storgård Jensen S, Andreasen JO. Wound healing subsequent to injury. Chapter 1 in: Andreasen JO, Andreasen FM, Andersson L, editors. Textbook and color atlas of traumatic injuries to the teeth. 4th ed. Oxford, UK: Blackwell Publishing Ltd., 2007:

43 RESEARCH ABSTRACTS EFFECTS OF LOW-LEVEL HE-NE LASER IRRADIATION ON THE GENE EXPRESSION OF IL-1, TNF-, IFN-Á, TGF-, bfgf, AND PDGF IN RAT S GINGIVA Sayed Mohammadreza Safavi, a Bahram Kazemi a ; Mostafa Esmaeli, b Alireza Fallah, b Alireza Modarresi, b Maziar Mir b a Shaheed Beheshti University of Medical Sciences, Tehran, Iran; b Basic Sciences Research Department, Center for Dental Research, Tehran, Iran Lasers Med Sci 2008;23(3): Biostimulatory effects of laser irradiation on cell proliferation and wound healing has been reported. However, little is known about the molecular basis of the mechanism. Interleukin 1 (IL-1 ), tumor necrotic factor-alpha (TNF- ), and interferon-á (IFN-Á) play an important role in inflammation, while platelet-derived growth factor (PDGF), transforming growth factor- (TGF- ) and blood-derived fibroblast growth factor (bfgf) are the most important growth factors of periodontal tissues. The aim of this study was to investigate the effect of low-level He-Ne laser on the gene expression of these mediators in rats gingiva and mucosal tissues. Twenty male Wistar rats were randomly assigned into four groups (A 24,A 48,B 24,B 48 ) in which A 24 and A 48 were cases and B 24, B 48 were controls. An incision was made on gingiva and mucosa of the labial surface of the rats mandibular incisors. Group A 24 was irradiated twice with 24 hours interval, while the inflamed tissues of group A 48 were irradiated three times with continuous He-Ne laser (632.8 nm) at a dose of 7.5 J/cm 2 for 300 s. An energy of 5.1 J was given to the 68 mm 2 irradiation zone. Rats were killed 30 min after the last irradiation of case and control groups, then excisional biopsy was performed. Gene expression of the cytokines was measured using reverse transcriptase-polymerase chain reaction (RT-PCR) technique. Results were analyzed with Kruskal-Wallis and Mann-Whitney U tests. The gene expression of IL-1 and IFN-Á was significantly inhibited in the test groups (P < 0.05), while the gene expression of PDGF and TGF- were significantly increased (P < 0.05). The case and control groups did not have a significant difference in the gene expression of TNF- and bfgf (P > 0.05). These findings suggest that low-level He-Ne laser irradiation decreases the amount of inflammation and accelerates the wound healing process by changing the expression of genes responsible for the production of inflammatory cytokines. Copyright 2007 Springer-Verlag London Limited LOW-INTENSITY LASER IRRADIATION STIMULATES BONE NODULE FORMATION VIA INSULIN-LIKE GROWTH FACTOR-I EXPRESSION IN RAT CALVARIAL CELLS Noriyoshi Shimizu, DDS, PhD a ; Kotoe Mayahara, DDS, PhD a ; Takeshi Kiyosaki, DDS a ; Akikuni Yamaguchi, DDS a ; Yasuhiro Ozawa, DDS, PhD b ; Yoshimitsu Abiko, DDS, PhD b Background and Objective: We previously reported that low-intensity laser irradiation stimulated bone nodule formation through enhanced cellular proliferation and differentiation. However, the mechanisms of irradiation are unclear. Thus, we attempted to determine the responsibility of insulin-like growth factor (IGF)-I for the action observed. Study Design/Materials and Methods: Osteoblast-like cells were isolated from fetal rat calvariae and cultured with rat recombinant (r) IGF-I, IGF-I-antibody (Ab), and/or the cells were irradiated once (3.75 J/cm 2 ) with a low-intensity Ga-Al-As laser (830 nm). The number and area of bone nodules a Nihon University School of Dentistry, Tokyo, Japan b Nihon University School of Dentistry at Matsudo, Matsudo, Japan Lasers Surg Med 2007;39(6): formed in the culture were analyzed, and IGF-I expression was also examined. Results: Treatment with rigf-i significantly stimulated the number and area of bone nodules. This stimulatory effect was quite similar to those by laser irradiation, and this stimulation was abrogated dose-dependently by treatment with IGF-I- Ab. Moreover, laser irradiation significantly increased IGF-I protein and gene expression. Conclusion: The stimulatory effect of bone nodule formation by lowintensity laser irradiation will be at least partly mediated by IGF-I expression. Copyright 2007 Wiley-Liss, Inc. 151

44 RESEARCH ABSTRACTS ACTIVATION OF LATENT TGF- 1 BY LOW-POWER LASER IN VITRO CORRELATES WITH INCREASED TGF- 1 LEVELS IN LASER-ENHANCED ORAL WOUND HEALING Praveen R. Arany, MDS a,b ; Ramakant S. Nayak, MDS b ; Seema Hallikerimath, MDS b ; Anil M. Limaye, PhD a ; Alka D. Kale, MDS b ; Paturu Kondaiah, PhD a a Indian Institute of Science, Bangalore, Karnataka, India b K.L.E. s Institute of Dental Sciences, Belgaum, Karnataka, India Wound Repair Regen 2007;15(6): The term Laser Photobiomodulation was coined to encompass the pleiotropic effects of low-power lasers on biological processes. The purpose of this study was to investigate whether transforming growth factor (TGF)- had a role in mediating the biological effects of low-power far-infrared laser irradiation. We assayed for in vitro activation using various biological forms of cellsecreted, recombinant, and serum latent TGF- using the p3tp reporter and enzyme-linked immunosorbent assays. We demonstrate here that low-power lasers are capable of activating latent TGF- 1 and - 3 in vitro and, further, that it is capable of priming these complexes, making them more amenable to physiological activation present in the healing milieu. Using an in vivo oral tooth extraction-healing model [in 30 human patients], we observed an increased TGF- 1, but not 3, expression by immunohistochemistry immediately following laser irradiation while TGF- 3 expression was increased after 14 days, concomitant with an increased inflammatory infiltrate. All comparisons were performed between laser-irradiated wounds and nonirradiated wounds in each subject essentially using them as their own control (paired T-test p < 0.05). Low-power laser irradiation is capable of activating the latent TGF- 1 complex in vitro and its expression pattern in vivo suggests that TGF- play a central role in mediating the accelerated healing response. Copyright 2007 The Wound Healing Society LOW-LEVEL LASER THERAPY INCREASES TRANSFORMING GROWTH FACTOR- 2 EXPRESSION AND INDUCES APOPTOSIS OF EPITHELIAL CELLS DUR I NG THE TISSUE REPAIR PROCESS Adeir Moreira Rocha Júnior a ; Beatriz Juliúo Vieira b ; Luis Carlos Ferreira de Andrade c ; Background Data: Low-level laser therapy (LLLT) has been reported to modulate the healing of wounds by inducing an increase in mitotic activity, fibroblast number, synthesis of collagen, and neovascularization. Objective: In the present study we evaluated the effect of LLLT on expression of TGF- 2, an immunosuppressive cytokine, at the site of tissue repair, using an experimental rat model to study cutaneous wound healing. In addition, we also investigated the presence of apoptotic cells in epithelial and connective tissue. Materials and Methods: Thirty male Wistar rats were divided into two groups: group 1, which was subjected to surgical skin wounds only (n = 15), and group 2, which was subjected to surgical skin wounds followed by LLLT (n = 15). In group 2, the LLLT was given with these parameters: 15 mw of power, a dose of 3.8 J/cm 2, Fernando Monteiro Aarestrup d a Universidade Federal de Juiz de Fora-MG, Brazil; b Universidade Federal Fluminense, Universidade Federal de Juiz de Fora-MG, Brazil; c Universidade Federal de São Paulo, Brazil; d Universidade Federal Fluminense, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil Photomed Laser Surg 2009;27(2): for 15 sec for three applications. At 10 d post-surgery and laser application the animals were sacrificed with an overdose of anesthetic and tissue samples from the wounds were submitted to immunohistochemistry and in-situ detection of apoptosis. Results: Most of the inflammatory cells and fibroblasts were TGF- 2 -positive, and many apoptotic epithelial cells and fibroblasts were seen in the tissue samples from the LLLT-treated animals. However, a few apoptotic epithelial cells and fibroblasts were also seen in the samples obtained from control animals. Conclusion: Our results indicate that LLLT may be an important inducer of apoptosis during the process of tissue repair. In addition, we demonstrated that LLLT has an immunomodulatory effect on TGF- 2 expression at sites of wound healing. Copyright 2009 Mary Ann Liebert, Inc. 152

45 RESEARCH ABSTRACTS LOW-LEVEL LASER THERAPY ACCELERATES COLLATERAL CIRCULATION AND ENHANCES MICROCIRCULATION F.R. Mohammed Ihsan, PhD AL-Kindy College of Medicine, University of Baghdad, Iraq Photomed Laser Surg 2005;23(3): Objective: To evaluate the efficacy of low-level laser therapy (LLLT) on collateral circulation and microcirculation if a blood vessel is occluded. Background Data: Investigators have attempted prostaglandin and ultrasound therapy to promote improvements in the vascular bed of deprived tissue after an injury, which may lead to occlusion of the blood vessels. Materials and Methods: Thirty-four adult rabbits were used in this study, two of them considered 0-h reading group, while the rest were divided into two equal groups, with 16 rabbits each: control and those treated with LLLT. Each rabbit underwent two surgical operations; the medial aspect of each thigh was slit, the skin incised and the femoral artery exposed and ligated. The site of the operation in the treated group was irradiated directly following the operation and for 3 d after, one session daily for 10 min/session. The laser system used was a gallium-aluminum-arsenide (Ga-Al-As) diode laser with a wavelength of 904 nm and power of 10 mw. Blood samples collected from the femoral artery above the site of the ligation were sent for examination with high-performance liquid chromatography (HPLC) to determine the levels of adenosine, growth hormone (GH) and fibroblast growth factor (FGF). Tissue specimens collected from the site of the operation, consisting of the artery and its surrounding muscle fibers, were sent for histopathological examination to determine the fiber/capillary (F/C) ratio and capillary diameter. Blood samples and tissue specimens were collected at 4, 8, 12, 16, 20, 24, 48, and 72 h postoperatively from the animals of both groups, control and treated. Results: Rapid increases in the level of adenosine, GH, and FGF occurred. The F/C ratio and capillary diameter peaked at h; their levels declined gradually, reaching normal values 72 h after irradiation in the treated group. Numerous collateral blood vessels proliferated the area, with marked increases in the diameters of the original blood vessels. Conclusions: The results indicated that LLLT accelerated collateral circulation and enhanced microcirculation and seemed to be unique in the normalization of the functional features of the injured area, which could lead to occlusion of the regional blood vessels. Copyright 2005 Mary Ann Liebert, Inc. SUPERPULSED LASER IRRADIATION INCREASES OSTEOBLAST ACTIVITY VIA MODULATION OF BONE MORPHOGENETIC FACTORS Silvia Saracino, BSc; Marco Mazzati, DDS; Germana Martinasso, PhD; Renato Pol, DMD; Rosa A. Canuto, MD; Giuliana Muzio, PhD Background and Objective: Laser therapy is a new approach applicable in different medical fields when bone loss occurs, including orthopedics and dentistry. It has also been used to induce soft-tissue healing, for pain relief, bone, and nerve regeneration. With regard to bone synthesis, laser exposure has been shown to increase osteoblast activity and decrease osteoclast number, by inducing alkaline phosphatase (ALP), osteopontin, and bone sialoprotein expression. Studies have investigated the effects of continuous or pulsed laser irradiation, but no data are yet available on the properties of superpulsed laser irradiation. This study thus aimed to investigate the effect of superpulsed laser irradiation on osteogenic activity of human osteoblast-like cells, paying particular attention to investigating the molecular mechanisms underlying the effects of this type of laser radiation. Study Design/Materials and Methods: Human osteoblastlike MG-63 cells were exposed to 3, 7, or 10 exposures to superpulsed laser irradiation (pulse width 200 nanoseconds, minimum peak power 33 W, average out power 200 University of Turin, Turin, Italy Lasers Surg Med 2009;41(4): mw, frequency 30 khz, total energy 60 J, exposure time 5 minutes), with an administered dose of 6.7 J/cm 2. The following parameters were evaluated: cell growth and viability (light microscopy, lactate dehydrogenase release), calcium deposits (Alizarin Red S staining), expression of bone morphogenetic factors (real-time PCR). Results: Superpulsed laser irradiation decreases cell growth, induces expression of TGF- 2, BMP-4, and BMP-7, type I collagen, ALP, and osteocalcin, and increases the size and the number of calcium deposits. The stimulatory effect is maximum on day 10, that is, after seven applications. Conclusions: Reported results show that superpulsed laser irradiation, like the continuous and pulsed counterparts, possesses osteogenic properties, inducing the expression of molecules known to be important mediators of bone formation and, as a consequence, increasing calcium deposits in human MG- 63 cells. Moreover, the data suggest a new potential role for PPARÁ as a regulator of osteoblast proliferation. Copyright 2009 Wiley-Liss, Inc. 153

46 RESEARCH ABSTRACTS IN VIVO EFFECTS ON THE EXPRESSION OF VASCULAR ENDOTHELIAL GROWTH FACTOR-A 165 MESSENGER RIBONUCLEIC ACID OF AN INFRARED DIODE LASER ASSOCIATED OR NOT WITH A VISIBLE RED DIODE LASER Thiago C. Silva, DDS, MSc a ; Thaís M. Oliveira, DDS, MSc, PhD a ; Vivien T. Sakai, DDS, MS, PhD a ; Thiago J. Dionísio a ; Carlos F. Santos, DDS, MSc, PhD a ; Vanderlei S. Bagnato, DDS, MSc, PhD b ; Maria Aparecida A.M. Machado, DDS, MSc, PhD a a Bauru School of Dentistry, University of São Paulo, Bauru, Brazil b Institute of Physics of São Carlos, University of São Paulo, Bauru, Brazil Photomed Laser Surg. Epub 2009 Sep 22. DOI =pho Objective: This study investigated and correlated the kinetic expression of vascular endothelial growth factor (VEGF)-A 165 messenger ribonucleic acid (mrna) with the associated use or not of an infrared laser and a visible red laser during the wound healing in rats. Background Data: There is a lack of scientific evidence demonstrating the influence of low-level laser therapy (LLLT) on the expression of VEGF mrna in vivo. Materials and Methods: Forty-five Wistar rats were randomly allocated to one of three groups: I (n = 5, nonoperated animals), II (n = 25, operated animals), and III (n = 25, animals operated and subjected to laser irradiation). A surgical wound was performed using a scalpel in the right side of the tongue of operated animals. In group III, two sessions of laser irradiation were performed, one right after the surgical procedure (infrared laser, 780 nm, 70 mw, 35 J/cm 2 ) and the other 48 h later (visible red laser, 660 nm, 40 mw, 5 J/cm 2 ). Five animals each were sacrificed 1, 3, 5, and 7 days postoperatively in groups II and III, and samples of tongue tissue were obtained. The animals of group I were sacrificed on day 7. Total RNA was extracted using guanidine-isothiocyanate-phenol-chloroform method. The results of horizontal electrophoresis after reverse transcription polymerase chain reaction permitted the ratio of VEGF-A 165 mrna and glyceraldehyde 3-phosphate dehydrogenase mrna expression for groups I, II, and III to be assessed (twoway analysis of variance and Tukey test, p < 0.05). Results: The expression of VEGF-A 165 mrna in group II ( / ) was statistically greater than that observed in groups I (0.523 ± 0.164) and III (0.504 ± 0.069) in the first day after surgery (p < 0.05). Significant differences between the groups were not observed in other time periods. Conclusion: LLLT influenced the expression of VEGF-A 165 mrna during wound healing after a surgical procedure on the tongue of Wistar rats. Copyright 2009 Mary Ann Liebert, Inc. 154

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