Incorporating Magnification Into Your Dental Practice

Transcription

1 Incorporating Magnification Into Your Dental Practice 2nd Edition By Glenn A. van As, DMD Release date: FILL IN, 2016 Expiration date: FILL IN, clock hours will be awarded upon successful completion of this course.

2 P.O. Box 1930 Brockton, MA ABOUT THE AUTHOR Glenn A. van As, DMD, graduated in 1987 from the University of British Columbia (UBC), Vancouver, Canada. In addition to being in full-time private practice, he served as an assistant clinical professor at UBC from 1989 to His areas of interest and expertise involve the use of the dental operating microscope for all of his clinical dentistry and the use of multiple wavelengths of hard and soft tissue lasers for many procedures in his private general practice. He has lectured, provided hands-on workshops, and published internationally on the clinical value of multiple wavelengths of lasers and the high magnifications attainable with the dental operating microscope. Dr. van As has obtained standard proficiency (in argon wavelength) and advanced proficiency (in erbium wavelength) from the Academy of Laser Dentistry. In 2006, he received the Leon Goldman Award for clinical excellence. He is a founding member and past president of the Academy of Microscope Enhanced Dentistry and actively contributes to many online forums that address topics related to the use of lasers and microscopes in general practice. He is well known for his collection of digital microphotographs and videography captured through the microscope at magnifications of 2.5 to 24. Dr. van As has lectured and published extensively and is in full-time private practice. Glenn A. van As has disclosed that he has no significant financial or other conflicts of interest pertaining to this course book. ABOUT THE PEER REVIEWER Donato Napoletano, DMD, is a graduate of Boston University School of Dental Medicine and has been in a multispecialty private practice in Middletown, New York, since Dr. Napoletano has incorporated diverse technologies into his practice, including digital radiography, dental computer-aided design and manufacturing (CAD/CAM) systems, surgical microscopes, and three laser wavelengths. The author of numerous articles on new dental technologies, Dr. Napoletano also serves as a consultant, helping dentists evaluate, select, and integrate these new technologies into their practices. Donato Napoletano has disclosed that he has no significant financial or other conflicts of interest pertaining to this course book. Dental Planner: Karen Hallisey, DMD The planner has disclosed that she has no significant financial or other conflicts of interest pertaining to this course book. Copy Editor: Jeanne Hansen Proofreader: Ann G. Boyer Western Schools courses are designed to provide healthcare professionals with the educational information they need to enhance their career development as well as to work collaboratively on improving patient care. The information provided within these course materials is the result of research and consultation with prominent healthcare authorities and is, to the best of our knowledge, current and accurate at the time of printing. However, course materials are provided with the understanding that Western Schools is not engaged in offering legal, medical, or other professional advice. Western Schools courses and course materials are not meant to act as a substitute for seeking professional advice or conducting individual research. When the information provided in course materials is applied to individual cases, all recommendations must be considered in light of each case s unique circumstances. Western Schools course materials are intended solely for your use and not for the purpose of providing advice or recommendations to third parties. Western Schools absolves itself of any responsibility for adverse consequences resulting from the failure to seek medical, or other professional advice. Western Schools further absolves itself of any responsibility for updating or revising any programs or publications presented, published, distributed, or sponsored by Western Schools unless otherwise agreed to as part of an individual purchase contract. Products (including brand names) mentioned or pictured in Western Schools courses are not endorsed by Western Schools, any of its accrediting organizations, or any state licensing board. COPYRIGHT 2018 S.C. Publishing. All Rights Reserved. No part(s) of this material may be reprinted, reproduced, transmitted, stored in a retrieval system, or otherwise utilized, in any form or by any means electronic or mechanical, including photocopying or recording, now existing or hereinafter invented, nor may any part of this course be used for teaching without written permission from the publisher. FP0218WS ii

3 COURSE INSTRUCTIONS IMPORTANT: Read these instructions BEFORE proceeding! HOW TO EARN CONTINUING EDUCATION CREDIT To successfully complete this course you must: 1) Read the entire course 2) Pass the final exam with a score of 75% or higher* 3) Complete the course evaluation *You have three attempts to pass the exam. If you take the exam online, and fail to receive a passing grade, select Retake Exam. If you submit the exam by mail or fax and you fail to receive a passing grade, you will be notified by mail and receive an additional answer sheet. Final exams must be received at Western Schools before the Complete By date located at the top of the FasTrax answer sheet enclosed with your course. Note: The Complete By date is either 1 year from the date of purchase, or the expiration date assigned to the course, whichever date comes first. HOW TO SUBMIT THE FINAL EXAM AND COURSE EVALUATION ONLINE: BEST OPTION! For instant grading, regardless of course format purchased, submit your exam online at Benefits of submitting exam answers online: Save time and postage Access grade results instantly and retake the exam immediately, if needed Identify and review questions answered incorrectly Access certificate of completion instantly Note: If you have not yet registered on Western Schools website, you will need to register and then call customer service at to request your courses be made available to you online. Mail or Fax: To submit your exam and evaluation answers by mail or fax, fill out the FasTrax answer sheet, which is preprinted with your name, address, and course title. If you are completing more than one course, be sure to record your answers on the correct corresponding answer sheet. Complete the FasTrax Answer Sheet using blue or black ink only. If you make an error use correction fluid. If the exam has fewer than 100 questions, leave any remaining answer circles blank. Respond to the evaluation questions under the heading Evaluation, found on the right-hand side of the FasTrax answer sheet. See the FasTrax Exam Grading & Certificate Issue Options enclosed with your course order for further instructions. CHANGE OF ADDRESS? Contact our customer service department at , or customerservice@westernschools.com, if your postal or address changes prior to completing this course. WESTERN SCHOOLS GUARANTEES YOUR SATISFACTION If any continuing education course fails to meet your expectations, or if you are not satisfied for any reason, you may return the course materials for an exchange or a refund (excluding shipping and handling) within 30 days, provided that you have not already received continuing education credit for the course. Software, video, and audio courses must be returned unopened. Textbooks must not be written in or marked up in any other way. Thank you for using Western Schools to fulfill your continuing education needs! WESTERN SCHOOLS P.O. Box 1930, Brockton, MA iii

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5 WESTERN SCHOOLS course evaluation INCORPORATING MAGNIFICATION INTO YOUR DENTAL PRACTICE INSTRUCTIONS: Using the scale below, please respond to the following evaluation statements. All responses should be recorded in the lower right-hand corner of the FasTrax answer sheet, in the section marked Evaluation. Be sure to fill in each corresponding answer circle completely using blue or black ink. Leave any remaining answer circles blank. A B C D Agree Agree Disagree Disagree Strongly Somewhat Somewhat Strongly OBJECTIVES: After completing this course, I am able to: 1. Discuss the evolution of the use of magnification in the field of dentistry. 2. Describe the resolution of the naked eye and how magnification can improve visual acuity. 3. Identify the magnification alternatives available in dental practice. 4. Discuss the concept of the magnification continuum and its impact on dental clinicians. 5. Explain the advantages of using surgical telescopic loupes in dentistry. 6. Explain the advantages of using a dental operating microscope in dentistry. 7. Discuss the challenges of incorporating magnification into the daily practice of dentistry. COURSE CONTENT 8. The course content was presented in a well-organized and clearly written manner. 9. The course content was presented in a fair, unbiased and balanced manner. 10. The course content presented current developments in the field. 11. The course was relevant to my professional practice or interests. 12. The final examination was at an appropriate level for the content of the course. 13. The course expanded my knowledge and enhanced my skills related to the subject matter. 14. I intend to apply the knowledge and skills I ve learned to my practice. A. Yes B. Unsure C. No D. Not Applicable CUSTOMER SERVICE The following section addresses your experience in interacting with Western Schools. Use the scale below to respond to the statements in this section. A. Yes B. No C. Not Applicable 15. Western Schools staff was responsive to my request for disability accommodations. 16. The Western Schools website was informative and easy to navigate. 17. The process of ordering was easy and efficient. 18. Western Schools staff was knowledgeable and helpful in addressing my questions or problems. v continued on next page

6 vi Course Evaluation Incorporating Magnification Into Your Dental Practice ATTESTATION 19. I certify that I have read the course materials and personally completed the final examination based on the material presented. Mark A for Agree and B for Disagree. COURSE RATING 20. My overall rating for this course is A. Poor B. Below Average C. Average D. Good E. Excellent COURSE SELECTION 21. What is your preferred course length for self-study continuing education? A. 1-2 hours B. 3-5 hours C. 6-9 hours D. 10 or more hours 22. What led you to Western Schools to purchase this particular course? A. Conducted an online search B. Redirected from the ADI or GSC website C. Received a Western Schools catalog in the mail D. Received a Western Schools E. Heard about Western Schools from a friend/colleague You may be contacted within 3 to 6 months of completing this course to participate in a brief survey to evaluate the impact of this course on your clinical practice and patient/client outcomes. Note: To provide additional feedback regarding this course and Western Schools services, or to suggest new course topics, use the space provided on the Important Information form found on the back of the FasTrax instruction sheet included with your course.

7 CONTENTS Course Evaluation...v Figures and Tables...ix Introduction...xi Course Objectives...xi Incorporating Magnification Into Your Dental Practice...1 The Evolution of the Use of Magnification in the Field of Dentistry...1 Resolution of the Naked Eye and the Impact of Magnification...2 Magnification Alternatives in Dental Practice...3 Magnification Continuum...5 Advantages of Using Surgical Telescopic Loupes In Dentistry...9 Advantages of Using a DOM...10 Challenges of Incorporating Magnification Into Daily Practice...15 Summary...15 Exam Questions...17 References...21 vii

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9 FIGURES AND TABLES Figure 1: Example of a 2.5 Flip-Up Loupe...2 Figure 2: Example of a 4.5 Through-the-Lens (TTL) Loupe With Headlamp...2 Table 1: Resolution of the Human Eye as Improved With Magnification...2 Table 2: Nonlinear Relationship Between Increasing Magnification and Amount of Visual Information That Passes to the Retina...3 Figure 3: Relationship Between Magnification and Amount of Visual Information Seen by the Retina...3 Figure 4: The 2001 Magnification Continuum...5 Figure 5: The 2013 Magnification Continuum...5 Figure 6: Vision Through Loupes Versus Microscope...7 Figure 7: Loupe Progression From 2.5 Flip-Up, to 3.5 Flip-Up, to 4.5 Extended Field of View TTL...7 Figure 8a: Microscope With Six Magnification Levels (2.1, 3.2, 5, 8, 13, 19.2 )...8 Figure 8b: DOM With Three-Chip Digital Video Camera (Left) and Digital Single-Lens Reflex Camera (Right)...8 Figure 9a: Microscope-Centered Operatory...8 Figure 9b: DOM and Microsurgeon s Chair Used for Restorative Dentistry in Operatory...8 Figure 10: Magnification Continuum From Naked Eye to DOM...9 Figure 11: Dental Hygienist With Improved Posture Using 2.5 TTL Loupes With Headlamp...10 Figure 12: Key Ergonomic Factors to Consider With Surgical Loupes...10 Figure 13a: 2.1 Magnification...11 Figure 13b: 8 Magnification...11 Figure 13c: 19 Magnification...11 Figure 14: MB1 and MB2 Canal (8 Magnification)...11 Figure 15: Pulp Chamber of a Lower Molar...11 Figure 16: Early Occlusal Caries (13 Magnification)...12 Figure 17: Cracked Tooth (13 Magnification)...12 Figure 18: Veneer Preps (5 Magnification)...12 Figure 19: Evaluating Impressions (13 Magnification)...12 Figure 20: Crown Prep (13 Magnification)...12 Figure 21: Veneer Cement Removal (19 Magnification)...12 Figure 22: Ergonomic Benefits of Using a Microscope...13 Figure 23: Accessibility Benefits of Using a Microscope...13 Figure 24: Benefits of Using Video With a Microscope...13 Figure 25: Projection of 3-D Images...14 ix

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11 INTRODUCTION COURSE OBJECTIVES After completing this course, the learner will be able to: 1. Discuss the evolution of the use of magnification in the field of dentistry. 2. Describe the resolution of the naked eye and how magnification can improve visual acuity. 3. Identify the magnification alternatives available in dental practice. 4. Discuss the concept of the magnification continuum and its impact on dental clinicians. 5. Explain the advantages of using surgical telescopic loupes in dentistry. 6. Explain the advantages of using a dental operating microscope in dentistry. 7. Discuss the challenges of incorporating magnification into the daily practice of dentistry. Dentistry has encountered a tremendous surge in technology over the past 3 decades in nearly all areas, including armamentarium, materials, and techniques. Patients now wish to maintain their own dentition for their lifetime, and they are keenly aware of the improvement that cosmetic dentistry can make to their appearance. Although technological advancements have given dentists a new opportunity to provide clinically excellent results, dentists must observe microscopic attention to detail in the use of both materials and techniques. Clinicians must now focus on providing dentistry that is not only functional, but also esthetically exceptional, with minimal intervention or, in some cases, no intervention at all. These factors have created a challenge for many clinicians as patients increasingly expect and demand long-lasting invisible white restorations. This basic-level course designed for dentists, dental hygienists, and dental assistants explains the basics of incorporating magnification into dental practice. The course describes the evolution of the use of magnification in the field of dentistry, along with the magnification alternatives currently available, including surgical telescopic loupes and the dental operating microscope. The concept of the magnification continuum is also explained, and the challenges of incorporating magnification into the daily practice of dentistry are identified. xi

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13 INCORPORATING MAGNIFICATION INTO YOUR DENTAL PRACTICE THE EVOLUTION OF THE USE OF MAGNIFICATION IN THE FIELD OF DENTISTRY The increasing demand of patients for esthetic, conservative, and durable restorations requires clinicians to visualize the operating field in greater detail. The field of medicine has long advocated the use of magnification to aid delicate procedures. Disciplines such as otolaryngology, neurology, and (more recently) acute care have embraced magnification for surgery and delicate procedures such as reanastomoses of severed appendages. Our medical colleagues have relied on enhanced visual acuity to improve treatment outcomes for many years. The dental profession has been slower to adopt magnification in clinical practice. At one time, magnification was thought to be reserved for mature practitioners whose eyesight was failing. The perception was that, after age 45, clinicians needed to use magnifiers because of presbyopia age-related weakening of the ciliary muscles in the eye that causes an inability to focus sharply on close objects. Today magnification is understood to improve ergonomics and ultimately treatment outcomes, and it is interesting to note that many dental schools and dental hygiene schools are requiring students to purchase magnification as part of their armamentarium. Further, magnification has proven to be 1 a useful tool during the teaching process itself, and although currently not all faculty members embrace the value of magnification, a growing number of dental schools and dental hygiene programs have acknowledged its importance to dental education. The usage of surgical telescopes (loupes) has increased dramatically, growing from a rarity to the norm in general dental practice. In 1999 one survey found that 52% of endodontists had access to and used an operating microscope; most often clinicians were using the microscope for difficult treatments in which high levels of magnification were required, such as separated instruments, root-end preparations, and root-end fillings (Mines, Loushine, West, Liewehr, & Zadinsky, 1999). A similar survey in 2008 found that 90% of endodontists in the United States had access to and used an operating microscope in their practice for purposes similar to those found in the 1999 study, but that a greater number were using an operating microscope for locating canal orifices (Kersten, Mines, & Sweet, 2008). In 2012 the American Association of Endodontists produced a position paper urging members to seek training in the use of magnification (American Association of Endodontists, 2012). There is a growing interest in all levels of magnification, and this course will discuss reasons for incorporating magnification into practice and the alternatives, benefits, and challenges of magnification.

14 2 Incorporating Magnification Into Your Dental Practice RESOLUTION OF THE NAKED EYE AND THE IMPACT OF MAGNIFICATION In a landmark 1998 article, Dr. Gary B. Carr cited research from the medical literature showing that the human eye, when unaided by magnification, has the ability to resolve or distinguish two distinct lines or objects that are separated by a minimum distance of 200 µm (microns), or 0.2 mm (Carr, 1998). If the lines are closer together than 0.2 mm, the eye will see them as a single line (Carr & Murgel, 2010). Magnification improves the ability of the human eye to resolve objects and allows the clinician to see greater detail than is possible with the naked eye alone (Urlic, Verzak, & Vranic, 2016). For example, 2.5 magnifiers, such as telescopic loupes (Figure 1), improve the resolution of the human eye to 80 µm, whereas 4.5 telescopic loupes (Figure 2) improve the resolution of the human eye to 44 µm or mm (also see Table 1). Baldissara and others showed that a skilled, trained clinician with a sharp new explorer can detect marginal gaps in the range of 35 to 50 µm (Baldissara, Baldissara, & Scotti, 1998). It is therefore possible to conclude that at levels FIGURE 1: EXAMPLE OF A 2.5 FLIP-UP LOUPE FIGURE 2: EXAMPLE OF A 4.5 THROUGH-THE-LENS (TTL) LOUPE WITH HEADLAMP above 4 to 6 magnification, the dependence on tactile cues may be replaced with a greater reliance on visual cues. It is interesting to note that a dental operating microscope (DOM) at 20 power will provide a resolution of 10 µm. (For comparative purposes, a human hair is approximately 50 µm in width; van As, 2013a). Some clinicians are surprised by how much more they see when they increase the amount of magnification they are using. The amount of visual information that is provided to the clinician is the area of the surgical site (X axis Y axis) and is indicative of the power of increasingly higher levels of magnification. Table 2 and Figure 3 show the impact of higher levels of magnifiers on the amount of visual information that is provided. TABLE 1: RESOLUTION OF THE HUMAN EYE AS IMPROVED WITH MAGNIFICATION Magnification Unaided vision Resolution of the Eye 200 µm (0.2 mm) 2 loupe 100 µm (0.1 mm) 4 loupe 50 µm (0.05 mm) 8 microscope 25 µm (0.025 mm) 12 microscope µm ( mm) 20 microscope 10 µm (0.01 mm)

15 Incorporating Magnification Into Your Dental Practice 3 TABLE 2: NONLINEAR RELATIONSHIP BETWEEN INCREASING MAGNIFICATION AND AMOUNT OF VISUAL INFORMATION THAT PASSES TO THE RETINA Magnification Visual Information (X Y) Unaided vision 1 2 loupe 4 unaided vision 4 loupe 16 unaided vision 8 microscope 64 unaided vision 16 times 2 loupe 12 microscope 144 unaided vision 24 times 2 loupe 20 microscope 400 unaided vision 100 times 2 loupe The incremental magnification jump from 2 to 4 magnifiers will not just double what the clinician can see; it will provide a fourfold increase in the amount of visual information. Correspondingly, when an operating microscope is employed at 12 magnification, the amount of visual information is 24 times what is seen with a 2 loupe. As clinicians begin to understand how seeing better may ultimately mean better treatment outcomes, they will consider the routine use of magnification in daily practice to be a necessity rather than a luxury. FIGURE 3: RELATIONSHIP BETWEEN MAGNIFICATION AND AMOUNT OF VISUAL INFORMATION SEEN BY THE RETINA No Mag 2 Mag 4 Mag 8 Mag 12 Mag 16 Mag Magnification (X axis) vs Visual Information (Y axis) MAGNIFICATION ALTERNATIVES IN DENTAL PRACTICE There are three basic magnification systems available in dentistry for surgical telescopes. These systems include single-lens (Amsted) loupes, Galilean loupes, and prismatic (Keplerian) loupes (Perrin, Eichenberger, Neuhaus, & Lussi, 2016): Single-lens (Amsted) loupes are the simplest form of magnification and are low-powered, clip-on magnifying lenses that attach to a pair of glasses or a headband. They are less expensive than other types of loupes and have limited magnification (up to about 3 ) and limited depth and diameter of field of vision. Galilean loupes provide 2 to 2.5 magnification. They use two or more lenses to focus the image. These systems are more expensive than single-lens loupes, and although the level of magnification is limited, the depth and diameter of the field of view, and the resolution of the image, are improved. Prismatic (Keplerian) loupes have multiple lenses (approximately five lenses and two prisms) to focus the image and give greater clarity. Among the disadvantages of these

16 4 Incorporating Magnification Into Your Dental Practice loupes are that they are more expensive to fabricate, and the lenses are larger and heavier so they produce a smaller depth of field as the magnification increases. When choosing a first set of loupes, clinicians need to consider a number of factors. Whereas clinicians should look at the magnification of the system and choose a set of loupes that will offer the greatest chance of initial adaptation (2 to 3 is the most-often suggested initial magnification), they must also look at the field width, depth of field, and whether they want to flip up the loupes for an unmagnified assessment of the field of view. Typically, flip-up loupes are bulkier and heavier than through-the-lens (TTL) loupes and can easily go out of adjustment, which can affect not only the view (double image) but also the clinician s posture. The ability of TTL loupes to be mounted directly into a prescription lens must be weighed against the need for adjustments when the prescription changes. Furthermore, TTL loupes can be mounted only at an angle (called the declination angle, or the angle at which the practitioner s eyes will be inclined downward) from horizontal up to about 45. The heavier the prismatic (Keplerian) loupes, the greater the tendency for the loupes to ride down the bridge of the nose, necessitating a strap that fits tightly around the back of the head to hold the loupes in place. Clinicians should focus on the proper working distance because many loupe systems can vary the focal distance. The working distance can be set to accommodate the preferences of operators, from a near focal distance for those who like to lean closer to the operating field, to a farther distance for those who like to sit upright and away from the surgical site. Under ideal circumstances, the latter is better from an ergonomic standpoint because the operator will experience less fatigue in the lower back and upper spine (including the neck and shoulders) when sitting in a more upright position. It is nearly impossible to achieve straightforward vision when using a set of loupes, whereas straightforward vision can be obtained with an operating microscope. If a clinician suffers from severe neck and back pain, an operating microscope may lessen the discomfort. Although neither single lens, Galilean, nor prismatic loupes allow perfect posture, welldesigned loupes can enable a working position of 25 forward (Valachi, 2009; van As, 2013b). The three most important considerations when choosing a set of loupes are the declination angle, the working distance, and the frame size. It is important to choose loupes with a good declination angle that will allow for as minimal a forward head position as possible because the more forward the loupes push the head, the more likely there will be strain on the neck muscles and discs. If the chosen working distance to the surgical site is too short, the operator will likely be forced either to hunch or to use excessive neck flexion to obtain a sharp image of the operating field (Valachi, 2006; van As, 2013b). It is important to realize that the working distance is related to the operator s height and is measured from the corner of the operator s eye to the working surface. The working distance can vary from 14 inches to more than 20 inches (36 cm to 51 cm) and needs to be tailored to the operator. Finally, the larger the glass frames, the better; larger frames allow the glasses to sit lower on the cheek and provide a better angle because TTL telescopes can be placed at a steeper declination angle at the bottom of the frames. As the level of magnification increases, the need for accessory illumination also increases. Many powerful light-emitting diode (LED) lights

17 Incorporating Magnification Into Your Dental Practice 5 offer tremendous illumination with reduced weight and extended battery life. The range in cost for loupes is typically between $700 and $2,200, depending on the manufacturer, magnification level, and type. A properly adjusted set of loupes, with appropriate declination angle, working distance, and frame size, can significantly reduce the risk of debilitating occupationally induced neck and back discomfort. MAGNIFICATION CONTINUUM The term magnification continuum was coined in 2001 to quantify the growing number of clinicians who were using magnification routinely in their dental practice (van As, 2001). At that time, many clinicians were just beginning their journey into enhanced visual acuity, while others had been using loupes for many years. In fact, it was not uncommon for dentists to have several different sets of magnifiers, ranging from low-level 2 to 2.5 loupes, to 6 loupes with a headlamp. Among experienced clinicians, there were waves of progression toward higher and higher levels of magnification. Appreciating the value of increased levels of expertise afforded by greater magnification, clinicians often looked to add new magnification systems to their armamentarium. In addition, some clinicians were opting to use DOMs that had multiple levels of magnification (2 to 20 ). These clin icians often worked in disciplines such as endodontics or cosmetic dentistry, in which magnification and illumination could help either with the discovery of pulpal anatomy or, in the case of cosmetic dentistry, enhance the final treatment aesthetics with detailed preparation (Figure 4). FIGURE 4: THE 2001 MAGNIFICATION CONTINUUM The Magnification Continuum M AG N IF I C AT I O N Amsted Loupes 2X Loupes 4X Loupes with headlamp TIME IN YEARS 5-8X Loupes with headlamp Dental Operating Microscope The original concept of the magnification continuum was further revised in 2013 to include two to three phases of magnification progression (Figure 5). Many dentistry and dental hygiene students are now introduced to the entry-level magnification of 2 to 2.5 during their education. This level of magnification is also a suggested starting point for more experienced clinicians looking for a solution to presbyopia, improved clinical results, or alleviation of neck and back pain. During this initial phase, the clinician will encounter a learning curve (Figure 5, point A) that often lasts from 1 week to 1 month. During this period of time, the clinician will FIGURE 5: THE 2013 MAGNIFICATION CONTINUUM Magnification Entry Level Magnification A. B. C. Medium Level Magnification D. Time E. F. High Level Magnification G. H. I.

18 6 Incorporating Magnification Into Your Dental Practice use the loupes for endodontics, cosmetics, difficult extractions of root tips, crown preparations, or other procedures and may also provide treatment without them. After one or two more periods of sustained use with shorter learning curves (Figure 5, point B), the clinician will use the loupes full-time for most procedures and at times question how he or she ever performed dentistry without them. With time and regular use, clinicians may eventually seek out higher powers of magnification (Figure 5, point C) and acquire their second, and perhaps eventually third, set of loupes. Initially, some practitioners may envision using the new medium-powered loupes (e.g., 3.5 magnification) only for endodontics or for difficult-to-visualize procedures (Figure 5, point D), and they may then move between the low and medium powers as the procedure dictates. With time, the dentist may then reach a period during which he or she is seldom using the lower power and using only the more recent purchase (Figure 5, point E). At times, clinicians will choose another higher magnification and incorporate a headlamp (often needed above 3.5 magnification), and now will have two or three different sets of loupes with a headlamp (Figure 5, point F). If the clinician enjoys endodontics, wants multiple powers of magnification without changing loupes, wants coaxial shadow-free illumination, and wants to easily document procedures, he or she might opt for a DOM or heads-up display system, which offers the ultimate in higher magnification levels. With this type of system, the clinician must learn to rely on indirect vision (intraoral mirrors) in both arches to optimize the view. Also, the clinician must learn to reposition the patient or the patient s head, rather than repositioning himor herself while the patient remains stationary (Figure 5, point G). Depending on the clinician, this learning period can take anywhere from 1 month to 1 year, but eventually the operator will learn to use all magnifications of the system from low to high power. After several phases of using only the lower powers of the microscope (Figure 5, point H), the clinician will, with time, learn to operate throughout the ranges of magnification and be able to comfortably work at most of the available magnifications as dictated by the procedure, the patient s needs, and the challenges that these considerations create for the clinician (Figure 5, point I). There is always a price to be paid for the increased visual detail provided by higher levels of magnification. Although the amount of visual information continues to increase, the clinical value of this information is maximal at around 20 magnification. The clinical depth of field and the difficulty of finite motor movements that are necessary to work at 20 magnification make this the approximate upper level of clinically valuable magnification. The stabilization of gross motor joints (elbows and shoulders) through the use of a microsurgeon s chair allows for improved control of micromotor muscles and joints (fingers and wrists). Earlier in the evolution of magnification in dental practice, Tibbetts and Shanelec (1998) demonstrated that, in working with high levels of magnification (20 power), clinicians could learn how to shrink their movements from 1,000 to 2,000 µm (1 to 2 mm) increments to as little as 10 to 20 µm (10 to 20/1,000th mm) increments at a time. It is useful, then, to appreciate that the limitation to precision treatments is not in the hands, but in the eyes. It is interesting to note that even though the magnification continuum for many clinicians consists of three phases, some clinicians never see the need to proceed past an entry set of loupes, while others will jump from low-power loupes to a microscope without using a medium

19 Incorporating Magnification Into Your Dental Practice 7 level of magnification. In rare instances, a practitioner will not be able to become proficient with low-power loupes and will jump into a microscope right away. This unusual progression may result from the ergonomic value of the microscope, which allows the clinician to sit upright, thereby relieving back and neck pain, or some clinicians greater ability to acclimate to stereoscopic vision through a microscope than to convergent vision through loupes (Figure 6). The magnification continuum is simply a concept to describe the progression of many clinicians when they begin to appreciate the value of magnification for improving both their work and their posture. This author has progressed through many sets of loupes, including entry level, 3.5 magnification, and 4.5 magnification (Figure 7). However, for many years, all clinical work has been completed through an operating microscope that has six levels of magnification from 2.1 to 19.2 (Figures 8a and 8b). All operatories in the practice have a microscope available for all procedures, and all operatories have been designed to function ideally with the microscope as the centerpiece visually, ergonomically, and functionally (Figures 9a and 9b). The FIGURE 6: VISION THROUGH LOUPES VERSUS MICROSCOPE Loupes Microscope Convergent Vision Versus Stereoscopic Vision Note. Courtesy of Dr. David Clark, Tacoma, Washington. use of higher magnification levels has increased the operator s ability to sit upright. This has been an evolving process, beginning with having the initial loupes properly adjusted for focal distance; later switching from flip loupes to TTL loupes, which have a higher declination angle; and eventually moving to the use of an operating microscope that enables neutral and balanced posture (Figure 10). FIGURE 7: LOUPE PROGRESSION FROM 2.5 FLIP-UP, TO 3.5 FLIP-UP, TO 4.5 EXTENDED FIELD OF VIEW TTL

20 8 Incorporating Magnification Into Your Dental Practice FIGURE 8A: MICROSCOPE WITH SIX MAGNIFICATION LEVELS (2.1, 3.2, 5, 8, 13, 19.2 ) FIGURE 9A: MICROSCOPE-CENTERED OPERATORY A simple one-chip medical grade cube camera (the black square shown on the right-hand side) provides video so that patients can see in real-time during their exams and procedures. FIGURE 8B: DOM WITH THREE-CHIP DIGITAL VIDEO CAMERA (LEFT) AND DIGITAL SINGLE-LENS REFLEX CAMERA (RIGHT) FIGURE 9B: DOM AND MICRO- SURGEON S CHAIR USED FOR RESTORATIVE DENTISTRY IN OPERATORY

21 Incorporating Magnification Into Your Dental Practice 9 FIGURE 10: MAGNIFICATION CONTINUUM FROM NAKED EYE TO DOM Note the improvement in posture. Increasing levels of magnification and longer working distance provide a more neutral and balanced posture. Note. From Western Schools, ADVANTAGES OF USING SURGICAL TELESCOPIC LOUPES IN DENTISTRY The two primary benefits that most clinicians cite for using loupes in dentistry are improvement in ergonomics (Aghilinejad, Kabir-Mokamelkhah, Talebi, Soleimani, & Dehghan, 2016; Hayes, Osmotherly, Taylor, Smith, & Ho, 2014; Wajngarten & Garcia, 2016) and increased precision (Alhazzazi et al., 2017). The perception is that magnification, when properly fitted, will encourage improvements in posture and reduce stress on the neck and back (Figures 11 and 12). Loupe manufacturers claim that properly adjusted loupes result in improved ergonomics, which in turn decrease the risk of debilitating injury to the clinician. Ariëns and colleagues (2001) found that dentists who maintained a forward head position of 20 or more for more than 70% of the time had a higher risk of neck pain. Most dental professionals work with a forward head position of 30 or more for 85% of their time in the operatory. This leads to neck pain in 70% of dentists and dental hygienists (Marklin & Cherney, 2005). The need to see the operating field causes the clinician to lean forward, and because the neck vertebrae cannot support the spine, the stabilizing shoulder muscles are rapidly fatigued and other muscles are eventually used to perform a job they were not designed for. This situation can lead to tension neck syndrome (TNS), with pain in the neck, shoulders, and interscapular muscles. Long-term disc degeneration has been noted as a result of a prolonged forward head position. Similarly, improper adjustment or use of magnification aids can either increase the risk of injury or worsen existing pain. The other advantage of using loupes is the improvement in precision resulting from the increased amount of visual information that magnification and illumination provide to the operator. Unfortunately, there are very few well-designed, peer-reviewed, published scientific studies that show a correlation between enhanced visual acuity and an overall improvement in the quality of care (Hagge, 2003; Park, Chehroudi, & Coil, 2014; Sunell & Rucker, 2004). In fact, although some studies have shown that dental students make fewer errors with loupes (Forgie, Pine, & Pitts, 2001, 2002; Narula, Kundabala, Shetty, & Shenoy, 2015; Zaugg, Stassinakis, & Hotz, 2004), other research is not so definitive in its conclusion of

22 10 Incorporating Magnification Into Your Dental Practice FIGURE 11: DENTAL HYGIENIST WITH IMPROVED POSTURE USING 2.5 TTL LOUPES WITH HEADLAMP FIGURE 12: KEY ERGONOMIC FACTORS TO CONSIDER WITH SURGICAL LOUPES 1. Declination angle 2. Working distance of loupes 3. Forward head position 4. Arm position Note. From Western Schools, a positive impact on quality with magnification (Lussi, Kronenberg, & Mergert, 2003; Neuhaus, Jost, Perrin, & Lussi, 2015). Although the current literature does not support the contention that treatment quality, longevity, or overall prognosis is affected by magnification, the general consensus among clinicians is that their work is improved with surgical magnification and that subsequent increases in the amount of magnification yield improvements in the precision of their work. ADVANTAGES OF USING A DOM As the clinician enters into use of higher magnification levels (4 to 6 powers and above), the choices are limited to heavier and more expensive TTL loupes with headlamps, DOMs, and a few heads-up display systems. Mamoun (2009) has cited the benefits of higher magnifications for all areas of dental practice. A DOM is different from loupes in that it offers true stereoscopic vision (as compared to the convergent vision of loupes as shown in Figure 6). The microscope can be mounted to a ceiling, wall, or floor stand and can also have a mobile base. A DOM employs coaxial illumination (meaning the light pathway is coincident with the visual pathway), which provides intense shadow-free lighting. The microscope has multiple levels of magnification that are easy to access with the turn of a changer ( turret): low (2.1 to 3.2 ), medium (5 to 8 ), and high (13 to 19 ). All ranges of the magnification spectrum can be utilized, depending on procedural needs (Figures 13a, 13b, and 13c). A DOM provides clinicians with four main advantages: (a) improvements in precision of treatment, (b) ergonomic benefits, (c) enhanced communication with patients (through live video), and (d) increased ease of documentation. The application of an operating microscope in clinical dentistry can be traced to Dr. Harvey Apotheker in He converted a medical operating microscope for use in endodontics. Although the device itself was rudimentary it had only one level of magnification and required the operator to stand upright it introduced a concept that would revolutionize the field of endodontics. The work of other early magnification proponents led to the routine use of the microscope in the 1990s (Sachan, Srivastava, & Pandey, 2016) for improvements

23 Incorporating Magnification Into Your Dental Practice 11 FIGURE 13A: 2.1 MAGNIFICATION FIGURE 14: MB1 AND MB2 CANAL (8 MAGNIFICATION) FIGURE 13B: 8 MAGNIFICATION FIGURE 15: PULP CHAMBER OF A LOWER MOLAR FIGURE 13C: 19 MAGNIFICATION in both surgical and standard endodontic therapy. As seen in Figures 14 and 15, the use of DOMs in endodontics has been shown to improve the ability to uncover more pulpal anatomy as compared to the use of lesser levels of magnification or lower-power loupes (Barletta, Dotto, Reis, Ferreira, & Travassos, 2008). After the introduction of microscopes in endodontics, there was a spike of interest in DOMs for periodontics, where their routine use could enable more delicate procedures in a microsurgical armamentarium, including smaller blades and 7-0 to 10-0 sutures. These delicate surgical procedures allowed for decreases in postoperative pain and quicker healing (Hegde, Sumanth, & Padhye, 2009; Mallikarjun, Devi, Naik, & Tiwari, 2015). During the 1990s a small group of restorative dentists, many with an active interest in endodontics, started to incorporate the microscope as an important part of the armamentarium in general practice. For these dentists, the microscope became an integral part of all dental procedures because they discovered that the dramatic improvement in visual information provided by a DOM (Figures 16 through 21) allowed for a level of precision in both diagnosis and treatment outcomes that were not previously possible. Since then, the microscope s value has been established in all areas of dentistry.

24 12 IGURE 16: EARLY OCCLUSAL F CARIES (13 MAGNIFICATION) Incorporating Magnification Into Your Dental Practice IGURE 19: EVALUATING F IMPRESSIONS (13 MAGNIFICATION) IGURE 17: CRACKED TOOTH F (13 MAGNIFICATION) IGURE 18: VENEER PREPS F (5 MAGNIFICATION) IGURE 20: CROWN PREP F (13 MAGNIFICATION) IGURE 21: VENEER CEMENT F REMOVAL (19 MAGNIFICATION) In addition, an operating microscope provides important ergonomic benefits (Perrin et al., 2016). The clinician sits in a comfortable upright position, relying on directed patient movements or mirror movements to visualize the surgical site (Figure 22). If the operating microscope is properly adjusted, the clinician can look straight ahead, with little forward head rotation. If the operator uses a microsurgeon s chair to support

25 Incorporating Magnification Into Your Dental Practice 13 FIGURE 22: ERGONOMIC BENEFITS OF USING A MICROSCOPE FIGURE 23: ACCESSIBILITY BENEFITS OF USING A MICROSCOPE 1. Declination angle 2. Objective lens distance 3. Forward head position 4. Arm position Note. From Western Schools, the gross motor joints (shoulders and forearms), precise micromotor movements can be completed (shown in Figure 9b). The clinician s balanced position when using the microscope may help reduce musculoskeletal injuries that are common among dental practitioners (Valachi & Valachi, 2003a, 2003b). Additional research is needed to determine whether the ergonomic benefits of using a microscope are superior to those of well-adjusted loupes; however, there have been several cases in which clinicians who have had severe neck pain, degenerative disc disease, or, in at least one instance (Figure 23), spinal injury, have been able to return to work by introducing an operating microscope into their practice. In addition to the ergonomic benefits, dentists who use an operating microscope have discovered that it can be used to provide both patients and auxiliary staff with the ability to observe treatment in real time. This is accomplished by attaching to the microscope either a medicalgrade cube video camera (shown in Figures 8a and 8b) or a slightly heavier high-definition digital camcorder (shown in Figure 24). The ability to bring a dental assistant into the micro world is possible when the video from the microscope is connected to an LCD monitor. This helps both to aid in instrument passages and to prevent the Dr. Rex Hawthorne of Vernon, British Columbia, paralyzed from the waist down in a mountain biking accident, was able to return full time to a private dental practice with a specially designed wheelchair, an operating microscope, and a tremendous amount of desire. FIGURE 24: BENEFITS OF USING VIDEO WITH A MICROSCOPE Attachment of a digital camcorder to the operating microscope allows procedures to be documented in video format and transferred to monitors in the operatory. dental assistant from being inadvertently blinded by reflections of the microscope light off an intraoral mirror.

26 14 Incorporating Magnification Into Your Dental Practice Patients can watch the video overhead via connection to an LCD monitor or television and follow along with the procedure. The advantages to this arrangement are that patients tend to hold still and are educated about the complexity of the procedure by observing the treatment as it progresses. There are a multitude of benefits to integrating video with a microscope (Sayed, Ranna, Padawe, & Takate, 2016; van As & Napoletano, 2007). Research has long shown that as much as 55% of the understanding that occurs in verbal communication is obtained through visual cues, and only 7% of the comprehension in communication comes from the words we use (Mehrabian & Ferris, 1967). Stated differently, patients remember more of what they see than what they hear. Consequently, clinicians have found that the images from an operating microscope are a benefit in educating patients about their treatment needs. The ability to easily document a procedure using digital micro photography and microvideography with cameras attached to an operating microscope opens up new possibilities for patient education and for documentation for professional presentations and medical and legal purposes. The cost of an operating microscope ranges from $5,000 to $50,000, depending on the manufacturer, the number of magnification steps, and the various options and accessories chosen. The newest technology in the magnification arena is the heads-up display, which involves a camera being placed over the patient and projecting the image to a monitor. The projection of images either two-dimensional (2-D) or three-dimensional (3-D) may help reduce the learning curve that has been associated with operating microscopes (Friedman, 2004). The benefits of heads-up displays include possible improvements in ergonomics, treatment outcomes, and communication through documentation with video and captured still photographs (Margolis, 2008). In many cases, these systems are more expensive than an operating microscope and range in price from $15,000 to $30,000, with the 3-D system being more expensive as well (Figure 25). FIGURE 25: PROJECTION OF 3-D IMAGES A 3-D heads-up display where the operator works in 3-D with glasses while looking at a monitor. Four highdefinition cameras supply the image to the monitors for both the clinician and dental assistants.

27 Incorporating Magnification Into Your Dental Practice 15 CHALLENGES OF INCORPORATING MAGNIFICATION INTO DAILY PRACTICE There are challenges any time a practitioner incorporates new technology into a practice, and magnification is no different. Purchasing any type of magnification represents a start-up cost. Typically, loupes are less expensive than an operating microscope or a heads-up display system. The price of magnification can be significant when equipping multiple operatories or purchasing more than one set of loupes. Most clinicians agree that the first set of loupes will likely not be the last, and clinicians who fully integrate microscopes into their offices often discover that one microscope is not enough if multiple operatories are employed. The learning curve is usually shorter when incorporating lower levels of magnification into a practice. For this reason, it is advisable for clinicians to purchase initial loupes in the 2 to 3 magnification range. However, many factors affect the length of the learning curve, including the pace at which a practitioner usually functions and his or her ability to get used to the slower initial pace that results from the increased amount of visual information being seen and processed. Another consideration is the magnification scotoma (blind zone) that impairs peripheral vision with loupes (van As, 2013b). This blind zone increases with the power of magnification; with loupes, this problem can be best overcome by subtle repositioning of the head. In the case of an operating microscope, operators must learn to move themselves less and rely on repositioning the dental chair, the patient s head, or the mirrors. The magnification scotoma lengthens the time it takes for a clinician to achieve microscope integration; it may take months for the clinician to achieve proficiency with all magnifications in all areas of the mouth. Many clinicians are concerned with the perception that patients, including children, will find the magnification systems peculiar. However, even microscopes and heads-up displays have been integrated into pediatric practices (Kotlow, 2004). Finally, there is a concern that full integration of magnification into a dental practice will foster a level of dependency on this technology. There is no evidence in either the dental or medical literature to suggest that a consistent use of loupes will create a weakness or deterioration of natural eyesight. As previously mentioned, clinicians who are in their 40s will naturally encounter difficulty with presbyopia, which necessitates the use of reading glasses for closeup viewing. SUMMARY Medical healthcare professionals have relied on enhanced visual acuity to improve treatment outcomes for many years. However, the dental profession has been slower to adopt magnification. As a result of an increased understanding of the benefits of enhanced visual acuity, many dental schools and dental hygiene programs now require magnification equipment and techniques to be part of a student s education. Dentistry is both physically and mentally challenging on a daily basis, and the recent rapid influx of new equipment, techniques, and materials has made dentistry even more demanding. The incorporation, proper setup, and use of magnification in regular daily practice can alleviate a practitioner s neck and back pain, aid in treatment outcomes, and assist in documentation and patient communication. Because dental practitioners cannot treat what they cannot see, they should not hesitate to