Conventional Management of Fractured Endodontic Instruments and Perforations

Transcription

1 Course Number: Conventional Management of Fractured Endodontic Instruments and Perforations Authored by Mohammad Hosein Kalantar Motamedi, DDS, Upon successful completion of this CE activity 1 CE credit hour may be awarded A Peer-Reviewed CE Activity by Dentistry Today is an ADA CERP Recognized Provider. Approved PACE Program Provider FAGD/MAGD Credit Approval does not imply acceptance by a state or provincial board of dentistry or AGD endorsement. June 1, 2006 to May 31, 2009 AGD Pace approval number: Opinions expressed by CE authors are their own and may not reflect those of Dentistry Today. Mention of specific product names does not infer endorsement by Dentistry Today. Information contained in CE articles and courses is not a substitute for sound clinical judgment and accepted standards of care. Participants are urged to contact their state dental boards for continuing education requirements.

2 Conventional Management of Fractured Endodontic Instruments and Perforations LEARNING OBJECTIVES: After reading this article, the individual will learn: Conventional management considerations for fractured endodontic instruments and perforations. Technique for orthograde nonsurgical treatment and retrograde surgical treatment of fractured endodontic instruments and perforations. ABOUT THE AUTHOR Dr. Motamedi is professor of Oral and Maxillofacial Surgery, Trauma Research Center, Baqiyatallah University of Medical Sciences, and attending surgeon, Azad University of Medical Sciences, Tehran, IR Iran. He can be reached at Dr. Motamedi does not report any disclosures. INTRODUCTION File fractures and root perforations during endodontic treatment are complications most frequently associated with aberrant root canal anatomy, canal calcification, anomalous root shapes, and severe root curvatures. Perforations can occur during removal of gutta-percha from drills used for preparation of posts, during root cleaning and shaping, or when attempting to bypass fractured instruments lodged in the root canal system. Teeth with fractured files may sometimes be treated by an orthograde approach from within the root canal system. Bypassing fractured files has been more successful when the instrument was lodged in the coronal or middle part of the root. However, a perforated tooth with a curved root canal which cannot be negotiated, or one associated with an apical lesion, often requires a retrograde approach in order to create successful obturation. This article describes effective conventional techniques for treating such teeth. BACKGROUND Continuing Education Recommendations for Fluoride Varnish Use in Caries Management Teeth difficult to treat endodontically include teeth with dilacerated or calcified canals. Due to difficult canal morphology, treatment may result in under-filling, root perforation, or inadvertent instrument fracture within the canal. Although under-filling or a fractured instrument in the root canal may not be a problem in vital teeth, it may lead to problems in necrotic teeth or those with an apical lesion. 1-3 Regardless, retreatment interventions are often fraught with mishaps, namely, root perforations. Although such complications may occur in all types of teeth and during the various stages of endodontic treatment, they are more common in teeth with anomalous root canal anatomy, narrow canals, abnormally-positioned teeth, and teeth with root curvatures. 1-3 Perforations may also occur during removal of guttapercha for preparation of post space, root canal cleaning and shaping, or while attempting to bypass fractured instruments in the root canal system. Procedural errors impede proper treatment of the tooth, compromising the prognosis, especially in teeth with necrotic pulps or periradicular lesions. 1-5 While some teeth with fractured files or perforations may be treated orthograde from within the canal, a perforated tooth with a curved root which cannot be negotiated and is associated with an apical lesion often requires both orthograde and retrograde treatment. Sometimes, teeth with perforations or fractured files are considered hopeless and are needlessly extracted by the dentist, whereas many of these teeth can be successfully treated. 3 ORTHOGRADE BYPASS TECHNIQUE FOR FRACTURED INSTRUMENTS Retrieval of a fractured file fragment from the apical third of curved canals should not be routinely attempted.6 However, when a file is fractured in the middle or upper third of the root canal, treatment may be attempted using an 1

3 orthograde approach from within the canal to bypass the fractured instrument. Figure 1 shows a mandibular right molar in a 22-year-old male that was being treated endodontically for a pulpal exposure. A No. 30 K-file fractured in the middle third of the canal during preparation. A precurved 0.8 K-file was inserted into the root canal until it lodged aside the fractured file segment; then it was rotated 15 to 30 and pulled out. This was patiently repeated until the file was incrementally bypassed (Figure 2). Radiographs were taken during the procedure to confirm that the fractured 0.8 K-file was following the correct path. Once the fractured file segment was bypassed, larger files were used in succession and root canal therapy was continued (Figure 3). After cleaning and shaping, canal obturation was accomplished using gutta-percha and dilute canal sealant. Small gutta-percha points with lateral and apical condensation were placed to complete obturation of the root canal. Figure 1. A No. 30 K-file fractured in the middle third of the mesial-root canal. RETROGRADE TECHNIQUE FOR TREATMENT OF FRACTURED INSTRUMENTS OR PERFORATIONS Sometimes in the course of endodontic treatment perforations may occur during removal of gutta-percha, root cleaning and shaping, attempting to negotiate curved or calcified canals or to bypass instrument fracture in the root canal, or when attempting to salvage the failed endodontic tooth. 3,5,7-9 Such procedural errors impede successful treatment of the tooth, especially in teeth with necrotic pulps or periradicular lesions. 1-5 Some root canals with fractured files or lentulos cannot be bypassed, and when this is attempted, it may lead to root perforation, especially if the root is curved (Figure 4). A perforated canal with a curved root that cannot be negotiated completely orthograde or is associated with an apical lesion often requires surgical treatment to achieve healing (Figure 5). Teeth with perforations or fractured files should not be considered hopeless even though patients may present with pain and swelling in the vestibule and seem difficult to manage. In teeth with apical perforations the canal may be obturated up to the point of the perforation and then treated via retrograde surgery. Treatment for the aforementioned case (Figures 4 and 5) involved a 3 to 4 cm vestibular incision made in the mucosa Figure 2. The file was incrementally bypassed. Figure 3. File segment was bypassed, larger files were used in succession, and root canal therapy was continued. 2

4 several millimeters anterior to the tooth. A full-thickness triangular mucoperiosteal flap was reflected and access was made to the bone. Bone removal was accomplished using an electric drill and a round carbide surgical bur. The dilacerated root tip was removed with a fissure bur to the level of the gutta-percha and examined for seal. The granulation tissue was removed using periodontal curettes. The perforation was found using an explorer, and care was taken not to enlarge the perforation. After isolation of the bony cavity using oxidized cellulose and surgical gauze, the perforation was sealed using a very small amount of zinc-free amalgam, and burnished. After irrigation and removal of the oxidized cellulose the wound was closed routinely with absorbable sutures. Healing was uneventful during the postoperative period and the recall radiograph several months later showed good bone healing in the area (Figure 6). Root-end filling materials such as mineral trioxide aggregate (MTA), Super-EBA, and resins may also be used instead of amalgam. However, when small amounts are needed, there are no statistically significant differences in microleakage. 10 Figure 4. A fractured lentulo that could not be bypassed, and when attempted, led to root perforation. DISCUSSION When endodontically treating teeth with dilacerated or calcified root canals, it is prudent to avoid application of excessive force while negotiating canals, insertion of uncurved files, or the creation of a ledge within the canal. Doing so may result in underfilling, root perforation, or instrument fracture. Use of dull, worn-out files, imprudent filing, or aggressive rotation of files may lead to fracture of instruments or inadvertent iatrogenic root perforation. These mishaps may lead to development of an apical lesion requiring retreatment. 1-3 The prevalence of fracture of nickel-titanium rotary instruments is more frequent than that of hand instruments. 9 Dilacerated or calcified teeth are prone to instrument fracture or perforations. For success in endodontic treatment or endodontic surgery, many factors are essential, such as proper cleaning, shaping, obturation, and sealing of the root canal or perforation. 1 In order to prevent ledging, files of smaller size than the root canal must be chosen. Files should be precurved. New files Figure 5. Perforated tooth with a curved root that could not be negotiated completely orthograde and was associated with an apical lesion requiring surgical treatment. Figure 6. Triangular retrograde amalgam filling (arrow) and bone healing in the area several months later. 3

5 should be used in difficult cases. Copious irrigation with dilute sodium hypochlorite without excessive use of pressure should be employed. Lodging of a file within the canal and rotating it using force (for removal, debridement, cleaning, or shaping) may result in file fracture. A fractured instrument can prevent proper cleaning, shaping, obturation, and sealing of the root canal. To bypass a fractured instrument, an orthograde approach from within the canal may be required. Excessive use of force or failure to follow the root curvature may lead to perforation of the root. A perforated tooth with a curved root that cannot be negotiated orthograde or is associated with an apical lesion will often require surgical treatment. A perforation must be sealed, as should a lateral canal or apical foramen. In small perforations gutta-percha may be sufficient to obturate the perforation internally in conjunction with canal sealers. Larger perforations require filling materials to be placed externally as well. 8 The commonly used materials for this purpose include zinc-free amalgam, MTA, and zinc oxide-based compounds. These materials have passed the test of time. Although many clinicians prefer to use MTA as an external filling material for perforations, the author opts to use zinc-free amalgam in perforations 1 mm or smaller in diameter and in posterior teeth. In anterior teeth, in the aesthetic zone, or in large perforations, MTA or EBA is preferred. CONCLUSION The retrieval or bypass of fractured instruments is more successful in the coronal and middle thirds of a tooth when compared with the apical third of the canal. The file fracture frequency is higher in retreatment cases. 9 Retrieval of a fractured file fragment from the apical third of curved canals should not be routinely attempted. Fractured instruments in the apical third or apical foramen often require surgery. The prevalence of fracture of nickel-titanium rotary instruments is more frequent than that of hand instruments. 9 Management of endodontic mishaps, file fractures, or perforation may be complicated. Consultation with an experienced endodontist and/or oral and maxillofacial surgeon may be warranted. REFERENCES 1. Lin LM, Rosenberg PA, Lin J. Do procedural errors cause endodontic treatment failure? J Am Dent Assoc. 2005;136: West JD. Perforations, blocks, ledges, and transportations: overcoming barriers to endodontic finishing. Dent Today. Jan 2005;24: Motamedi MH. Root perforations following endodontics: a case for surgical management. Gen Dent. 2007;55: Zenobio EG, Shibli JA. Treatment of endodontic perforations using guided tissue regeneration and demineralized freeze-dried bone allograft: two case reports with 2-4 year post-surgical evaluations. J Contemp Dent Pract. 2004;5: Motamedi MHK, Behnia H. Apical surgery. In: Dowlatabadi MA, Motamedi MHK, Behnia H, et al: Textbook of Oral and Maxillofacial Surgery, Tehran, Teymourzadeh Publications, 2000: Souter NJ, Messer HH. Complications associated with fractured file removal using an ultrasonic technique. J Endod. 2005;31: Barnes IE. Repair of perforations. In: Barnes IE. Surgical Endodontics. Norwell, MA: Kluwer Academic Publishers; 1984: Pace R, Giuliani V, Pagavino G. Mineral trioxide aggregate as repair material for furcal perforation: case series. J Endod. 2008;34: Tzanetakis GN, Kontakiotis EG, Maurikou DV, et al. Prevalence and management of instrument fracture in the postgraduate endodontic program at the Dental School of Athens: a five-year retrospective clinical study. J Endod. 2008;34: Adamo HL, Buruiana R, Schertzer L, et al. A comparison of MTA, Super-EBA, composite and amalgam as root-end filling materials using a bacterial microleakage model. Int Endod J. 1999;32:

6 POST EXAMINATION INFORMATION To receive continuing education credit for participation in this educational activity you must complete the program post examination and receive a score of 70% or better. Traditional Completion Option: You may fax or mail your answers with payment to Dentistry Today (see Traditional Completion Information on following page). All information requested must be provided in order to process the program for credit. Be sure to complete your Payment, Personal Certification Information, Answers and Evaluation forms, Your exam will be graded within 72 hours of receipt. Upon successful completion of the post-exam (70% or higher), a letter of completion will be mailed to the address provided. Online Completion Option: Use this page to review the questions and mark your answers. Return to dentalcetoday.com and signin. If you have not previously purchased the program select it from the Online Courses listing and complete the online purchase process. Once purchased the program will be added to your User History page where a Take Exam link will be provided directly across from the program title. Select the Take Exam link, complete all the program questions and Submit your answers. An immediate grade report will be provided. Upon receiving a passing grade complete the online evaluation form. Upon submitting the form your Letter Of Completion will be provided immediately for printing. General Program Information: Online users may login to dentalcetoday.com anytime in the future to access previously purchased programs and view or print letters of completion and results. POST EXAMINATION QUESTIONS 1. Teeth with fractured instruments in the root canal: a. must be extracted. b. must be treated orthograde. c. must be treated retrograde. d. may be treated orthograde or retrograde or both depending on the situation, in an attempt to salvage the tooth. 2. Which statement is correct? a. An apical lesion requires retreatment b. The prevalence of fracture of nickel-titanium (Ni-Ti) rotary instruments is more frequent than that of hand instruments c. Fractured instruments in the apical third or apical foramen routinely require surgery in vital teeth d. all of the above 3. Bypassing fractured files has been more successful when the instrument was lodged in the: a. coronal or middle part of the root. b. apical part of the root. c. root cervix. d. posterior teeth. 4. The file fracture frequency is higher: a. in retreatment cases. b. with used files. c. with Ni-Ti rotary instruments. d. all the above. 5. Large perforations require filling materials to be placed: a. externally. b. internally. c. both a and b. d. neither a nor b. 6. Which is essential for successful endodontic treatment? a. cleaning and shaping b. obturation c. sealing the root canal system d. all the above 7. Procedural errors impede proper treatment of the tooth, compromising the prognosis, especially in teeth: a. with necrotic pulps. b. that are nonvital. c. with periradicular lesions. d. all of the above. 8. Access for apical surgery requires a: a. full-thickness mucoperiosteal flap. b. split-thickness mucoperiosteal flap. c. envelope flap. d. none of the above. 5

7 PROGRAM COMPLETION INFORMATION PERSONAL CERTIFICATION INFORMATION: If you wish to purchase and complete this activity traditionally (mail or fax) rather than Online, you must provide the information requested below. Please be sure to select your answers carefully and complete the evaluation information. To receive credit you must answer at least six of the eight questions correctly. Complete online at: Last Name (PLEASE PRINT CLEARLY OR TYPE) First Name Profession / Credentials Street Address License Number TRADITIONAL COMPLETION INFORMATION: Suite or Apartment Number Mail or Fax this completed form with payment to: Dentistry Today Department of Continuing Education 100 Passaic Avenue Fairfield, NJ Fax: PAYMENT & CREDIT INFORMATION: Examination Fee: $20.00 Credit Hours: 1.0 Note: There is a $10 surcharge to process a check drawn on any bank other than a US bank. Should you have additional questions, please contact us at (973) I have enclosed a check or money order. I am using a credit card. My Credit Card information is provided below. American Express Visa MC Discover Please provide the following (please print clearly): City State Zip Code Daytime Telephone Number With Area Code Fax Number With Area Code Address ANSWER FORM: COURSE #: Please check the correct box for each question below. 1. a b c d 5. a b c d 2. a b c d 6. a b c d 3. a b c d 7. a b c d 4. a b c d 8. a b c d PROGRAM EVAUATION FORM Please complete the following activity evaluation questions. Exact Name on Credit Card Credit Card # Signature Dentistry Today is an ADA CERP Recognized Provider. / Expiration Date Approved PACE Program Provider FAGD/MAGD Credit Approval does not imply acceptance by a state or provincial board of dentistry or AGD endorsement. June 1, 2006 to May 31, 2009 AGD Pace approval number: Rating Scale: Excellent = 5 and Poor = 0 Course objectives were achieved. Content was useful and benefited your clinical practice. Review questions were clear and relevant to the editorial. Illustrations and photographs were clear and relevant. Written presentation was informative and concise. How much time did you spend reading the activity & completing the test?