May 24-30, 201022 Clinical United Kingdom Edition internal micro-morphology of the root complex were epi- demiologically similar, then “imprinting” of the canal preparation would be logical. Unfortunately, such is not the case (59) . Figure 16b shows how the use of hand files in the apical third can alter the prelimi- nary shape created by the NiTi files. Hand files have a .02 ta- per (along the shaft of the file, the diameter increases by .02 mm per mm of length - .20 file with 16 mm of flutes would be measure .52 mm at the coro- nal end of the flutes). In the example shown, a #20 file is positioned at the minor apical diameter. Careful positioning of a series of file within the last mm can produce a .2 mm or 20 per cent taper with no undue disruption of the native anatomy. Schilder’s precept for shaping was to keep the api- cal foramen as small as prac- tically possible. Whatever file approximates the minor apical diameter, in conjunction with hand filing, the apical control sone created will enhance the apical seal as the rheologic vectors of compaction and condensation have a greater lateral volume of displacement at the terminus. Fashioning a risk assess- ment algorithm If the biologic parameters that mandate endodontic success are adhered to, in almost all cases, treatment outcomes will be successful. The endodontic implant algorithm processes the array of contributing fac- tors leading to endodontic failure, in order to determine whether to implement a re-en- gineered endodontic approach or to extract and replace the natural tooth with an osseo- integrated implant. It finds the greatest common divisor among the degree of coronal breakdown of the involved or adjacent teeth, the quality and quantity of the bone support and tissue condition, the en- gineering demands to be born by the tooth or teeth in ques- tion and assesses the occlusal scheme and the patient’s aes- thetic and functional expecta- tions of treatment. Thereasonsfortoothextrac- tion may include, but are not limited to, crown to root ratio, remaining root length, peri- odontal attachment lev- els, furcation status, peri- odontal health of teeth adjacent to the proposed fixture site and non-restor- able carious destruction. In addition, the clinician must consider questionable teeth in need of endodontic treatment, teeth requiring root amputa- tions, hemi-sections or ad- vanced periodontal procedures with a questionable prognosis and pulpless teeth fractured at the gingival margin with roots shorter than 13mm. These teeth will require endodontic treatment, crown lengthening, post/cores and crowns; how- ever, their longevity is very much in doubt with these pa- rameters (60) . Practitioners are ethically obligated to inform patients of all reasonable treatment options. It is the patient’s atti- tude, values and expectations that are integral to the risk assessment algorithm. Poor motivation to retain a tooth mandates extraction, not clini- cal intervention whereas high motivation advocates non-sur- gical intervention or surgery. The process of planning, pres- entation and acceptance of dental treatment plans is al- ways dominated by the dual- ity of emotion and pragmatism associated with cost. Where it becomes specious is the side- by-side dollar comparison of restoring a natural tooth or placement of a fixed bridge et al in contrast to ortho- biologic replacement of a debilitated tooth. Far too often the compari- son of purported treatment outcome percentages are based upon corporate affilia- tion and/or fiduciary bias, or are simply too narrow a pa- rameter to suggest comparable alternatives. With the treat- ment options available to an experienced endodontist, only a very few structurally sound teeth need be removed. DT Fig 16b – Modification of taper in last mm of the apical terminus, exaggerates the “constric- tion” or minor apical diameter. Thermo-labile vertical condensation has been shown to enhance successful endodontic outcomes. The matrix effect of the apical control zone enhances the gravi- tometric density of the required hermetic apical seal as well as enabling more material to flow into the region to occlude fins, cul-de-sacs, deltas and lateral arborisations. About the author Kenneth S Se- rota, DDS, MMSc graduated from the University of Toronto, Faculty of Dentistry in 1973 and was awarded the George W Swit- zer Memorial Key for excellence in Prosthodontics. He received his Certificate in Endodontics and Master of Medical Sciences De- gree from the Harvard-Forsyth Dental Center in Boston, MA. The founder of ROOTS – an online educational forum for dentists from around the world who wish to learn cutting edge endo- dontic therapy, he recently launched IMPLANTS (www.rximplants.com) and www.tdsonline.org in order to provide a clear understanding of the endodontic/implant algorithm in foun- dational dentistry. page 20DTß References 1. Farzaneh M, Abitbol S, Lawrence H, Friedman S. Treatment Outcome in Endodontics—The Toronto Study. Phase II: Initial Treatment. J Endod 2004 May;30(5):302-309. 2. Bero L, Rennie D. The Cochrane Collaboration. Preparing, maintaining, and disseminating systematic reviews of the effects of health care. JAMA 1995 Dec;274(24): 1935-1938. 3. Salehrabi R, Rotstein I. Endodontic treatment outcomes in a large patient population in the USA: an epidemiologi- cal study. J Endod 2004 Dec;30(12):846-50. 4. Cagidiaco MC, García-Godoy F, et al. Placement of fiber prefabricated or custom made posts affects the 3-year survival of endodontically treated premolars. Am J Dent 2008 Jun;21(3):179-84. 5. Dietschi D, Duc O, Krejci I, Sadan A. Biomechanical considerations for the restoration of endodontically treated teeth: a systematic review of the literature, Part II (Evaluation of fatigue behavior, interfaces, and in vivo studies). Quintessence Int 2008 Feb;39(2):117-29. 6. Aquilino SA, Caplan DJ. Relationship between crown placement and the survival of endodontically treated teeth. J Prosthet Dent 2002 Mar;87(3):256-63. 7. Dorn SO, Moodnik RM, Feldman MJ, Borden BG. Treatment of the endodontic emergencies: A report on a questionnaire. Part I. J Endod 1977;3:94 –100. 8. Gatewood RS, Himel VT, Dorn SO. Treatment of the endodontic emergency: A decade later. J Endod 1990;16:284 –91. 9. Siqueira, J F. Endodontic infections: Concepts, paradigms, and perspectives. OS, OM, OP, OR & Endo Sept 2002;94(3):281-293. 10. Siqueira JF Jr, Guimarães-Pinto T, Rôças IN. Effects of chemomechanical preparation with 2.5% sodium hypochlorite and intracanal medication with calcium hydroxide on cultivable bacteria in infected root canals. J Endod. 2007 Jul;33(7):800-5. 11. Baumgartner JC, Hutter JW, Siqueira JF. Endodontic Microbiology and Treatment of Infections. In: Cohen S, Hargreaves KM, editors. Pathways of the Pulp. Ninth ed. St. Louis: Mosby; 2006. 12. Baumgartner JC, Xia T. Antibiotic susceptibility of bacteria associated with endodontic abscesses. J Endod 2003;29(1):44-47. 13. Khemaleelakul S, Baumgartner JC, Pruksakorn S. Identification of bacteria in acute endodontic infections and their antimicrobial susceptibility. Oral Surg Oral Med Oral Pathol 2002;94(6):746-55. 14. Grondahl H-G, Huumonen S. Radiographic manifestation of periapical inflammatory lesions. Endodontic Topics 2004;8:55-67. 15. Scarfe WC, Farman AG, Sukovic P. Clinical applications of cone-beam computed tomography in dental practice. JCDA 2006;72:75-80. 16. Pinksy HM et al. Accuracy of three-dimensional measurements using cone-beam CT. Dentomaxillofacial Radiology 2006;35:410-6. 17. Iwai et al. Estimation of effective dose from limited cone beam x-ray CT examination. Dental Radiology (Japanese) 2001;50:251-9. 18. Patel S, Dawood A, Whaites E, Pitt Ford T. The potential applications of cone beam computed tomography in the management of endodontic problems. Int EndoJournal 2007;40:818-30. 19. Estrela C. Accuracy of Cone Beam Computed Tomography and Panoramic and Periapical Radiography for Detection of Apical Periodontitis. J Endo 2008;34(3):273-279. 20. Simon JHS, Enciso R, Malfaz JM, Rogers R, Bailey-Perry M, Patel A. Differential diagnosis of large periapical lesions using cone-beam computed tomography measurements and biopsy. J Endod 2006;32:833–7. 21. Iqbal MK, Johansson AA, Akeel RF, Bergenholtz A, Omar R. A retrospective analysis of factors associated with the periapical status of restored, endodontically treated teeth. Int J Prosthodont 2003;16:31– 8. 22. Siqueira JF Jr, Rocas IN, Favieri A, Abad EC, Castro AJ, Gahyva SM. Bacterial leakage in coronally unsealed root canals obturated with 3 different techniques. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2000;90:647–50. 23. Schwartz RS, Fransman R. Adhesive Dentistry and Endodontics: Materials, Clinical Strategies and Procedures for Restoration of Access Cavities: A Review. J Endod March 2005;(31)3:151-165. 24. Zehnder M, Kosicki D, et al. Tissue-dissolving capacity and antibacterial effect of buffered and unbuffered hypochlorite solutions. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology & Endodontics;(94):756-762. 25. Sjogren U, Figdor D, Persson S, Sundqvist G. Influence of Infection at the time of root filling on the outcome of endodontic treatment of teeth with apical periodontitis. Int Endo Journal Sept 1997;(30)5:297-306. 26. Siqueira JF, Rôças IN, et al. Chemomechanical Reduction of the Bacterial Population in the Root Canal after Instrumentation and Irrigation with 1%, 2.5%, and 5.25% Sodium Hypochlorite. J EndodonJune 2000;(26)6:331-334. 27. Torabinejad M, Cho Y, Khademi AA, Bakland LK, Shabahang S. The effect of various concentrations of sodium hypochlorite on the ability of MTAD to remove the smear layer. J Endod 2003;(29):233–239. 28. Siqueira JF Jr, Rocas IN, Santos SR, Lima KC, Magalhaes FA, de Uzeda M. Efficacy of instrumentation techniques and irrigation regimens in reducing the bacterial population within root canals. J Endod 2002;28:181–184. 29. Niu W, Yoshioka T, Kobayashi C, Suda H. A scanning electron microscopic study of dentinal erosion by final irrigation with EDTA and NaOCl solutions. Int Endod J 2002;35:934–939. 30. Lin LM, Rosenberg PA, Lin J. Do procedural errors cause endodontic treatment failure? JADA 2005;(136) 2:187-193. 31. De-Deus G et al. Dye extraction results on bacterial leakproof root fillings. J Endo Sept 2008;(34)9:1093-5. 32. Barthel CR, Moshonov J, Shuping G, Orstavik D. Bacterial leakage versus dye leakage in obturated root canals. Int Endod J 1999;32:370 –5. 33. Kersten HW, Moorer WR. Particles and molecules in endodontic leakage. Int Endod J 1989;22:118-24. 34. Oliver CM, Abbott PV. Correlation between clinical success and apical dye penetration. Int Endod J 2001;34:637-44. 35. Paqué F, Sirtes G. Apical sealing ability of Resilon/Epiphany versus gutta-percha/AHPlus: immediate and 16-months leakage. Int Endod J. 2007 Sep;40(9):722-9. 36. Cruse WP, Bellizzi R. A historic review of endodontics 1689-1963, Part I. J Endod,1980; 6:495-499. 37. Blaney JR. The biologic aspect of root canal therapy. Dental Items of Interest 1927;49:681-708. 38. Schilder H. Filling root canals in three dimensions. Dental Clinics of North America 1967;723-44. 39. Ingle H: Endodontics, ed 5, Hamilton, London, 2002 BC Decker. 40. Wu MK, Fan B, Wesselink PF. Leakage along apical root fillings in curved root canals. I. Effects of apical transportation on seal of root fillings J Endodon 2000;(26):210. 41. Siqueira JF Jr. Aetiology of the endodontic failure: why well-treated teeth can fail. Int Endod J 2001;34:1–10. 42. Roggendorf et al. Bacterial leakage in filled root canals using four root canal sealers. IEJ Dec 2007;40(2): Abstract R3.86. 43. Roedl et al. Bond strength to root canal dentine following different irrigation protocols using a new testing method. IEJ Dec 2007;(40)12:Abstract R3.66. 44. Raina R et al. Evaluation of the Quality of the Apical Seal in Resilon/Epiphany and Gutta-Percha/AH Plus–filled Root Canals by Using a Fluid Filtration Approach J Endod;(33)8:944-47. 45. Teixeira FB, et al. Fracture resistance of roots endodontically treated with a new resin filling material. JADA 2004;(135)5:646-652. 46. Sly MM, Moore BK, Platt JA, Brown CE. Push-out bond strength of a new endodontic obturation system (Resilon/Epiphany). J Endod. 2007 Feb;33(2):160-2. 47. Williams C, Loushine R et al. A Comparison of Cohesive Strength and Stiffness of Resilon and Gutta-Percha. J Endod 2006;(32)6:553-5. 48. Tay F, Loushine R et al. Ultrastructural Evaluation of the Apical Seal in Roots Filled with a Polycaprolactone-Based Root Canal Filling Material. J Endod 2005;(31)7:514-19. 49. Kapalas A, Lambrianidis T. Factors associated with root canal ledging during instrumentation. Endod Dent Traumatol 2000;16:220–231. 50. Souza, RA. Clinical and radio- graphic evaluation of the relation between the apical limit of root canal filling and success in Endodontics. Part 1 Braz Endod J 1998;3:43-48. 51. AL-Omari MAO, Dummer PM. Canal blockage and debris extrusion with eight preparation techniques. J Endod 1995;21:154-158. 52. McKendry DJ. Comparison of balanced forces, endosonic, and step-back filing instrumentation techniques: quantification of extruded apical debris. J Endod Jan 1990;16(1):24-7. 53. Mullaney TP. Instrumentation of finely curved canals. Dent Clin North Am 1979;23:575–92. 54. Morgan LF, Montgomery S. An evaluation of the crown-down pressureless technique. J Endod 1984;10:491–8. 55. M. Al-Omari, P. Dummer. Canal blockage and debris extrusion with eight preparation techniques. J Endod 2006;21(3):154-158. 56. P. Hankins, M. ElDeeb/ An evaluation of the canal master, balanced-force, and step-back techniques. J Endod 1996;22(3):123-130. 57. Siqueira J, Araújo M, Garcia P, Fraga R, Dantas C. Histological evaluation of the effectiveness of five instrumentation techniques for cleaning the apical third of root canals. J Endod 1997;23(8): 499-502. 58. Serota KS et al. Predictable endodontic success: The apical control zone. Dentistry Today May 2003;(22)5:90-7. 59. Peters OA, Peters C, et al. ProTaper rotary root canal preparation: effects of canal anatomy on final shape analysed by micro CT. Int Endo J February 2003;(36)2:86-92. 60. Becker W. Immediate implant placement: Diagnosis, treatment planning and treatment steps for successful outcomes. J Calif Dent Assoc 2002;33:303-310 Fig 16a- The ProTaper Universal System comprises two shaping files that address the planes of geometry of the coronal and middle thirds of the root canal space. There are five finishing files that include tips sizes, 20, 25, 30, 40 and 50. Tapers range from .06 to .09 through the series. A thor- ough understanding of the metrics is essential for the preparation of the myriad variations in inter- nal micro-morphology of the root canal space and the assurance of minimal iatrogenic impact.

Please activate JavaScript!
Please install Adobe Flash Player, click here for download