Advertisement

The Operating Microscope Enhances Detection and Negotiation of Accessory Mesial Canals in Mandibular Molars

      Abstract

      Introduction

      Detection and negotiation of accessory mesial canals in mandibular molars was investigated with the aid of magnifying loupes or the operating microscope.

      Methods

      First and second mandibular molars (n = 96) were mounted in mannequins. Three independent investigators (endodontists) prepared access cavities using 4.5× loupes, attempting to detect and negotiate accessory mesial canals with ultrasonic instruments. If detection or negotiation was unsuccessful, the procedure was continued using the microscope. The location of accessory mesial canals was mapped in relation to the main mesial canals, and their pathway shown with inserted files. The mesial roots were cross-sectioned at three levels to inspect for nonnegotiated accessory mesial canals.

      Results

      With the microscope, the number of detected accessory mesial canals increased from 8 (16%) to 9 (18%) in first molars and from 8 (16%) to 11 (22%) in second molars. Negotiated accessory mesial canals increased from 6 (12%) to 7 (14%) and from 5 (10%) to 9 (18%) in the first and second molars, respectively. All 20 detected accessory mesial canals were located in the mesial subpulpal groove, closer to the mesiolingual canal (45%), in the middle (30%), or closer to the mesiobuccal canal (25%). All negotiated accessory mesial canals merged with one of the main two canals. Cross-sections of the roots confirmed that no accessory canals were present in addition to those negotiated.

      Conclusions

      Within the limitations of this study, more accessory canals were detected and negotiated when using the microscope compared with loupes. This improvement was more pronounced in second molars than in first molars. All negotiated accessory canals merged with either one of the main mesial canals.

      Key Words

      To read this article in full you will need to make a payment

      References

        • Kersten D.D.
        • Mines P.
        • Sweet M.
        Use of the microscope in endodontics: results of a questionnaire.
        J Endod. 2008; 34: 804-807
        • Lee M.
        • Winkler J.
        • Hartwell G.
        • et al.
        Current trends in endodontic practice: emergency treatments and technological armamentarium.
        J Endod. 2009; 35: 35-39
        • Saunders W.P.
        • Saunders E.M.
        Conventional endodontics and the operating microscope.
        Dent Clin North Am. 1997; 41: 415-428
        • Stropko J.J.
        Canal morphology of maxillary molars: clinical observations of canal configurations.
        J Endod. 1999; 25: 446-450
        • de Carvalho M.C.
        • Zuolo M.L.
        Orifice locating with a microscope.
        J Endod. 2000; 26: 532-534
        • Gorduysus M.O.
        • Gorduysus M.
        • Friedman S.
        Operating microscope improves negotiation of second mesiobuccal canals in maxillary molars.
        J Endod. 2001; 27: 683-686
        • Schwarze T.
        • Baethge C.
        • Stecher T.
        • et al.
        Identification of second canals in the mesiobuccal root of maxillary first and second molars using magnifying loupes or an operating microscope.
        Aust Endod J. 2002; 28: 57-60
        • Baldassari-Cruz L.A.
        • Lilly J.P.
        • Rivera E.M.
        The influence of dental operating microscope in locating the mesiolingual canal orifice.
        Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2002; 93: 190-194
        • Buhrley L.J.
        • Barrows M.J.
        • BeGole E.A.
        • et al.
        Effect of magnification on locating the MB2 canal in maxillary molars.
        J Endod. 2002; 28: 324-327
        • Sempira H.N.
        • Hartwell G.R.
        Frequency of second mesiobuccal canals in maxillary molars as determined by use of an operating microscope: a clinical study.
        J Endod. 2000; 26: 673-674
        • Hess W.
        • Zurcher E.
        The anatomy of the root canals of the teeth of the permanent and deciduous dentitions.
        William Wood & Co, New York1925
        • Skidmore A.E.
        • Bjorndal A.M.
        Root canal morphology of the human mandibular first molar.
        Oral Surg Oral Med Oral Pathol. 1971; 32: 778-784
        • Pineda F.
        • Kuttler Y.
        Mesiodistal and buccolingual roentgenographic investigation of 7,275 root canals.
        Oral Surg Oral Med Oral Pathol. 1972; 33: 101-110
        • Pomeranz H.H.
        • Eidelman D.L.
        • Goldberg M.G.
        Treatment considerations of the middle mesial canal of mandibular first and second molars.
        J Endod. 1981; 7: 565-568
        • Martinez-Berna A.
        • Badanelli P.
        Investigacion clinica de molars inferiors con cinco conductos.
        Boletin de Informacion Dental. 1983; 43: 27-41
        • Vertucci F.J.
        Root canal anatomy of the human permanent teeth.
        Oral Surg Oral Med Oral Pathol. 1984; 58: 589-599
        • Fabra-Campos H.
        Unusual root anatomy of mandibular first molars.
        J Endod. 1985; 11: 568-572
        • Fabra-Campos H.
        Three canals in the mesial root of mandibular first permanent molars: a clinical study.
        Int Endod J. 1989; 22: 39-43
        • Goel N.
        • Gill K.
        • Taneja J.
        Study of root canals configuration in mandibular first permanent molar.
        J Indian Soc Pedod Prev Dent. 1991; 8: 12-14
        • Caliskan M.K.
        • Pehlivan Y.
        • Sepetcioglu F.
        • et al.
        Root canal morphology of human permanent teeth in a Turkish population.
        J Endod. 1995; 21: 200-204
        • Gulabivala K.
        • Aung T.H.
        • Alavi A.
        • et al.
        Root and canal morphology of Burmese mandibular molars.
        Int Endod J. 2001; 34: 359-370
        • Gulabivala K.
        • Opasanon A.
        • Ng Y.L.
        • et al.
        Root and canal morphology of Thai mandibular molars.
        Int Endod J. 2002; 35: 56-62
        • Sert S.
        • Bayirli G.S.
        Evaluation of the root canal configurations of the mandibular and maxillary permanent teeth by gender in the Turkish population.
        J Endod. 2004; 30: 391-398
        • Ahmed H.A.
        • Abu-bakr N.H.
        • Yahia N.A.
        • et al.
        Root and canal morphology of permanent mandibular molars in a Sudanese population.
        Int Endod J. 2007; 40: 766-771
        • Navarro L.F.
        • Luzi A.
        • Garcia A.A.
        • et al.
        Third canal in the mesial root of permanent mandibular first molars: review of the literature and presentation of 3 clinical reports and 2 in vitro studies.
        Med Oral Patol Oral Cir Bucal. 2007; 12: E605-E609
        • Mannocci F.
        • Peru M.
        • Sherriff M.
        • et al.
        The isthmuses of the mesial root of mandibular molars: a micro-computed tomographic study.
        Int Endod J. 2005; 38: 558-563
        • von Arx T.
        Frequency and type of canal isthmuses in first molars detected by endoscopic inspection during periradicular surgery.
        Int Endod J. 2005; 38: 160-168
        • Gu L.
        • Wei X.
        • Ling J.
        • et al.
        A microcomputed tomographic study of canal isthmuses in the mesial root of mandibular first molars in a Chinese population.
        J Endod. 2009; 35: 353-356
        • Vertucci F.
        Root canal morphology and its relationship to endodontic procedures.
        Endod Topics. 2005; 10: 3-29
        • Peiris H.R.
        • Pitakotuwage T.N.
        • Takahashi M.
        • et al.
        Root canal morphology of mandibular permanent molars at different ages.
        Int Endod J. 2008; 41: 828-835
        • Kulild J.C.
        • Peters D.D.
        Incidence and configuration of canal systems in the mesiobuccal root of maxillary first and second molars.
        J Endod. 1990; 16: 311-317
        • Weller R.N.
        • Niemczyk S.P.
        • Kim S.
        Incidence and position of the canal isthmus. Part 1. Mesiobuccal root of the maxillary first molar.
        J Endod. 1995; 21: 380-383
        • Mortman R.E.
        • Ahn S.
        Mandibular first molars with three mesial canals.
        Gen Dent. 2003; 51: 549-551
        • Burleson A.
        • Nusstein J.
        • Reader A.
        • et al.
        The in vivo evaluation of hand/rotary/ultrasound instrumentation in necrotic, human mandibular molars.
        J Endod. 2007; 33: 782-787
        • Carr G.B.
        • Schwartz R.S.
        • Schaudinn C.
        • et al.
        Ultrastructural examination of failed molar retreatment with secondary apical periodontitis: an examination of endodontic biofilms in an endodontic retreatment failure.
        J Endod. 2009; 35: 1303-1309