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Dental Tribune Middle East & Africa Edition | 1/2017 14 CONE BEAM For more information www.jordan.no jordndub@emirates.net.ae Tel no.: 04-8871050 Expert Clean, the best from Jordan GumCare™ bristles -Gentle and effective gum clean ActiveTip -Effective reach of back molars Different heights Criss-cross angled bristles -Effective reach of back molars Jordan Expert Clean Proven effective clean CBCT aided detection of 7 root canals in a first maxillary molar ByDrAntonisChaniotis,Greece Introduction The root canal system of the human teeth consists of a complex anasto- motic and highly variant network of pulpspacesasseeninmicro-ctstud- ies of root canal anatomy (http:// rootcanalanatomy.blogspot.com/) (Fig. 1). The thorough cleaning and shaping of this complicated system is considered mandatory for the successful endodontic treatment. The subsequent complete obtura- tion of the cleaned and shaped root canal system with an inert material followed by the appropriate coronal restoration are two important pa- rameters for the longevity of the en- dodontically treated tooth. Failure to adequately clean, shape and fill this anastomotic system to all its dimen- sions is a major cause of post treat- mentdisease. Walton & Vertucci, introducing con- cepts of internal pulpal anatomy, stated that lack of thorough knowl- edgeofrootcanalmorphologyranks second as a cause of treatment fail- ures, only to errors in diagnosis and treatmentplanning.Thismeansthat having a working knowledge of the number of roots, number of canals per root and their location, longi- tudinal and cross-sectional shapes, most frequent curvatures and root outlines in all dimensions is essen- tialinordertoprovidehighstandard endodontictreatment. Historically, the evaluation and di- agnosis of the anatomy of the root canal system in a clinical set up was achieved mostly with conventional intraoral periapical radiographs. Nevertheless, they weren’t com- pletely reliable because of their in- herent limitations associated with the two-dimensional imaging. Re- cently, the application of further analytic diagnostic tools such as CBCT scanning for the assessment of unusual root canal morphology has provided three-dimensional im- aging, aiding the correct endodontic management of complicated and challenging cases. The CBCT data has become a particularly useful tool in assessing the root and canal mor- phologyofcomplicatedcases. In the present paper, the endodon- tic treatment of a first maxillary molar with complicated root canal anatomy is reported. The pre-surgi- cal use of CBCT imaging in combi- nation with the surgical operating microscope led to the detection and negotiation of 7 root canal systems in a single tooth. The aim of the pre- sent case report is to highlight the importance of cbct imaging in as- sessing the root canal morphology of complicated cases. The use of the surgicaloperatingmicroscopeisalso discussed. Casereport A 45-years-old Caucasian male was referred to our Endodontic Private Practice Clinic for the endodontic treatment of his right maxillary first molar. At the time of the appoint- ment, clinical examination revealed an intraoral swelling on his right maxillary quadrant. The patient was under amoxicillin regimen (1gr every 8 hours) for seven days. His medical history was noncontribu- tory. Further clinical examination revealed a heavily restored percus- sion sensitive first maxillary molar. Thermal and electrical vitality tests were negative, suggesting a pulpal diagnosis of pulp necrosis. Periodon- tal probing was within normal limits all around the tooth, except from the buccal furcation area. An endo- dontic periodontal communication had been established and purulent drainage was evident through the furcation area. The preoperative per- iapical radiograph (Fig. 2a) revealed a large periapical lesion associated with tooth #16. The outline of the periapical lesion couldn’t be identi- fied from the periapical radiograph. A periapical diagnosis of acute apical abscesswasmade. The patient was prepared for endo- dontic therapy and a rubber dam was placed. Access to the pulp cav- ity was performed using Endo Ac- cess and Endo Z burs (Dentsply Maillefer). Once the pulp cavity has been reached purulent drainage was noticed. After ten minutes, the purulent drainage turned to hemor- rhagic, then to a clearer exudate and finally ceased. Initial access prepara- tion revealed 4 orifices under mi- croscopic visualization (Global G6, Global Surgical Co., USA). Two sepa- rate orifices were located in the me- sio buccal root, one orifice in the dis- tobuccal root and one orifice in the palatal root. The root canal system of the maxillary molar was irrigated by using 6% NaOCl solution with surface modifiers (Canal Pro Extra, Coltene Whaledent). Initial enlarge- ment of the root canal system of the maxillary molar was achieved by us- ing the Hyflex Controlled memory rotary instrumentation (Coltene, Whaledent). The MB1, MB2 and DB canal were enlarged until 30/04 was reached to working length, while the palatal canal until an 40/04. The canals were dried and calcium hydroxide (Ultracal, Ultradent) was used as an interim dressing. Tem- porarization was achieved by using IRM cement (Dentsply). In order to evaluate the situation a decision was made to perform a CBCT imaging of the tooth and the associating peri- apical lesion. The treatment of large periradicular lesions is very likely to demand a combination of conven- tional and surgical techniques. The CBCT three-dimensional imaging of a large periapical lesion is mandato- ry for the proper pre-surgical evalu- ation and planning, especially when the outline of the periapical lesion exceeds the limits of the periapical radiograph. An informed consent was obtained and the patient was referred for a CBCT evaluation and rescheduled. The multi slice CBCT evaluation of the maxilla (NewTom, VGI, 3D, high resolution, slices every 1mm, voxel size 0.25mm) revealed the extend of the periapical lesion (Fig. 2d,e). In- terestingly, when the involved tooth was focused and the morphology was obtained in transverse axial and sagittal sections, cbct scan slices re- vealedsevencanals(threemesiobuc- cal, two palatal and two distobuccal) (Fig. 2b,c,f). In the transverse axial and sagittal slices, the remnants of the calcium hydroxide dressing wereevident.Intheaxialslice25(Fig. 2f), the calcium hydroxide dressing was evident inside the palatal canal. However, a second canal could be identified, devoid of calcium hy- droxide. This finding was consistent with a missed disto palatal canal. Moreover, a second distobuccal canal without calcium hydroxide dressing was evident (Fig. 2f, axial slice25).Thedoublepalatalcanalsys- tem was evident in the sagittal slices as well (Fig. 2c). The third canal in the mesiobuccalrootcanbeseenonlyin the transverse axial slices and not in thesagittalones(Fig.2b,f). CBCT images provided valuable in- formation regarding the canal num- ber and configuration. This informa- tion revealed three additional canals missingfromtheinitialnegotiation. At the second appointment, the patient was asymptomatic and the intraoral swelling had resolved. The tooth was re-accessed under rubber dam isolation and inspected under the microscope (Global G6, Global Surgical Co.). The inspection under the microscope combined with the axialCBCTimagingcreatedareliable map for the detection of the addi- tional canals (Fig. 3a). Initial negotia- tion of the missed MB3 (in the mid- dle between MB1 and MB2), DB2 and DP canals was achieved by using MC K files with extra long handle (VDW, Endodontic Synergy). The MB1, MB2 and DB1 canals were enlarged until a 30/04 rotary Hyflex CM (Coltene) file reached the working length. The Mesiopalatal and distopalatal canals were enlarged until a 40/04 Hyflex CM (Coltene) rotary file reached the working length. The MB3 canal merged with the MB1 canal and was enlargeduntila25/04HyflexCMfile reachedthemergingpoint. The missed DB2 canal was enlarged until a 30/04 hyflex cm rotary file reached the working length. During theinstrumentationtheDB2merged with the DB1 in a ribbon shaped con- figuration. The working length in all canals was determined by using an electronic apex locator (Root ZX, Morita).Apicalgaugingwasachieved with hand files. Irrigation was achieved by using syringe irrigation of 6% NaOCl solution with surface modifiers (CanalProExtra,Coltene/ Whaledent).Thecleansingefficacyof the irrigant was enhanced by using passive ultrasonic irrigation (Fig 3b). Ultrasonic activation of the irrigant in the MB1 canal created streaming of the irrigant solely in the MB3 ca- nal and not in the MB2 canal (MB3 is named the last canal that was de- tected in the middle between the MB1 and MB2). Under microscopic visualization this fact is suggestive of merging canals. CBCT axial and sagittal images in combination with microscopic visualization showed that both the palatal and distobuc- cal root presented with a Vertucci type II canal pattern, whereas the mesiobuccal root showed a Sert and Bayirli type XV canal configuration. The microscopic clinical image of the pulp floor after the completion of the obturation procedures can be seeninfigures3c,dande. An angled postoperative periapi- cal radiograph revealing the canal configurations can be seen in figure 3f. The patient was referred back to his general dentist for appropriate Figure 1. Micro-ct reconstruction of the internal root canal anatomy of a maxil- lary molar tooth (Images from the root canalanatomyproject weredevelopedat the Laboratory of Endodontics of Ribeirao Preto Dental School - University of Sao Paoloforeducationalpurposes) ÿPage 15