Journal of Dental Medicine

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Background and Aim: A considerable percentage of failure in Endodontic treatments in maxillary molars is attributed to undiscovered second mesiobuccal canal (MB₂).There are different methods for discovering and accessing to this canal. The purpose of this ex vivo study was to compare the detection ability of three methods (direct look, fiberoptic loup and surgical microscope) to find MB₂ after troughing with ultrasonic.

Materials and Methods: In this experimental study, we selected 90 extracted maxillary molars (45 first and 45 second molars) in which after access cavity preparation MB₂ canal was not discovered by direct vision and endodontic explorer. They were divided into 3 groups (n=30). The dentinal shelf between mesiobuccal and palatal canals was eliminated by an endodontic ultrasonic tip (troughing). After that, first group was searched by direct vision, second group by a loup and fiberoptic light and third group by dental operating microscope. Data were analyzed, specificity and sensitivity were calculated.

Results: The results showed that 21%, 61%, and 92% of MB₂ canals after troughing was found by direct vision, fiberoptic loup, and surgical microscope, respectively.

Conclusion: Based on the results of this study, surgical microscope and loup with fiberoptic are preferred methods for discovering MB₂ canal. Troughing with ultrasonic can help find MB₂ canal in all methods.

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Background and Aims: Identification of the second mesiobuccal canal (MB2) in maxillary first molars is considered one of the major challenges in endodontic treatment. This study aimed to investigate the prevalence of missed MB2 canals using cone-beam computed tomography (CBCT).
Materials and Methods: This descriptive-analytical retrospective study was conducted on CBCT images taken in years between 2014 and 2018. The images were selected from patients who had undergone treatment on the maxillary first molars and had visited the radiology department of Borujerd dental school. Inclusion criteria were adequate image quality and presence of root canal treatment, while exclusion criteria included incomplete images and teeth lacking complete treatment. Image analysis was performed by an oral radiology specialist. Sample size was calculated using a statistical formula considering confidence level and study power. Data analysis was performed using descriptive statistics and Spearman’s correlation test in SPSS (version 18) at a significance level of P<0.05.
Results: Out of 90 patients examined, 59 cases (65.5%) had an MB2 canal, of which 56 cases (62.2%) had not been identified during initial treatment. The prevalence of MB2 canals was significantly higher in males than in females (P<0.01). No statistically significant association was found between the presence of periapical radiolucency and MB2 canals. In most cases, the MB2 canal orifice appeared as a separate opening.
Conclusion: The results of this study indicated a high prevalence of missed MB2 canals during initial endodontic treatment. The use of CBCT can play an effective role in detecting these canals and improving the success rate of endodontic therapy. Considering individual characteristics such as gender may aid in more accurate diagnosis.