Prevalence of Second Canal in Mandibular Incisors in CBCT and Periapical Radiography

Background & aim: Accurate knowledge of root canal morphology is essential for standard endodontic treatment. Mandibular incisor teeth are usually single-rooted and single-canal, but sometimes have a second canal that, if left untreated, can lead to failure of endodontic treatments. Therefore, the aim of the present study was to determine and compare the accuracy of periapical radiography with CBCT in observing the second channel in mandibular incisors. Methods: The present study was a cross-sectional analytical research and fitted to correlation schemes in terms of data collection and analysis methods. The statistical population consisted of 292 periapical radiographs and CBCT of mandibular incisor teeth in 73 patients (including 41 females and 32 males). All patients were required to prepare these images for their treatment process. Radiographs were evaluated by two trained dental students in axial, coronal and cross-sectional sections. The number of lower incisors and their shape were recorded according to Vertuccichr('39')s classification for dental canal morphology. If there was any disagreement between the two students, the radiologist was consulted to make the final decision. Data were analyzed using t-test. Results: CBCT examination indicated that 78.4% of mandibular incisors were single-canal and in the rest two-channel, but in periapical radiographic examination none of the teeth exposed the presence of two channels. Central teeth had more cases of two canals than lateral and male teeth compared to women. In Vertuchi classification, among the two-canal teeth, the highest prevalence was related to type four (6.4%) and the lowest prevalence was related to type three (4%). Conclusion: Although periapical radiography is a routine procedure for endodontic treatment, CBCT radiography should be used when endodontic treatment fails or a second canal is present.