Comparing CBCT and PA Radiography in Showing Mandibular Incisor Canal

Objective: Accurate knowledge concerning root canal morphology is critical in performing standard endodontic treatment.In conventional endodontic treatment, dentists rely on periapical(PA) views as the source of information regarding the number of canals, their shape and potential curvature. It has been suggested that untreated canal anatomy, is the leading cause of endodontic failures. This is especially true in teeth where PA radiography has difficulty showing the number of existing canals. With the advent of cone beam computed tomography (CBCT) dentists were able to see inside the tooth for the first time, viewing the exact root morphology in 3D. Considering that mandibular incisors frequently have two canals (11-68% has been reported in literature), we set out to compare the ability of PA radiography and CBCT in showing mandibular incisor canals.

Method: The study was descriptive involving 30 Patients (120 mandibular incisors) who required CBCT and PA examination as part of their orthodontic procedure. Teeth demonstrating significant external root resorption or incomplete root formation were excluded from the study. Two trained observers examined the CBCT and PA views for each patient and the number of lower incisor canals and their configuration were recorded according to Vertucci’s classification. Spss 17.0 was used to analyze the data.

Result: The results from observing CBCT views showed that the majority of mandibular incisors (71.7%) had one canal with the rest demonstrating 2 canals. Of the different configurations observed, the most frequently occurring was type V (10.8%) followed by type III (8.3%), type II (7.5%) and type IV (4.2%). When PA radiography was observed all incisors demonstrated a single canal.

Conclusion: CBCT can elucidate canal anatomy in mandibular incisors showing both the number and configuration of the canals and thus can be indicated when endodontic treatment has failed and the presence of a second canal is suspected.