(PR074) CBCT Evaluation for the Assessment of the Existence and Treatment of Extra Root Canals in Mandibular Premolars

Objective: This study aimed to evaluate the incidence of treated and untreated root canals observed on pre-operative or intra-operative CBCT scans in mandibular premolars undergoing root canal therapy (RCT).

Methods: CBCT images were taken, and RCTs were performed by postgraduate endodontic residents at the University of Pennsylvania School of Dental Medicine. CBCT scans from 2016 to 2024 were reviewed. Patient charts were included if the mandibular premolar undergoing RCT had a corresponding pre-operative or intra-operative CBCT scans.

Results: A total of 41 mandibular premolars were analyzed, comprising 21 first premolars and 20 second premolars. Among the first mandibular premolars, a second canal was present in seven teeth (33%), and a third canal was identified in one tooth (3%). In cases with two canals, the second canal was clinically located and treated in six out of seven teeth (85%). For the second mandibular premolars, a second canal was present in two teeth (10%), and of these, the second canal was clinically located and treated in one tooth (50%).

Conclusion: CBCT imaging is a valuable tool for assessing canal anatomy and configuration in mandibular premolars undergoing RCT. However, the findings of this retrospective study suggest that, even with CBCT assistance, identification, instrumentation, and obturation of extra root canals remains a clinical challenge.