AIM: The aim of the present study was to evaluate the number of roots and the anatomy of root canal systems of permanent mandibular premolars using images derived from cone-beam computed tomography (CBCT) scans.
METHODS: Mandibular CBCT scans of a cohort of Caucasians (Italians) were evaluated using a dedicated software. The number of roots and the anatomy of root canal systems (following the classification by Vertucci) were recorded, and the prevalence of each type was calculated.
RESULTS: In total, 112 mandibular scans were evaluated accounting for 97 first premolars and 88 second premolars; 94.2% of first premolars and 96.6% of second premolars had one single root. The most common root canal system configuration was type I for both first premolars (79.2%) and second premolars (95.5%). Moreover, a large variability was observed.
CONCLUSIONS: Based on the results, mandibular premolars show a significant heterogeneity in root canal system anatomy that could complicate non-surgical endodontic treatment.