Abstract
Objective: To know the prevalence three-rooted mandibular first molars in a Saudi Arabian population by using CBCT. Material and Methods: A total of 428 CBCT scans in the database of the College of Dentistry, Jouf University, Kingdom of Saudi Arabia were analyzed. All well-developed permanent mandibular first molars were analyzed for the presence of extra root in three dimensions and the reconstructed volumetric images by two qualified and experienced observers. The total incidence, distribution and comparison regarding gender, bilateral and unilateral appearance, and the side of occurrences of these permanent three-rooted mandibular first molars were analyzed by the Chi-square test. The level of significance was set at 5%. Results: The CBCT scans of 14 subjects had three rooted mandibular first molars with a prevalence of 3.27%. The prevalence in males and females was 2.96% respectively, with no significant differences between genders (p=0.865). The frequency of bilateral three-rooted mandibular first molars was 1.16%, with unilateral frequencies of 1.40% and 0.70% on the right and left sides, respectively. No significant relationship between sides (p=0.981) and the bilateral prevalence of three-rooted mandibular first molars (p=0.668) was observed. Conclusion: Dental practitioners must be aware of the fact that though it is rare, an extra or third root can be present in mandibular first molars and CBCT can aid in accurate diagnosis of the presence of third root.