Prevalence of radix entomolaris and radix paramolaris in mandibular first and second molars in a Turkish population

Abstract

Aim: This retrospective study determined the prevalence and distribution of extra roots (radix entomolaris [RE] and radix paramolaris [RP]) in mandibular first and second molars in a southeastern Anatolian Turkish population using cone-beam computed tomography (CBCT).

Methodology: A total of 2010 mandibular first and second molars from the archived CBCT images of 662 patients (325 males, 337 females) were evaluated for the associations of RE and RP with sex, side, molar type, and unilateral/bilateral presence. Fisher's exact test was used for categorical comparisons and McNemar's exact test for the paired right-left comparison at patient level; prevalences are reported with Wilson score 95% confidence intervals, and the 24 pairwise post-hoc comparisons were corrected for multiplicity by the Holm procedure.

Results: An extra root was detected in 3.7% of the examined teeth (75/2010, 95% CI 3.0-4.7%) and 9.5% of the patients (63/662, 95% CI 7.5-12.0%). Prevalence did not differ significantly by sex (8.9% [29/325] in males versus 10.1% [34/337] in females, p = 0.61), side (McNemar exact p = 0.16), or unilateral/bilateral presence (p = 1.00). Although the overall per-tooth prevalence was similar in first and second molars (3.9% versus 3.6%, p = 0.73), the distribution of root type among the 75 affected teeth differed significantly (Fisher exact p = 0.002). RP was the most frequent type in both first (1.95%, 19/974) and second (3.09%, 32/1036) molars but exceeded RE significantly only in the second molars (RE 4/1036, p < 0.001; first molars RE 14/974, p = 0.49). Among the affected teeth, RP was relatively more common in the second molars (Holm-adjusted p = 0.025), whereas the excess of RE in the first molars did not survive correction for multiple testing (Holm-adjusted p = 0.26).

Conclusion: The presence of extra roots in mandibular molars within the Turkish population is a key variation for access cavity preparation in endodontics. The different distributions of these roots between the first and second molars emphasize the need for a thorough pre-treatment radiographic assessment.