Prevalence of 3- and 4-rooted first and second mandibular molars in the Israeli population.

Introduction: Three-rooted mandibular molars are 1 of the anatomic variations of mandibular molars. The location of the additional root is distolingual (radix entomolaris) or mesiobuccal (radix paramolaris). The purpose of this retrospective study was to assess the prevalence of 3- and 4-rooted mandibular first and second molars in the Israeli population and to classify them according to dimension, curvature, and location of separation from the main root.

Methods: A total of 1020 Israel patients' cone-beam computed tomographic scans were screened and evaluated. The incidence of 3- and 4-rooted first and second mandibular molars were recorded and analyzed. One thousand four hundred sixty-five mandibular second molars and 1,229 mandibular first molars were evaluated.

Results: The overall incidence of patients with 3-rooted mandibular first and second molars was 2.6% and 1.78%, respectively. The bilateral incidence of 3-rooted mandibular first and second molars was 26%. The incidence of 4-rooted mandibular second molar was 0.55%. No significant difference was found regarding sex or side of occurrence.

Conclusions: The occurrence of 3-rooted mandibular first molars in the Israeli population was rare, but clinicians should be aware of the special characteristic of this anatomic variation to modify accordingly the form of pulp chamber opening and choose appropriate instrumentation.