The prevalence of three-rooted permanent mandibular first molars in the population of Slovenia
A mandibular first molar usually has a mesial and a distal root; however, a distolingually-located third root is occasionally present. The three-rooted mandibular first molar (TMFM) plays a significant role in anthropology and forensic medicine because its prevalence varies significantly among ethnic groups. The aim was to determine the prevalence of TMFMs in a population of Slovenia by using periapical radiographs. A total of 1145 mandibular first molars were evaluated using periapical radiographs that were collected from dental records of 1000 patients (470 males and 530 females). The radiographs were evaluated using a viewing box and a magnifying glass; 95% confidence intervals (CI) for the prevalence of TMFMs in the population were estimated using Wald’s method. Fisher’s exact test was applied to examine any statistically significant difference between left and right teeth and between male and female patients. The prevalence of TMFMs was 2.36% (1.61%-3.42%, 95% CI). No statistically significant differences were detected with respect to sex (p = 0.1235) or the side of occurrence (p = 0.2505). The observed prevalence of TMFMs is in the upper half of the range for ethnic European populations.