Correlation of mandibular premolar roots with mental foramen in periapical radiographs

Background: The location of the mental foramen and its relationship with the roots of mandibular premolars is essential in surgeries and endodontic treatments, premolar extractions, and placing implants in the region. The current study aims to investigate the frequency of variations in the correlation of mandibular premolars with the mental foramen of the patients referred to the Birjand Dental School. Methods: During this study, 328 periapical radiographs of the patients referring to the oral & maxillofacial radiology (OMFR) department were evaluated. The horizontal and vertical relationship of the mental foramen to the mandibular premolars was assessed and noted in the checklist. Results: Horizontally, 47.2% of mental foramen were in line with the vertical axis of second premolars. After that, the most frequent horizontal location of mental foramen was between the roots of the first and second premolars, with a prevalence of 37.1%. Vertically, the most frequent location of mental foramen was reported below the line connecting the root apexes of the mandibular premolars, with a prevalence of 78.7%. The horizontal and vertical location of mental foramen did not significantly differ between genders or age groups (P>0.05). Conclusions: In this local population, the most frequent horizontal location of mental foramen is along with the vertical axis of the mandibular second premolar and, after that, between the roots of the second and first premolars. The most prevalent vertical location of mental foramen is below the line connecting the apexes of the premolars.