Evaluation of Position and Symmetry of Mental Foramen on Digital Panoramic Radiographs: A Retrospective Study

Background: The mental foramen is an important anatomical landmark located on the anterolateral surface of the mandible, and it transfers the mental nerve and vessels. Knowledge of the position of the mental foramen is important both when administering regional anaesthesia and performing periapical surgery in the mental region of the mandible. Aim: The aim of this study was to determine the position and symmetry of the mental foramen on a digital orthopantomogram (OPG) among the Nalgonda population. Materials and Methods: A total of 400 digital OPGs taken by the Rotograph evo OPG machine of both genders were analysed retrospectively. The position of the mental foramen was recorded according to criteria given by Wei Cheong Ngeow and Yosuf Yuzawati. The symmetrical or asymmetrical position of the mental foramen was also recorded. Results: The most common position in the current study for the right side was position 4 (n = 202; 50.5%) followed by position 3 (n = 102; 25.5%), position 5 (n = 82; 20.5%), position 2 (n = 8; 2%), position 1 (n = 4; 1%) and the least common was position 6 (n = 2; 0.5%) and the most common position of mental foramen for left side was position 4 (200;50%) followed by position 3 (n = 132; 33%) , position 5 (n = 60; 15%), position 1 and 2 (n = 4; 1%) and the least common was position 6 (n = 0; 0%). The mental foramen was symmetrical in 250 patients (62.5%) and asymmetrical in 150 patients (37.5%). For the symmetrically placed mental foramina, the most common location was position 4 (n = 126; 50.4%) followed by position 3 (n = 76; 30.4%), position 5 (n = 42; 16.8), position 6 (n = 4; 1.6%), position 2 (n = 2; 0.8%), position 1 (n = 0; 0%). Conclusion: In the present study, it was found that the most common position of the mental foramen in the given population in both males and females was below the second premolar, followed by between two premolars. It was symmetrical in 62.5% of OPG’s. The current study was limited to evaluating the position and symmetry of the mental foramen relative to mandibular teeth in a small sample of the Nalgonda population in Telangana state using digital panoramic radiographs. In further studies, utilizing a larger sample size for evaluation of the mental foramen using advanced imaging modalities would be required for a more precise identification of the mental foramen.