Bilateral absence of mental foramen – a rare variation

The mental foramen is described in literature as an oval or circular opening on the anterior surface of the mandible, usually below the apex of the first or second premolar or between the first and second premolars. The inferior alveolar nerve and artery enter the mandibular foramen and after traveling through the body, exit at the mental foramen as the mental nerve and vessels. These nerves provide sensory innervation to the lower teeth, lip and a part of lower face [1]. The mental foramen has also been characterized as a highly suitable model to study bone remodeling activity in the presence of different spatial osteo-neuro-vascular components. Recent advancements in orthodentistry have increased the possibility of invasive procedures in the mental region. The position of the mental foramen may vary according to race and ethnicity [2–4]. The direction of the opening of the mental foramen is outward and upward in a posterior orientation [5]. The identification and actual location of this foramen is important in clinical dentistry during nerve block and the evaluation of the morphology and maturity of the human mandible. Variations of the mental foramen are often encountered, ranging from difference in modal location [2–4] or presence of accessory foramina [6] or even complete absence in some rare cases [7–9]. However, these variations are often insufficiently described in most anatomy textbooks. Their accurate identification by a prior 3D-CT scan may reduce the incidence of Tabinda HASAN [1] Mahmood FAUZI [2] Deeba HASAN [3]