Position of the mandibular foramen in adult male Tanzania mandibles.

Failure of the inferior alveolar nerve block anesthesia is common in various dental operations. Anatomical variations of the location of the inferior alveolar nerve as it enters the mandibular foramen have been implicated as a main cause of these anesthesia failures. The aim of this work was to determine the location of the mandibular foramen in relation to the occlusal plane at the level of mandibular first molar and second premolar--often used as landmarks during the blocking procedure--and to different landmarks on the ramus of the mandible. The study was performed using mandibles from adult black male Tanzanians aged 30-45 years. Measurements were accomplished using two-digit electronic Vernier calipers. The distances were determined from the center of the mandibular foramen to the different reference points. The mandibular foramen was above the occlusal plane at the M1 and PM2 reference points in all the mandibles studied. It was also located about 20 mm and 12 mm from the anterior and posterior borders of the ramus respectively. There was no significant difference between the left and right side in any of the measurements. These results indicate that during anesthetic or other clinical procedures, the clinician can precisely determine the position of neurovascular bundle of the inferior alveolar nerve above the occlusal plane.