Three-dimensional anatomic analysis of mandibular foramen with mandibular anatomic landmarks for inferior alveolar nerve block anesthesia

Abstract

We sought to standardize 3-dimensional anatomic positioning of the mandibular foramen (MnF) for inferior alveolar nerve block anesthesia. Three-dimensional mandibular computerized tomography (CT) images were reconstructed from data for 49 patients aged 8-16 years (growth group) and 59 patients aged 18-25 years (adult group). To measure MnF position, we defined 5,6 as the superior contact point between the mandibular first molar and second premolar and 5,6 MnFP as the point on the MnF plane intersecting 5,6 at a right angle. The MnF plane passed through the MnF and parallel to the occlusal plane. In the growth group, the distance from the MnF to the anterior ramus increased with age, as did distance from the gonion to MnF. Measurements correlated significantly with age in the growth group. Needle insertion at an obtuse angle in the MnF plane from the contralateral first molar is appropriate for inferior alveolar nerve block anesthesia.