Topographical relationship between positions of lingual foramina and attachment of mylohyoid muscle in mental region

Lingual foramina can be observed between the lingual aspects of the mandible in humans. A sublingual artery is thought to exist in sublingual space and a submental artery in submaxillary space, which pierce the mandible through lingual foramina. During surgery for oral implant placement between apices of the mental foramen, it is important to determine the existence and positioning of lingual foramina. The purpose of this study was to investigate the positions of lingual foramina in relation to the mylohyoid muscle and vertical position of the mylohyoid line using cone-beam computed tomography (CBCT) images. We examined 20 formalin-perfused cadavers. The mylohyoid muscle was dissected and marked with a silicone tube, then CBCT images were obtained to evaluate the relationship of that muscle with lingual foramina. We observed 37 lingual foramina in the 20 cadavers. As for vertical positioning, 16 lingual foramina were found in sublingual space, while in horizontal positioning, 6 were found in the anterior region of sublingual space. The ratio of vertical distance from the inferior margin to the mylohyoid line and mental spine was lower in the anterior region as compared to the posterior region. In this study, lingual foramina were found to commonly exist in sublingual space above the mylohyoid muscle and pierce the mesial side. For evaluation of the vertical position of the mylohyoid line, it is better to use the stable mental spine rather than the alveolar process.