Influence of age and vertical facial type on the location of the mandibular foramen.

PURPOSE: A successful inferior alveolar nerve block anesthesia necessitates knowledge of the exact location of the mandibular foramen. The aim of this study was to determine whether the location of the mandibular foramen is related to the age or the vertical facial morphology of the patient. METHODS: Lateral cephalometric radiographs from 145 patients (average age 10.4 years; range 6.3 to 14.6 years) were collected. The position of the mandibular foramen was investigated both antero-posteriorely and vertically in relation to the occlusal plane. Pearson's correlation and multiple regression analysis were performed between the variables under study. RESULTS: The mandibular foramen was horizontally located at 60 percent of the ramus width from its anterior border. The vertical distance of the mandibular foramen from the occlusal plane was significantly correlated to all examined variables, especially to the patient's age (r=0.69, P<0.001), the inter-maxillary angle (r=-0.60, P<0.001), and the lower facial anterior soft tissue ratio (r=-0.76, P<0.001). Multiple regression analysis explained more than 70 percent of the variation of the vertical position of the mandibular foramen. CONCLUSIONS: Taking into consideration the age and the facial morphology of the patient may help better locate the mandibular foramen, which is a prerequisite for a successful and safe inferior alveolar nerve block.