Foramen mandibulae as an indicator of successful conduction anesthesia.

Comparative measurements were made of 144 orthopantomographs in 50 patients with successful and 94 patients with unsuccessful inferior alveolar nerve block anesthesia. The results show that the bony lingula is prominent in 28.5% of all patients, or in 56.0% of those with unsuccessful anesthesia. The variables mandibular notch vs. mandibular foramen (MN-MF) and the anterior ramus ridge vs. mandibular foramen (ARR-MF) show greater distances in the group of patients with successful anesthesia, while the variables of posterior ramus ridge vs. mandibular foramen (PRR-MF) and mandibular angle vs. mandibular foramen (MA-MF) were greater in the group of patients with unsuccessful anesthesia (p > 0.05). It is concluded that the variability in position of the mandibular foramen among others may be responsible for an occasional failure of inferior alveolar nerve block.