Removal of mandibular third molars is one of the most common operations in oral surgery. Hypoesthesia of the lower lip occurring after the extraction of third molars is a serious complication, requiring a prolonged time for recovery. In this study, we investigated factors potentially affecting the incidence of hypoesthesia.
A total of 781 mandibular third molars extracted at our clinic in 2002 were examined. There were 17 cases (2.2%) of hypoesthesia of the lower lip. There was no relation of gender, difficulty of extraction, or the skill of the operator to the incidence of hypoesthesia. In contrast, the incidence of hypoesthesia strongly correlated with age and the root position of mandibular third molars with respect to the mandibular canal.
Eleven of the 17 cases of hypoesthesia (64.7%) resolved within 1 month, and 16 of the 17 cases (94.1%) resolved within 6 months. The patients who had hypoesthesia for more than 1 monthwere significantly older than those who recovered from hypoesthesia within 1 month and were all female.
These results might be useful when informing patients about potential complications of tooth extraction.
