Botulinum toxin type A (BoNT-A) has been applied successfully to treat chronic migraine, dystonia, spasticity and temporomandubular disorders(TMDs) as well as frontal wrinkle and glabella wrinkle. Recently it has been reported that BoNT-A, reversibly blocks presynaptic acetylcholine release, also inhibits the release of substance P, CGRP(calcitonin gene related peptide) and glutamate related to peripheral sensitization and neurogenic inflammation in sensory nerve, In this study we reviewed animal nerve injury model such as rat and rabbit and identify the analgesic effect and mechanism of nerve injury pain after dental treatment.