Factors influencing inferior alveolar nerve injury after extraction of mandibular third molar.

Background: This study sought toexplore the manifestations of clinical symptoms and identify the risk factors linked to inferior alveolar nerve injury (IANI) in the context of mandibular third molar extraction.

Material and methods: In this study, 172 patients admitted to our hospital for mandibular third molar extraction from June 2021 to December 2022 were selected for the study, and the clinical data of the participants were retrospectively analyzed, and the risk factors of IANI associated with mandibular third molar extraction were analyzed by uni/multi-factor logisitic regression.

Results: Noticeable distinctions were noted between the groups with and without injuries in relation to age, time of surgery, number of broken roots, angle of blockage, CEJ (cementoenamel junction) distance, curved roots of the molar, clarity of the upper and lower walls of the nerve canal, and Pell & Gregory classification. Logistic regression analysis showed that age, time of surgery, number of broken roots, angle of blockage (40°-70°), CEJ distance (10-12 mm, >12 mm), and curved roots of the molar were independent risk factors for IANI. Multi-factor logistic regression analysis further confirmed that age, number of broken roots, angle of blockage (40°-70°), CEJ distance (10-12 mm, >12 mm), and curved roots of the molar were associated with IANI.

Conclusions: Alveolar nerve injury manifests as hyperalgesia or absence of sensation, numbness and abnormal pain in the lower lip. Factors influencing IANI associated with mandibular third molar extraction were age, number of broken roots, angle of blockage (40°-70°), CEJ distance (10-12 mm, >12 mm), and curved roots of the molar.