Abstract:
Objective To explore the risk factors between the extraction of the mandibular third molars (M3M) and the injury of the inferior alveolar nerve (IAN), and to construct a preoperative risk evaluation model for M3M extraction.
Methods From January 2023 to December 2024, a total of 724 M3Ms extracted at the Hospital of Stomatology, Sun Yat-sen University were retrospectively enrolled in this study. The subjects were divided into the IAN injury group and the non-IAN injury group based on whether IAN injury occurred after M3M extraction. Chi-square test was used to compare the clinical characteristic indicators between the two groups. Univariate and multivariate logistic regression analyses were conducted to explore the risk factors between M3M extraction and IAN injury.
Results Chi-square test showed statistically significant differences between the two groups, including age, gender, M3M impaction depth, M3M root curvature, relative position of the inferior alveolar canal (IAC), IAC morphology, and IAN exposure. Univariate logistic regression analysis indicated that these indicators were independent risk factors for IAN injury. Multivariate logistic regression analysis revealed that patients aged 30 or above had a higher risk of IAN injury than those under 30 (OR = 2.250) ; female patients had a higher risk of IAN injury than male patients (OR = 3.223) ; the deeper the M3M impaction, the higher the risk of IAN injury (OR = 2.977) ; curved roots had a higher risk of IAN injury than non-curved roots (OR = 3.875) ; the risk of IAN injury was lower when the nerve was located on the lingual side of M3M than on the buccal side (OR = 0.263) ; the closer the root was to the IAC, the higher the risk of IAN injury (OR = 1.942) ; and IAN exposure after M3M extraction increased the risk of IAN injury (OR = 5.566). Based on the predictive values of multivariate logistic regression analysis, a ROC curve was drawn, with an AUC of 0.861, a sensitivity of 0.843, and a specificity of 0.789.
Conclusions Female patients over 30 years old and the dumbbell-shaped IAC located on the lingual side of the low-positioned impacted M3M should be regarded as high-risk cases for IAN injury. If M3M root curvature and IAN exposure after extraction are also found, the risk of IAN injury would be even higher after M3M extraction.
Key words:
Molar, third,
Tooth extraction,
Alveolar nerve, inferior,
Injuries,
Risk factors
Xiangqi Liu, Jiashun Wu, Xueting Luo, Meixia Tian, Xin Yang, Shijun Kuang. Analysis of the risk factors between mandibular third molar extraction and inferior alveolar nerve injury[J]. Chinese Journal of Stomatological Research(Electronic Edition), 2026, 20(02): 119-125.