Analysis of the Relation Between the Area of Mandibular Third Molar and Lingual Nerve Injury: Comparison of Japanese Anatomical Considerations and Three‐Point Measurement Using Cone Beam Computed Tomography

ABSTRACT Aim Lingual nerve injury (LNI) is a known complication of mandibular third molars. However, its relationship with factors such as mandibular morphology or the surgical technique remains unclear. This study aimed to assess the preoperative risk of LNI by evaluating mandibular morphology using cone beam computed tomography data. Methods The LNI group ( n = 41) and the control group ( n = 410) comprised patients who underwent third molar extraction. Three reference points (A, B, and C) were defined around each mandibular third molar to calculate the surrounding area, which was compared between the two groups. The etiology of LNI in the affected group was also investigated. The data were analyzed using statistical methods. Results The LNI cohort ( n = 41) was mainly female (35/41), mean age 31.7 years; all injuries followed mandibular third molar extraction. Twenty patients received conservative therapy and 21 nerve repair, and most index extractions were by general dentists. LNI molars were mostly vertical (18) or horizontal (10). Lingual cortical bone was usually thin (30/41) or defective (4/41), with high agreement (κ = 0.95). Versus controls, vertical and horizontal LNI cases had significantly shorter BC width, and vertical cases showed a smaller ABC area. Conclusion The results suggest that LNI associated with mandibular third molar extraction is related to the buccal width of the mandible. Preoperative assessment of tooth position, particularly the inclination of tooth axes, using x‐ray imaging is crucial and provides a valuable reference for the safe removal of mandibular third molars.