State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu City, 610041, China.
Department of Stomatology, The First Affiliated Hospital of Soochow University, Soochow City, 215006, China.
J Craniomaxillofac Surg. 2024 Oct;52(10):1164-1171. doi: 10.1016/j.jcms.2024.08.009. Epub 2024 Aug 20.
This study aimed to evaluate the relationship between the precise three-dimensional location of the third molar (M3) and mandibular angle fracture (MAF) patterns and to assess the effect of the volume ratio occupied by M3 in the mandibular angle on fracture patterns. The location of M3 was assessed in 218 patients with MAF using computed tomography reconstruction. The bone volume of the mandibular angle and the bone volume occupied by M3 were measured to calculate the volume ratio of M3 to the mandibular angle (M3/MA). MAF patterns were categorized into simple fracture (Type I), displaced fracture (Type II), and comminuted fracture (Type III) based on fracture severity. The results showed that the location of M3 significantly influenced MAF patterns (vertical position: P = .001; horizontal position: P = .002; angulation: P = .027, respectively) and the volume ratio of M3/MA was significantly higher for Type III fracture than Types I and II (P < .001). Regression analysis showed that the horizontal position and angulation of M3 and the volume ratio of M3/MA were the main predictors for comminuted MAF. A larger volume ratio (odds ratio [OR], 1.201; 95% confidence interval [CI], 1.037-1.391; P < .014), Class III position (OR, 7.978; 95% CI, 1.275-49.910; P < .026), and horizontal angulation (OR, 7.212; 95% CI, 1.028-50.581; P < .047) of the M3 were more prone to comminuted MAF than simple fracture. Our findings indicate that the location of M3 significantly affects MAF patterns, and that M3 may weaken the mandibular angle by occupying more bone space, thereby increasing the risk of a comminuted fracture.
本研究旨在评估第三磨牙（M3）的精确三维位置与下颌角骨折（MAF）类型之间的关系，并评估 M3 在下颌角中所占体积比率对骨折类型的影响。通过计算机断层扫描（CT）重建评估 218 例 MAF 患者的 M3 位置。测量下颌角的骨量和 M3 占据的骨量，以计算 M3 与下颌角的体积比（M3/MA）。根据骨折严重程度，将 MAF 类型分为单纯骨折（I 型）、移位骨折（II 型）和粉碎性骨折（III 型）。结果表明，M3 的位置显著影响 MAF 类型（垂直位置：P=0.001；水平位置：P=0.002；角度：P=0.027），且 M3/MA 的体积比在 III 型骨折中显著高于 I 型和 II 型（P<0.001）。回归分析表明，M3 的水平位置和角度以及 M3/MA 的体积比是粉碎性 MAF 的主要预测因素。较大的体积比（比值比[OR]，1.201；95%置信区间[CI]，1.037-1.391；P<0.014）、III 类位置（OR，7.978；95%CI，1.275-49.910；P<0.026）和水平角度（OR，7.212；95%CI，1.028-50.581；P<0.047）的 M3 更易发生粉碎性 MAF 而不是单纯骨折。我们的研究结果表明，M3 的位置显著影响 MAF 类型，M3 通过占据更多的骨空间可能削弱下颌角，从而增加粉碎性骨折的风险。
