下颌阻生第三磨牙拔除难度预判

目的：制定直观准确的下颌阻生第三磨牙拔除难度评估方案。方法：选取病例300例，根据牙齿阻生方向、骨及邻牙阻挡程度、牙根变异以及年龄性别设定各参考因素计算分值，由不同年资医生单独完成难度评估，再由一名医生实施手术，观察难度预判准确度。结果：术前评估准确度可达95％～98％，量化的难度预判分值与拔牙时间成显著正相关关系。结论：通过分解分析阻生智齿冠根阻力及个体影响因素，可更有效的判断其拔除难度。

Difficulty Assessment before Extraction of Impacted Mandibular Third Molar

Objective： To make a more clear and precise protocol for difficulty assessment before extraction of the im- pacted mandibular third molar. Methods： A total of 300 patients were involved. Factors associated with the tooth impaction were evaluated by grading scores, including tooth position, crown obstacle from overlying bone and adjacent molar, root variation, age and gender of the patients. Difficulty of the extraction was assessed by three doctors with different profession- al seniorities. Then the tooth was extracted all by one doctor. The accuracy of the prediction was evaluated. Results ： The pre -operational difficulty assessment could get a high accordance of 95% -98% with the actual situation. A significant positive correlation was found between the numerical value of the impacted molar and the actual time need for the extrac- tion. Conclusion： The separated analysis of the obstructive forces on the crown and root, associated with related personal factors, could help in predicating how difficult it will be to extract the mandibular third molar.