研究口腔颌面部锥形束CT（CBCT）检查结合牙体分割微创拔牙技术在下颌阻生第三磨牙（IMTM）拔除中的临床应用。

选取2018年1月至2019年5月四川省攀枝花市中心医院诊断为IMTM的97例（155颗）拔牙患者为研究对象。术前CBCT明确IMTM与周围重要组织的关系，术中采用转角高速涡轮机夹持长臂裂钻分割牙体，以微创的方式分块拔除IMTM。记录拔牙时间、患者满意度、术中及术后并发症等指标。采用t检验比较男、女间拔牙时间的差异，采用方差分析比较不同阻生牙类型及不同年龄段组间拔牙时间的差异。

CBCT结果显示67.7%（105/155）的下颌管位于IMTM根尖的颊侧、22.6%根尖下方、9.7%舌侧，其中24.5%<1 mm；24颗（15.5%，24/155）IMTM根尖区舌侧骨板缺如，56颗牙（36.1%，56/155）<1 mm。IMTM以近中、垂直及水平向阻生最为常见，平均拔牙时间分别是（24.3±1.1）min，（15.6±1.2）min，（29.7±1.8）min，差异有统计学意义（F=23.85，P<0.001）；术中8颗牙（5.2%，8/155）下颌管暴露，无1例舌侧骨板损伤致牙根移位。术后3例少量出血，1例发生干槽症，无1例发生下唇麻木，患者满意度在95.5%以上。

CBCT应作为IMTM拔除前常规的影像学检查手段。高速涡轮机牙体分割微创拔牙技术适用于各类IMTM拔除，具有创伤小、临床效率高、并发症少、患者满意度高等优点。

To study the clinical application of cone beam computed tomography (CBCT) combined with minimally invasive extraction technology in the extraction of impacted mandible third molars (IMTM).

Ninety-seven patients (155 teeth) diagnosed with IMTM at Panzhihua Central Hospital from January 2018 to May 2019 were selected as study subjects. Before operation, CBCT was taken to clarify the relationship between IMTM and surrounding important tissues. During the operation, the teeth were segmented with a long arm split drill with high-speed turbine and IMTM was extracted in a minimally invasive way. The extraction time, patient satisfaction, and intraoperative and postoperative complications were recorded. The difference of extraction time between males and females was compared by the t-test, and the difference of extraction time between different age groups was compared by ANOVA.

CBCT showed that 67.7% (105/155) of mandibular canals were located in the buccal side, 22.6% under the root tip, and 9.7% in the lingual side of IMTM, of which 24.5% was less than 1 mm. There were 24 (15.5%, 24/155) IMTM apical regions with lingual bone plate missing and 56 teeth (36.1%, 56/155) less than 1 mm. Angular, vertical, and horizontal impactions were the most common types of IMTM. The average extraction time was (24.3±1.1) min, (15.6±1.2) min, (29.7±1.8) min, respectively (F=23.85, P<0.001). Eight teeth (5.2%, 8/155) were exposed to mandibular canal during the operation, and there was no root displacement caused by lingual bone plate injury. There were three cases of bleeding and one case of dry socket. There was no case of numbness of the lower lip. The rate of patient satisfaction was more than 95.5%.

CBCT should be used as a routine imaging examination before IMTM extraction. High speed turbine assisted minimally invasive extraction technology is suitable for all kinds of IMTM extraction. It has the advantages of small trauma, high clinical efficiency, few complications, and high patient satisfaction.