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.