To compare the effectiveness and prognosis of traditional tooth extraction and coronation surgery in the treatment of high-risk mandibular impacted third molars, so as to provide clinical reference for the application of coronation surgery.

A total of 300 patients in the Department of Oral & Maxillofacial Surgery, Hospital of Stomatology, Sun Yat-sen University, from June 2021 to June 2022, were recruited. All patients were examined with CBCT for the root position of the mandibular impacted third molars. Based on the patients′ decision on treatment plans, 244 patients underwent traditional tooth extraction surgery and 56 patients underwent coronation surgery. In the traditional tooth extraction group, the whole molars were extracted by pieces, while in the coronation group, only the crowns of molars were removed. The incidence of nerve injury, bleeding and dry socket was compared between the two groups. The prognosis of coronation surgery was also evaluated.

The incidence of inferior alveolar nerve injury in the conventional group (6.6%) was statistically higher than that in the coronation group (0%, χ² = 3.879, P = 0.049). The incidence of lingual nerve injury, postoperative bleeding and dry socket in the conventional group was comparable with that in the coronation group (χ²_{lingual nerve injury} = 0.230, P_{lingual nerve injury} = 0.631; χ²_{postoperative bleeding} = 0.206, P_{postoperative bleeding} = 0.650; χ²_{dry socket syndrome} = 0.090, P _{dry socket syndrome} = 0.763). In the coronal surgery group, there was only one case that a second surgery was required to remove the root due to root eruption, indicating that the incidence of such late complications was low, but persisted.

Coronation surgery had a lower incidence of postoperative complications in the treatment of impacted mandibular third molars, which would be a safer option for the extraction of wisdom teeth.