Abstract: PURPOSE: To investigate the effect of autogenous tooth bone powder combined with concentrated growth factors (CGF) in the repair of distal bone defects in the second molar after impacted mandibular third molar extraction. METHODS: A total of 25 patients with distal bone defect of second molar after bilateral mandibular impacted third molar extraction were selected in the First Affiliated Hospital of Xinjiang Medical University from June 2023 to June 2024. A bilateral controlled experiment was conducted, with one side as the experimental group (n=25) and the other side as the control group (n=25). The experimental group received treatment with autogenous tooth powder combined with CGF, while the control group received CGF treatment alone. Postoperative probing depth(PD), clinical attachment loss(CAL), osseous defect depth(ODD), bone mineral density, operative time, Postoperative Symptom Severity Scale(PoSSe), adjacent tooth hypersensitivity, postoperative infection, and numbness of lower lip were compared between the two groups. SPSS 26.0 software package was used for data analysis. RESULTS: At 3 and 6 months postoperatively, the PD and CAL in both groups were significantly lower than those at 2 weeks postoperatively (P<0.001); the reduction rates of PD and CAL in the experimental group were significantly higher than those in the control group at 6 months postoperatively (P<0.001); the reduction amount of ODD in the experimental group was significantly higher than that in the control group at 3 and 6 months postoperatively (P<0.001). There were significant differences in bone density between the experimental group and the control group at 3 and 6 months postoperatively. The operation time in the experimental group was longer than that in the control group, with a statistically significant difference. The postoperative PoSSe scores for speech, appearance, and pain showed significant different between the two groups (P<0.05). The incidence of distal tooth sensitivity of the second molar in the control group was significantly higher than that in the experimental group(P<0.05). CONCLUSIONS: Autogenous tooth bone powder combined with CGF can effectively promote the recovery of distal bone defects in the second molar, improve the periodontal condition of the distal second molar, and has high clinical application value. CGF alone can also improve the depth of distal bone defects in the second molar, but the recovery of the height of the bone defect is not obvious, and the long-term effect is not good.

Key words: Mandibular third molar, Mandibular second molar, Bone defect, Bone regeneration, Autogenous tooth powder, Concentrated growth factors