Influence of CGF Combined with Bio-Oss Bone Powder on Alveolar Bone Increment and Pink Esthetic Score in Patients Undergoing Implant Restoration for Lower Molar Defects

OBJECTIVE: The distal changes of mandibular second molars (M2M) after the extraction of mandibular third molars (M3M) are manifested as deep periodontal pocket, attachment loss and bone defects. The purpose of this study was to evaluate the influence of concentrated growth factor (CGF) and Bio-Oss bone powder on alveolar bone increment and pink esthetic score (PES) in patients with lower molar defects undergoing implant restoration. METHODS: From January 2022 to June 2025, 168 patients with M2M distal bone defects after M3M extraction were classified into Bio-Oss group (93 cases) and CGF+Bio-Oss group (Bio-Oss bone powder and CGF mixed at a 1:1 ratio, 75 cases) by retrospective method. In all 168 patients the implant was placed in the mandibular molar region simultaneously with M3M extraction and grafting of the M2M distal bone defect at the same surgical visit (immediate implant placement); no delayed placement and no site treated by socket preservation alone were included, so that all 168 patients were evaluable for implant success. The primary clinical outcomes were implant success rate and alveolar bone increment at 6 months after surgery, and the secondary outcomes encompassed vascular endothelial growth factor (VEGF) and bone morphogenetic protein-2 (BMP-2) in gingival crevicular fluid before surgery and at 2 weeks and 3 months after surgery, clinical attachment loss (CAL), periodontal probing depth (PD) and PES at 3 months and 6 months after surgery as well as adverse reactions. RESULTS: At 6 months after surgery, the implant success was achieved in 75 cases (100%) in the CGF+Bio-Oss group and in 89 cases (95.70%) in the Bio-Oss group. One case failed due to infection, and three cases failed due to periodontal inflammation. There was no statistically significant difference in implant success rate between the two groups (P=0.191). Alveolar bone increment was (3.37±0.75) mm in the CGF+Bio-Oss group and (2.60±0.74) mm in the Bio-Oss group, and alveolar bone increment was higher in the CGF+Bio-Oss group (P<0.001). Repeated measures analysis of variance (ANOVA) results revealed that the group x time interaction effects of VEGF and BMP-2 were statistically significant in both groups (F=6.877, 5.649, P=0.010, 0.019), with 95%CI of the between-group difference in estimated marginal means (Bio-Oss group minus CGF+Bio-Oss group, averaged across the three time points) being -3.091 to -1.799 for VEGF and -3.942 to -2.768 for BMP-2 respectively. Furthermore, the CGF+Bio-Oss group exhibited higher VEGF and BMP-2 at 2 weeks and 3 months after surgery (P=0.012, 0.021, 0.020, 0.004). CAL and PD were lower while PES was higher in the CGF+Bio-Oss group at 3 months and 6 months after surgery (all P<0.001). No obvious difference was found in the occurrence of adverse reactions between both groups (P=0.881). CONCLUSIONS: For patients with M2M distal bone defects after M3M extraction, the combined use of CGF and Bio-Oss bone powder was associated with a greater alveolar bone increment and showed better periodontal clinical indicators and pink esthetic scores than Bio-Oss bone powder alone, without an increase in adverse reactions. As this was a retrospective observational study, these findings indicate association rather than a causal effect and require confirmation in prospective controlled trials.