[A retrospective study on changes in buccal bone thickness following immediate implant placement after dental trauma...

Objective: To evaluate the effects of flap and flapless surgical approaches on changes in buccal bone thickness around implants in patients undergoing immediate implant placement after dental trauma under a fiber-reinforced composite (FRC) splint-supported immediate provisionalization protocol, and to provide clinical evidence for surgical decision-making in the esthetic zone following dental trauma. Methods: This retrospective cohort study included patients who presented to the Department of General Dentistry, Shanghai Ninth People's Hospital between December 2022 and December 2025 with traumatic maxillary anterior tooth loss requiring immediate implant placement and who had completed definitive prosthetic rehabilitation. According to whether a flap was elevated during surgery, patients were allocated to either a flap group or a flapless group. All implants were provisionally restored immediately after surgery using a fiber-reinforced resin splint combined with natural teeth or resin crowns. Cone-beam computed tomography (CBCT) scans obtained preoperatively, immediately after surgery, and at 4 months postoperatively were used to assess preoperative buccal bone plate thickness and postoperative changes in buccal bone thickness around the implants in both groups. Results: No statistically significant differences in buccal bone thickness were observed between the flap and flapless groups at any measurement level immediately after surgery or at 4 months postoperatively (all P0.05). At 4 months postoperatively, buccal bone thickness at most measurement levels in both groups was significantly reduced compared with the immediate postoperative values (all P0.05), except at 12 mm apical to the implant platform in the flapless group, where no significant bone resorption was detected (all P0.05). No significant differences were found between the two groups in buccal bone thickness changes at any measurement level at 4 months postoperatively (all P0.05). Conclusions: For immediate implant placement following dental trauma in the esthetic zone, when strict case selection and a FRC splint-supported immediate provisionalization protocol are applied, flap and flapless surgical approaches do not appear to differ significantly in their ability to maintain short-term buccal hard tissue stability.