Flapless immediate implant placement with or without xenogeneic bone substitute grafting: a 30-month randomized controlled trial

Immediate implant placement is associated with remodeling of the peri-implant hard and soft tissues. Buccal gap grafting has been proposed to reduce dimensional changes; however, its long-term clinical benefits remain uncertain. This study aimed to evaluate the 30-month clinical, radiographic, and esthetic outcomes of buccal gap grafting following flapless immediate implant placement. This study represents the 30-month follow-up of a previously conducted randomized controlled clinical trial. Nineteen patients receiving 24 implants were allocated to flapless immediate implant placement with buccal gap grafting using a xenogeneic bone substitute (test group) or without grafting (control group). The primary outcome was peri-implant marginal bone level change at 30 months. Secondary outcomes included peri-implant clinical parameters, early buccal bone dimensional changes assessed by cone-beam computed tomography (CBCT) at 4 months, and esthetic outcomes evaluated using the Pink Esthetic Score (PES) and White Esthetic Score (WES). Implant-level outcomes were analyzed using generalized estimating equations (GEE) to account for clustering of implants within patients. Implant survival was 100% at the 30-month follow-up. Total marginal bone level loss was 0.08 ± 0.53 mm in the test group and 0.53 ± 0.50 mm in the control group, with an estimated between-group difference of 0.45 mm (95% CI, 0.06–0.84; P = 0.025). No significant between-group differences were observed in peri-implant clinical parameters, early buccal bone dimensional changes, or esthetic outcomes assessed using the PES and WES. Within the limitations of this exploratory long-term follow-up study, buccal gap grafting was associated with reduced peri-implant marginal bone loss after flapless immediate implant placement. However, the clinical relevance of this difference remains uncertain, and no significant benefits were observed for peri-implant soft tissue health or esthetic outcomes. Larger randomized clinical trials with appropriate statistical methods and long-term three-dimensional radiographic assessment are needed to confirm these findings. Iranian Registry of Clinical Trials (IRCT), IRCT201606188898N3. Registered on 9 September 2016. This study represents a long-term follow-up of a previously conducted randomized controlled clinical trial.