Influence of acellular dermal matrix on peri-implant soft tissue phenotype and marginal bone loss following immediate implant placement in the anterior maxilla: a randomized controlled clinical trial

Abstract Background Immediate implant placement in the anterior maxilla is associated with dimensional changes in both hard and soft tissues, which may compromise esthetic outcomes. This randomized controlled clinical trial aimed to evaluate the effect of acellular dermal matrix (ADM) on peri-implant soft tissue phenotype and marginal bone loss following immediate implant placement. Methods Patients requiring replacement of non-restorable maxillary anterior teeth were randomly allocated into two equal groups. The control group received high-density polytetrafluoroethylene (d-PTFE) membrane coverage, while the study group received ADM. Clinical parameters, including keratinized mucosal width (KMW), mucosal thickness (MT), and supracrestal tissue height (STH), were assessed at 6 months. Plaque accumulation and bleeding were monitored using modified sulcus bleeding index (mSBI) and plaque index (PI) at 1, 2, and 3 months after prosthetic loading. Implant stability was measured at placement and after 6 months. Radiographic outcomes, including marginal bone loss (MBL) and bone width (BW), were assessed using fused CBCT images at baseline and 6 months. In the study group, ADM was inserted into facial and palatal pouches. The primary outcome was peri-implant soft-tissue phenotype at 6 months, assessed by KMW, MT, and STH. Results Thirty-three patients were assessed for eligibility, and sixteen patients were randomly allocated into two equal groups ( n = 8 per group). All implants survived without complications during follow-up. At 6 months, the study group demonstrated significantly greater keratinized mucosal width (5.9 ± 1.0 vs. 3.3 ± 0.6 mm, p < 0.001), mucosal thickness (1.8 ± 0.3 vs. 0.8 ± 0.3 mm, p < 0.001), and supracrestal tissue height (1.2 ± 0.3 vs. 0.8 ± 0.3 mm, p = 0.012) than the control group. No significant differences between groups were observed in mSBI or PI. Implant stability increased significantly in both groups, with higher values in the ADM group at 6 months ( p = 0.010). The study group also exhibited significantly less marginal bone loss, whereas horizontal bone width reduction was comparable between groups. Conclusion ADM was associated with improved peri-implant soft tissue phenotype and reduced marginal bone loss compared with d-PTFE membranes while maintaining comparable peri-implant health. These findings support the potential use of ADM during immediate implant placement in the anterior maxilla. Trial registration The study was retrospectively registered and listed on www.clinicaltrials.gov with registration number (NCT07573020) on 07-05-2026.