Marginal soft tissue recession after lateral guided bone regeneration at implant site: A long-term study with at least 5 years of loading

Background/aim: This study evaluated marginal soft tissue recession at implants with simultaneous lateral guided bone regeneration (GBR), at least five years after prosthetic loading. Material and methods: Patients treated with GBR at the time of implant placement and adherent to supportive periodontal therapy (SPT) program with at least 5 years of follow-up were re-examined in 5 clinical centers. At the last follow-up, clinical and radiographic data on peri-implant hard and soft tissue were collected. Multilevel analysis considering center, patient, and implant (brand, length, diameter, position) was performed. Results: A total of 96 patients and 195 augmented implants were included. The mean duration of SPT was 8.3 ± 3.1 years, while mean recall frequency was 4.5 ± 1.3 months. Sixty-five (33%) implants received soft tissue graft before prosthetic delivery. Twenty-one (11%) implants developed biological complications during the follow-up. No implant failure was reported. Mean difference in bone levels (ΔBL) was −0.7 ± 0.9 mm, while mean difference in keratinized tissue (ΔKT) was −0.4 ± 0.9 mm. Eighty-five (44%) implants showed recession (REC) of soft tissue margin (mean 0.6 ± 0.8 mm). The presence of REC was associated with use of non-resorbable membrane (p <.0001) and wider implant diameter (p =.0305), while use of soft tissue graft significantly predicted higher stability of peri-implant mucosal margin (p =.0003). Conclusion: Peri-implant mucosal recession is a common feature 5 years after lateral GBR. The risk of recession may be reduced using GBR with resorbable membranes, small diameter implants, and soft tissue grafting before prosthetic treatment.