Treatment Outcome of Surgical Protocols for Peri-Implantitis: A Retrospective Cohort Study in a Specialised University Centre

Aim: To explore the treatment outcome of surgical peri-implantitis protocols in a university-based setting. Materials and Methods: Four-hundred and six implants in 223 patients were surgically treated by four trained surgeons using open-flap debridement (OFD, 37 implants), implantoplasty (Impl, 39 implants), reconstructive surgery (Rec, 241 implants) or a combined approach (Comb, 89 implants). Treatment success after 1 year (maximum probing depth (max PD) ≤ 5 mm, bleeding on probing (BOP) at ≤ 1 site and no suppuration) was the primary outcome. Logistic regression was used to explore associations between patient-/implant-related factors, treatment modalities and treatment success, implant loss and surgical retreatment. Results: Treatment was successful in 54.7% of implants after 1 year: OFD 62.5%, Impl 58.3%, Rec 55.4%, Comb 48.3%, with no significant group differences. Over a mean follow-up of 30.80 ± 19.62 months, 40 implants (9.9%) were lost and 38 (9.4%) required surgical retreatment. In exploratory multivariable analyses, systemic antibiotic use (pre-operative: OR = 3.54, p = 0.04; pre- and post-operative: OR = 4.49, p = 0.02) and surgeon experience (OR = 0.12, p = 0.003) showed associations with treatment success. Molar site (OR = 3.21, p = 0.03), antibiotic (pre- and post-operative: OR = 3.13, p = 0.02) and baseline suppuration (OR = 4.51, p = 0.002) were associated with implant loss. Surgical retreatment was associated with overdenture (OR = 3.59, p = 0.003) and max PD at baseline (OR = 1.30, p = 0.001). Conclusions: Surgical peri-implantitis outcome was associated with systemic antibiotic, surgeon, molar site, overdenture, baseline suppuration and PD.