Peri-implantitis is a destructive inflammatory disease that compromises implant survival, oral health, and patient well-being. Metformin, a widely used medicine, possesses anti-inflammatory and osteogenic properties that may enhance regenerative outcomes in peri-implant therapy. To evaluate the clinical and radiographic outcomes of a metformin-loaded collagen membrane as an adjunct to reconstructive surgical therapy for peri-implantitis. Fifty-two systemically healthy participants with peri-implantitis-associated infrabony defects were enrolled in this prospective one-year clinical study. Group A (n=26) received xenogeneic bone grafting with a conventional collagen membrane, while Group B (n=26) received xenogeneic bone grafting with a metformin-loaded collagen membrane. Clinical parameters (PI, GI, PPD, and CAL) and radiographic bone level (BL) were assessed at baseline and one year. Both groups demonstrated significant improvements in all clinical and radiographic parameters after one year (p < 0.001). However, Group B showed significantly greater reductions in PI, GI, PPD, CAL, and BL compared with Group A (p < 0.001), indicating enhanced inflammation control and peri-implant tissue regeneration. The adjunctive use of a metformin-loaded collagen membrane resulted in superior clinical and radiographic outcomes compared with a conventional collagen membrane. Local metformin delivery may represent a promising regenerative strategy for peri-implantitis management, thereby supporting oral health and patient wellbeing.
