Harnessing the Therapeutic Potential of Locally Delivered 1% Metformin Gel for Modulation of Clinical and Inflammatory Parameters in Peri-Implantitis Disease: A Prospective Clinical Evaluation

Peri-implantitis is a chronic inflammatory disease that poses a significant challenge to human health due to persistent microbial biofilm accumulation and limited peri-implant tissue regeneration, adversely affecting oral wellbeing and implant survival. Adjunctive pharmacological interventions in implant medicine, such as locally delivered metformin, may enhance therapeutic outcomes by attenuating inflammation and promoting peri-implant tissue repair, with potential relevance to public health. This study aimed to evaluate the clinical and biochemical effects of 1% metformin gel as an adjunct to mechanical debridement in peri-implantitis management. In this prospective clinical study, 54 systemically healthy participants (25-60 years) with peri-implantitis were randomly assigned to control (mechanical debridement alone, n = 27) or test (mechanical debridement + 1% metformin gel, n = 27) groups. Plaque Index (PI), Gingival Index (GI), Probing Pocket Depth (PPD), Clinical Attachment Level (CAL), and interleukin-6 (IL-6) levels in peri-implant crevicular fluid were assessed at baseline and 6 months. Data were analyzed using paired and independent t-tests. Baseline values were comparable between groups (P > 0.05). At 6 months, the test group showed significantly lower PI (0.49 vs. 1.37, P < 0.001), GI (0.51 vs. 1.40, P < 0.001), PPD (3.02 mm vs. 4.17 mm, P < 0.001), CAL (3.22 mm vs. 4.34 mm, P < 0.001), and IL-6 levels (8.13 pg/mL vs. 19.23 pg/mL, P < 0.001) compared with the control. Both groups improved from baseline (P < 0.001), with markedly greater reductions in the test group. Local application of 1% metformin gel adjunctive to mechanical debridement significantly enhances clinical and anti-inflammatory outcomes in peri-implantitis, highlighting its potential as a safe, cost-effective, and bioactive therapeutic strategy.