The systemic impact of non-surgical treatment of peri-implantitis with or without adjunctive systemic metronidazole: Secondary analysis of a randomized clinical trial.

Objectives: The aim of this study was to evaluate the systemic effect of non-surgical peri-implantitis treatment (NSPIT) with or without the administration of systemic metronidazole.

Methods: In this secondary analysis from a previously published clinical trial (NCT03564301), peri-implantitis patients were randomized into two groups: test, receiving NSPIT plus 500 mg of oral systemic metronidazole three times a day for 7 days (n = 10); and control group, receiving NSPIT plus placebo (n = 11). Serum samples were obtained at baseline, 3 and 6 months after therapy to determine levels of inflammatory biomarkers, lipid fractions and complete blood counts.

Results: Both treatment modalities produced improvements in clinical and radiographic parameters. After 6 months from NSPIT, a substantial reduction in C-reactive protein (6.9 mg/dL; 95% CI: 3.7 to 9.9, p < .001) and low-density lipoprotein cholesterol (21.8 mg/dL; 95% CI: -6.9 to 50.5, p = .013) as well as a modest increase in neutrophils counts (0.4 × 10³/μL; 95% CI: -0.4 to 1.1, p = .010) was observed in the control group while the test group showed a significant reduction of TNF-α (110.1; 95% CI: 38.9 to 181.4, p = .004).

Conclusions: NSPIT showed a short-term beneficial systemic effect regardless of adjunctive use of systemic metronidazole.