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 × 10 3 /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.