Locally delivered metformin as adjunct to scaling and root planing in the treatment of periodontal defects: A systematic review and meta-analysis.

This study aimed to evaluate the efficacy of metformin as an adjunct to scaling and root planing (SRP) in the treatment of chronic periodontitis. Electronic searches were conducted in databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials and Cochrane Oral Health Group Trials Register databases) up to August 2017. Randomized clinical trials with data in comparison between adjunctive locally delivered metformin use to SRP and placebo in each group and a follow-up period of at least 6 months, were included. Primary outcomes included clinical attachment level, while secondary outcomes were bone defect (BD) fill and reduction in probing depth. The weighted mean differences (WMD) of outcomes and 95% confidence intervals (CI) for each variable were calculated using the random effects model. Five clinical studies were included in the qualitative synthesis and 3 studies were included for meta-analysis. All the included studies showed significant BD fill, probing depth reduction and clinical attachment level gain with adjunctive locally delivered metformin compared to SRP alone. Considering the effects of adjunctive metformin as compared to SRP, a high degree of heterogeneity for BD fill (Q value = 7.03, P = .02, I2  = 71.55%) was noticed among both the groups. Meta-analysis showed a statistically significant clinical attachment level gain (WMD = -2.83, 95% CI = -3.32 to -2.34, P < .001), BD fill (WMD = -2.96, 95% CI = -3.99 to -1.93, P < .001) and probing depth reduction (WMD = -3.11, 95% CI = -3.63 to -2.59, P < .001) for SRP + metformin treatment vs SRP. Adjunctive use of metformin delivery in periodontal treatment appears to be effective in BD fill, reducing probing depth and gain in clinical attachment level. Further multicentered randomized clinical trials are warranted in future to prove additional benefits of metformin as an adjunct to SRP in the treatment of chronic periodontitis.