Periodontal therapy and systemic inflammation in type 2 diabetes mellitus: a meta-analysis

The aim of this systematic review was to assess the effect of periodontal therapy (PT) on serum levels of inflammatory markers in people with type 2 diabetes mellitus (T2DM).

A literature search was carried out using MEDLINE via Pubmed, EMBASE, LILACS and Cochrane Central Register of Controlled Trials (CENTRAL) databases. Randomized-controlled trials (RCTs) and controlled clinical trials (CCTs) evaluating the effect of PT on systemic inflammatory markers were deemed eligible. Case series (CS), reports and pilot trials were excluded. Study quality was assessed using the Cochrane Collaboration's risk assessment tool. Meta-analysis was carried out using random effect methods.

The search strategy identified 3,164 potential studies of which 61 were assessed for eligibility and 9 (6 RCTs and 3 CCTs) were included in this systematic review. Three RCTs were classified by the authors as being at low risk of bias and three were "unclear" and classified as uncertain risk of bias. All CCTs were considered to be at a high risk of bias. The meta-analysis showed a statistically significant mean difference (MD) for TNF- α (-1.33 pg/ml, 95% CI: -2.10; -0.56, p<0.001) and CRP (-1.28 mg/l, 95% CI: -2.07; - 0.48, p<0.001) favoring periodontal intervention versus control.

The results of this meta-analysis support the hypothesis that PT reduces serum levels of TNF- α and CRP in T2DM individuals. The decrease of inflammatory burden has important implications for metabolic control and can, in part, explain the mechanisms linking periodontitis and increased risk for complications in people with T2DM.