Treating periodontal disease may improve metabolic control in diabetics

The Cochrane Oral Health Group's Trials Register, The Cochrane Central Register of Controlled Trials (CENTRAL), Medline, EMBASE, CINAHL, ZETOC, ISIWeb of Knowledge and LILACS databases were searched together with hand searches of the journals Annals of Periodontology (1996 to 2003) and Periodontology 2000 (1993 to 2003).There were no language restrictions.

This review included randomised controlled trials of people with type 1 or 2 diabetes mellitus (DM) with a diagnosis of periodontitis. Suitable interventions included mechanical periodontal therapy with or without adjunctives and oral hygiene education.

The titles and abstracts of all identified papers were examined by two review authors' independently. All included trials were assessed for risk of bias. Data were collated in evidence tables, grouped according to research design and assessed for possible meta-analysis on the basis of homogeneity of main characteristics.

Seven studies were included and three studies had results pooled into a meta-analysis. The effect for the mean percentage difference in HbA1c for scaling/root planing and oral hygiene (+/- antibiotic therapy) versus no treatment/usual treatment after 3/4 months was -0.40% (95% confidence interval (CI) fixed effect -0.78% to -0.01%), representing a statistically significant reduction in HbA1c (P = 0.04) for scaling/root planing. One study was assessed as being at low risk of bias with the other two at moderate to high risk of bias. A subgroup analysis examined studies without adjunctive antibiotics -0.80% (one study: 95% CI -1.73% to 0.13%; P = 0.09), with adjunctive antibiotics in the test group -0.36% (one study: 95% CI -0.83% to 0.11%; P = 0.14), and with antibiotics in both test and control groups after 3/4 months -0.15% (one study: 95% CI -1.04% to 0.74%; P = 0.74).

There is some evidence of improvement in metabolic control in people with diabetes, after treating periodontal disease. There are few studies available and individually these lacked the power to detect a significant effect. Most of the participants in the study had poorly controlled type 2 DM and there was little data from randomised trials on the effects on people with type 1 DM. Improving periodontal health is an important objective in itself. However, in order to understand the potential of this treatment to improve glycaemic control among people with diabetes, larger, carefully conducted and reported studies are needed.