Cross-sectional and prospective epidemiological studies have shown that periodontitis increases the risk of poor glycaemic control in patients with diabetes mellitus as well as diabetes complications and associated morbidity.
The evidence for an association between diabetes and periodontitis is as follows:
- Plausibility – type-2 diabetes is preceded by systemic inflammation, leading to reduced pancreatic β-cell function, apoptosis and insulin resistance. Increasing evidence supports elevated systemic inflammation (acute-phase and oxidative stress biomarkers), resulting from the entry of periodontal organisms and their virulence factors into the circulation, thus providing biologically plausible mechanisms underpinning the adverse impact of periodontitis upon diabetes and its complications.
- Epidemiological data – consistent and robust evidence is available which demonstrates that severe periodontitis adversely affects glycaemic control in diabetes and glycaemia in non-diabetes patients. In addition, in patients with diabetes, there is a direct and dose-dependent relationship between periodontitis severity and diabetes complications. Emerging evidence indicates an increased risk for diabetes onset in patients with severe periodontitis.
- Intervention studies – some randomised clinical trials demonstrate that mechanical periodontal therapy associates with a moderate reduction in HbA1C at three months.16 A more recent, large scale multi-centre randomised clinical trial, however, concluded that non-surgical periodontal treatment of participants with type 2 diabetes and chronic periodontitis did not demonstrate a benefit for measures of glycaemic control.17