Evidence suggests that treating periodontal disease can improve glycemic control

Periodontal disease makes glycemic control more difficult in patients with type 2 diabetes, said George W. Taylor, DrPH, DMD,associate professor of dentistry, School of Dentistry and Public Health at the University of Michigan, Ann Arbor.

In addition, evidence suggests that treating periodontal disease may lead to improved glycemic control; possibly prevent,delay, or reduce the severity of the complications of diabetes; and possibly prevent the development of diabetes.

"Periodontal infection contributes to the total inflammatory burden," said Dr. Taylor. Tissue damage from infection bygram-negative anaerobes can promote inflammatory cytokine over-expression and entrance of inflammatory cytokines into thecirculation. These inflammatory cytokines can have effects on insulin resistance.

Treating periodontal infection has been shown to have a beneficial influence on systemic inflammation; namely, reductions inlevels of C-reactive protein, interleukin-6, and tumor necrosis factor-alpha, and improvement in endothelial function.

In analyzing data from the third National Health and Nutrition Examination Surveys (NHANES III; 1988-1994), an associationwas discovered between severe periodontitis and insulin resistance (as measured by HOMA) in individuals without diabetes atbaseline. Those individuals with periodontal disease had 3.7 times the odds of insulin resistance as those withoutperiodontal disease. For this analysis, periodontitis was defined as at least one site with 5 mm or more of attachment lossand significant gingival bleeding at teeth with 5 or more mm of attachment loss.

Observational studies show an increase in hemoglobin A1c levels and poorer glycemic control with severe periodontitis. Amonga subset of NHANES III participants aged 45 years or older, 59% with severe periodontal disease had poor glycemic controlcompared with 39% without severe periodontal disease. In a multivariate model, severe periodontitis was associated with anodds ratio of 4.9 for poor glycemic control.

In therapeutic studies, nonsurgical periodontal therapy has been associated with trends toward improved glycemic control. Ameta-analysis of 10 studies revealed a 0.4% improvement in HbA1c levels with nonsurgical therapy, and a 0.7% improvement inA1c levels among those with type 2 diabetes.

A small pilot trial at the National Institutes of Health was conducted in which 46 patients with periodontal disease wererandomized to one of three groups: periodontal treatment plus treatment with doxycycline, periodontal treatment plustreatment with metronidazole, or delayed periodontal treatment (cleaning not below the level of the gingival). After 15months of follow-up, reductions in A1c levels ranged from 0.4% (doxycycline group) to 0.8% (delayed treatment group). Theaverage reduction in A1c levels was 0.67%. On the basis of this study, a multicenter randomized controlled clinical trial isbeing planned, said Dr. Taylor.

In studies of periodontal disease and the complications of diabetes, associations between severe periodontal disease and anincreased risk for cardiorenal mortality, macroalbuminuria, and end-stage renal disease have been found.