Nonsurgical periodontal therapy doesn't appear to help glycemic control

Patients with type 2 diabetes and significant chronic periodontitis derived no glycemic benefit from nonsurgical periodontal therapy, according to a new study.

Researchers performed a 6-month, single-masked, multicenter randomized clinical study, the Diabetes and Periodontal Therapy Trial, to test whether hemoglobin A1c (HbA1c) levels would improve with nonsurgical periodontal therapy in patients who had type 2 diabetes and moderate to advanced chronic periodontitis. Eligible patients had HbA1c levels between 7% and 9% and were enrolled from diabetes clinics, dental clinics and communities that were affiliated with 5 academic medical centers.

Patients assigned to the treatment group underwent scaling and root planing and received oral rinse with chlorhexidine at baseline; they also received supportive periodontal therapy at 3 and 6 months. Patients assigned to the control group received no periodontitis treatment. The study's primary outcome measure was the between-group difference in change in HbA1c level at 6 months, while secondary outcome measures were changes in periodontal measures (including probing pocket depths, clinical attachment loss, bleeding on probing, gingival index, and Homeostasis Model Assessment score) and fasting glucose level. The study results were published in the Dec. 18, 2013, Journal of the American Medical Association.

Two hundred fifty-seven patients were assigned to the treatment group and 257 patients were assigned to the control group between November 2009 and March 2012. The data and safety monitoring board recommended that trial enrollment be stopped early due to futility. Two hundred forty-four patients (47%) took oral hypoglycemic agents only, 80 (16%) took only insulin, 179 (35%) took both, and 11 (2%) didn't take any diabetes medications. Overall, at 6 months, mean HbA1c levels increased 0.17% in the treatment group compared with 0.11% in the control group, and the 2 groups did not differ significantly in a linear regression model that was adjusted for clinical site (mean difference, −0.05%; P=0.55). The treatment group did see statistically significant improvement in probing depth, clinical attachment loss, bleeding on probing and gingival index at 6 months compared with the control group. No serious adverse events related to the study were noted in either group.

The authors noted that they did not use antibiotics or surgical treatment for periodontitis and that their results may not apply to patients with HbA1c levels other than 7% to 9%, among other limitations. However, they concluded that while nonsurgical periodontal treatment appeared to improve chronic periodontitis in diabetic patients, it did not help glycemic control. “These findings do not support the use of nonsurgical periodontal treatment in patients with diabetes for the purpose of lowering levels of HbA1c,” they wrote.