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Can Periodontal Therapy Improve Diabetes Control?

Jan 2, 2014

In a new trial, researchers find that normal periodontal therapy doesn’t improve glycemic control for patients with type 2 diabetes. However, our Advisory Board member, Maria Ryan, DDS, PH.D, has a somewhat different take on these results….

“Although periodontal treatment improved clinical measures of periodontitis in patients with diabetes, the findings do not support the use of nonsurgical periodontal treatment for the purpose of lowering levels of HbA1c,” the authors write.


The study population included 514 adults aged 35 and older with type 2 diabetes and HbA1c levels of 7% to 9%. All had moderate to advanced chronic periodontitis, defined as clinical attachment loss and probing depth of at least 5 mm in 2 or more quadrants of the mouth. None had received periodontal treatment in the prior 6 months.

Nearly half (47%) of patients were taking oral glucose-lowering agents alone for their diabetes, 16% were taking insulin alone, and 35% were taking both. Just 2% were taking no medications.

The 257 patients randomized to periodontal treatment received at least 160 minutes of scaling and root planing using curettes and ultrasonic instruments under local anesthesia at baseline. They were then given oral hygiene instructions along with a toothbrush, toothpaste, dental floss, and chlorhexidine gluconate rinse, to be used twice daily for 2 weeks. One-hour scaling/planing sessions were provided at 3 and 6 months, along with further oral-hygiene instructions. The control group (257) received only the oral-hygiene instructions at baseline, 3, and 6 months.

HbA1c did not change significantly between baseline and 3 or 6 months in the treatment or control groups, and there were no differences between the 2 groups at either time point in the intent-to-treat or per-protocol analysis (P = .55 and P = .50, respectively, at 6 months).

Similarly, no differences were seen in fasting glucose levels or insulin sensitivity.

However, periodontal clinical parameters were significantly improved in the treatment group compared with controls. At 6 months, probing depth improved by 0.4 mm in the treatment group compared with just 0.1 mm in controls. Mean bleeding with probing decreased by 19% with treatment vs just 5.9% for controls, and clinical attachment loss and gingival index measures also improved more with treatment vs controls (all P < .001).

There was also no significant difference between the treatment and control groups in proportions with diabetes-medication changes during the study (55% vs 60%).

As expected following scaling and root planing, the treatment group experienced more soreness, tenderness, or pain than controls (40% vs 28%, P = .004) and thermal sensitivity (32% vs 18%, P < .001).

Several previous small trials had suggested there may be a glycemic benefit from periodontal treatment, with the theory being that chronic inflammation associated with periodontitis might contribute to worsened glycemic control. Indeed, a recent meta-analysis from Engebretson’s group suggested modest HbA1c reduction following periodontal therapy.

However, previous trials have generally been small and have not accounted for changes in medication, as was done in the current trial. It’s possible that periodontal inflammation and infection don’t influence glycemic control, Engebretson and colleagues note.

Despite the negative findings, they say, “periodontal therapy may be considered in patients for reasons other than glycemic control, such as for benefits to tooth retention and masticatory function.”

The results were published December 18 in the Journal of the American Medical Association (JAMA) by Steven P. Engebretson, DMD, from the department of periodontology and implant dentistry of New York University, New York, and colleagues.

Reply from Maria Ryan DDS, Ph.D, Diabetes In Control Advisory Board Member:

I am aware of this study and a number of other recently conducted NIDCR sponsored studies looking into the impact of SRP as a monotherapy to address periodontal disease and its impact on A1c, on pre-term delivery, on endothelial cell function, etc. The results of these studies support what I have been lecturing on for years. Minimal periodontal intervention is inadequate in high risk populations who will require use of host modulatory agents and/or antimicrobials and perhaps more aggressive procedures such as surgery to adequately address their periodontal condition and resolve the inflammation.