Many have suggested a two-way relationship between periodontitis and  diabetes mellitus. Poor glycaemic control is associated with an increase risk of periodontal disease and in 2010 a Cochrane review  (Simpson et al) estimated a 0.4% reduction of HbA1c associated with periodontal treatment.  At that time Simpson et al noted that there were only a small number of studies available and these lacked the power to detect a significant effect.  With the publication of additional studies the aim of this review was to evaluate whether non-surgical periodontal treatment can reduce the HbA1c% level in type 2 diabetic patients.

The Cochrane CENTRAL, Medline and Embase databases were searched together with the reference lists of identified publications. Only randomised controlled trial were included if the study population was type 2 diabetic patients (≥16 years old) diagnosed with periodontitis, and compared HbA1c% change with or without non-surgical periodontal treatment for at least three months of the study duration. Four reviewers conducted study selection independently and study quality was assessed on random sequence generation; allocation concealment; addressing incomplete outcome data; blinding; and intention-to-treat analysis.

• 6 studies involving a total of 442 patients were included.
• A significant difference in HbA1c (%) change was evident between the treatment and control groups with an effect size of -0.41% (95% CI: -0.73% to -0.09%). (P = 0.037).
• There was significant heterogeneity between studies .
• Evidence of publication bias was found with small  studies with findings favouring the intervention of interest were more likely to be published in journals, and vice versa.

The authors concluded

This meta-analysis found there was a small beneficial effect of non-surgical periodontal treatment in glycaemic control. However, the effect of adjunctive antibiotic usage in this association remained inconclusive to date.

Comment

While a small number of randomised controlled trials have been published since the 2010 Cochrane review the size and the quality of the trial is still low as noted by the authors. The overall change in HbA1c found is very similar to the Cochrane review of – 0.40% (95% CI fixed effect -0.78% to -0.01%).   Only 2 out of the 3 papers included in the Cochrane review were included in this current review.   As the number and quality of  studies available to answer this question is low as the Cochrane reviewers suggested;-

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.

Links

Liew, A., Punnanithinont, N., Lee, Y.-C. and Yang, J. (2013), Effect of non-surgical periodontal treatment on HbA1c: a meta-analysis of randomized controlled trials. Australian Dental Journal, 58: 350–357. doi: 10.1111/adj.12091

Simpson TC, Needleman I, Wild SH, Moles DR, Mills EJ. Treatment of periodontal disease for glycaemic control in people with diabetes. Cochrane Database of Systematic Reviews 2010, Issue 5. Art. No.: CD004714. DOI: 10.1002/14651858.CD004714.pub2.