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Evid Based Dent. 2009;10(1):20-1. doi: 10.1038/sj.ebd.6400633.

Periodontal treatment could improve glycaemic control in diabetic patients.

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Department of Health Policy and Health Services Research, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, USA.



Medline, Pascal, Embase, LILACS, the Cochrane Library, International Association of Dental Research Abstracts and Current Contents databases were searched and, in addition, a manual search was made of the bibliography of all pertinent articles. Unpublished articles were researched by contacting authors. No restrictions on language or type of article were applied in the literature search.


Two investigators reviewed the full texts independently. To be included in the meta-analysis, studies had to be original interventional studies, conducted on a human population in which subjects had both diabetes and periodontitis, and provided a numerical value for HbA1c (glycosylated haemoglobin level). Review articles and meta-analyses were excluded and only the most recent reference of a multiple publication was included.


The two reviewers independently extracted data using a standardised data-extraction grid. Data from the controlled studies were combined to estimate the pooled differential variation of HbA1c between control and treatment groups, using the inverse-variance method. Both fixed and random-effects models were used to calculate the overall standardised mean difference (SMD). Statistical homogeneity across the studies was tested by Cochran's Q test. Potential publication bias was tested using the rank-correlation test for funnel-plot asymmetry.


Twenty-five studies, involving 976 subjects in total, were included in the present systematic review. Of these, nine studies, comprising 485 patients, were controlled trials and were included in the meta-analysis. The SMD in HbA1c with the treatment of periodontal disease was 0.46 [95% confidence interval (CI), 0.11-0.82]. These findings suggest that periodontal treatment could lead to a significant 0.79% (95% CI, 0.19-1.40) reduction in HbA1c level.


The present meta-analysis represents the best information available to date that addresses this issue, and suggests that periodontal treatment could improve glycaemic control. Nevertheless, these results should be viewed with caution because of a lack of robustness and deficiencies in the design of some of the studies included. A randomised controlled trial (RCT) with sufficient statistical power would help to confirm the results of this meta-analysis.


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