Long-term Effect of Periodontal Treatment on Glycemic Control: a Meta-analysis

Methods: A literature search (until February 2009) was carried out using two databases (Medline and The Cochrane Library) with language restriction to English. Selection of publications was based on: i) original investigations, ii) controlled periodontal intervention studies, where the diabetic control group received no periodontal treatment and iii) study duration of ≥3 months.

Results: Screening of the initially 639 identified studies and reference checking resulted in 4 suitable papers. A total of 322 patients were included in this analysis, with periodontitis as predictor and the actual change in hemoglobin A1c (ΔHbA1c) as the outcome. All studies described a research population of type 2 diabetic patients in which glycemic control improved after periodontal therapy compared with the control group (Range ΔHbA1c: from -0.16% to -1.17%). The studies in a meta-analysis demonstrated a weighted mean difference (WMD) of ΔHbA1c before and after therapy of -0.56% (95% CI -0.09% to -1.03%) (P=0.02) favoring periodontal therapy in type 2 diabetes patients. However, this improvement in %HbA1c showed limited robustness as evidenced by a strong tendency to heterogeneity (59.5%; P=0.06).

Conclusion: The present meta-analysis suggests that periodontal treatment leads to an improvement of glycemic control in type 2 diabetes patients for at least 3 months and that periodontitis may be causally associated with diabetes mellitus type 2. However, more and homogeneous evidence is needed.