Effect of nonsurgical periodontal treatment on glycosylated hemoglobin in diabetic patients: a systematic review

This review was designed to determine whether non-surgical periodontal treatment is able to reduce serum glycosylated hemoglobin (HbA1c) levels in patients with diabetes mellitus (DM). Several previous reports showed that scaling and root planning (SRP) improve periodontal status in patients with DM, but whether it also improves metabolic control of the disease is unclear. A systematic review was conducted according to the recommendations of the Cochrane Collaboration and PRISMA. A literature search was conducted in October 2012 using three libraries (Cochrane, Web of Knowledge, and Scopus) and the keywords "periodontal disease'' and "diabetes mellitus.'' Only 21 of the articles met the inclusion criteria for this review. A total of 1,454 patients were thus included in this study to evaluate whether periodontal treatment improved serum HbA1c levels. Both the methodological quality and the risk of bias of each study were taken into account using the Jadad scale. Only ten of the included studies had an acceptable-good score of 3-5. Fourteen of the studies reported a significant decrease in serum HbA1c levels (p < 0.05) after periodontal treatment. The remaining seven studies failed to find a significant decrease in serum HbA1c. The findings of this review suggest that the published literature is insufficient and inconclusive to clearly support periodontal treatment as a means to improve serum HbA1c levels in patients with type 1 DM. It also demonstrates the need for homogeneous studies, with larger samples and longer follow-up periods, to properly address this question.