Background: Uncontrolled diabetes is a known risk factor for periodontal disease, and evidence suggests that periodontal disease may have an adverse effect on glycemic control.
Clinical question: In patients with Type 1 or Type 2 diabetes, does periodontal therapy, compared with no active treatment or usual care, improve glycemic control?
Summary of methods and results: Seven databases were searched for randomized controlled trials (RCTs), and hand searching of journals and reference lists was performed. Two authors independently screened titles and abstracts, extracted data, and assessed risk of bias, with a third author arbitrating disagreements. Thirty-five RCTs were identified. These studies either compared nonsurgical periodontal therapy, defined as scaling and root planing (SRP) or mechanical therapy, with usual care or no active treatment, or compared different types of nonsurgical periodontal therapy. Low-quality evidence indicates that SRP reduces mean glycosylated hemoglobin (HbA1c) by 0.29 percentage points (95% confidence interval [CI]: 0.48% to 0.10% lower) at 3 to 4 months, and 0.02 percentage points (95% CI: 0.20% lower to 0.16% higher) at 6 months. The addition of antimicrobial therapy did not provide added benefit to SRP alone, with 0.00 percentage points change in HbA1c at 3 to 4 months (95% CI: 0.22% lower to 0.22% higher), and 0.04 percentage points lower HbA1c at 6 months (95% CI: 0.41% lower to 0.32% higher).
Critical appraisal: This was a well-conducted systematic review. However, pooling of data when comparing SRP with SRP + antimicrobial was questionable due to clinical heterogeneity (differing antimicrobial therapies). The overall evidence is of low quality. The magnitude of effect of SRP in reducing HbA1c is minor, short-term, and has unclear clinical relevance.
Practical implications: Because of concerns with the low quality of evidence and uncertain magnitude of effect, the results of this systematic review should be interpreted with caution. It remains prudent to manage periodontal disease in all patients, especially those with risk factors such as diabetes, as a recent American Dental Association (ADA) systematic review and guideline suggests that SRP is an effective management strategy for periodontal disease. However, it is uncertain if nonsurgical periodontal treatment will have a sustained and significant impact on glycemic control in patients with diabetes.