Does periodontal treatment have an impact on metabolic control and systemic inflammation in patients with type 2 diabetes?

Design Systematic review and meta-analysis.Data sources A search of two databases, Medline and CENTRAL, was undertaken, limited to articles published in English from the oldest records until 10 July 2018.Study selection Participants included patients diagnosed with type 2 diabetes and periodontitis, with HbA1c and C-reactive protein (CRP) measurements at baseline. The intervention was surgical or non-surgical periodontal therapy. The control was no periodontal treatment, supra-gingival scaling or oral hygiene instruction. The outcome was HbA1c and CRP measurements three months later.Data extraction and synthesis Two independent reviewers assessed articles initially by title and abstract, before reviewing full texts of relevant studies. Disagreements were resolved through discussion or a third reviewer. Data extraction included definition of periodontal disease, periodontal intervention and average changes in HbA1c and CRP. Risk of bias was assessed using the Cochrane Collaboration tool. Two meta-analyses were performed to determine the effects of periodontal intervention on HbA1c and CRP.Results Out of 402 potential studies, nine randomised controlled trials were included. Six studies had no periodontal treatment reported in the control arm, whereas oral hygiene instruction or supra-gingival scaling was described in three studies. The intervention in all studies was non-surgical periodontal treatment, but one also involved surgical debridement. No heterogeneity was detected using the Cochrane Q test or I2 statistic. The majority of studies were deemed to be at high risk of performance bias due to a lack of blinding of participants. The results of the meta-analyses indicated a significant reduction in percentage of HbA1c (difference in means = 0.56, 95% CI [0.36-0.75], p <0.00001) and in CRP levels (difference in means = 1.89, 95% CI [1.70-2.98], p <0.00001).Conclusions Periodontal treatment improves metabolic control as well as reduces systemic inflammation in patients with type 2 diabetes.