Long-term effect of non-surgical periodontal treatment on glycaemic control in patients with diabetes with periodontitis: a systematic review and meta-analysis of randomized controlled trials

Abstract Aim This study aimed to determine whether non-surgical periodontal therapy (NSPT), with or without antimicrobial adjuvant therapy, in diabetic patients with periodontitis was effective in significantly reducing glycated haemoglobin (HbA1c) over six months compared to no active treatment. Methods MEDLINE, EMBASE and CENTRAL were searched to identify randomized controlled trials with a follow-up period of at least 6 months. The risk of bias was investigated by the Cochrane intention-to-treat risk of bias assessment tool (ROB 2) with 6-month HbA1C as the primary outcome. A random-effects meta-analysis was conducted to obtain the overall effect of non-surgical periodontal therapy on HbA1c levels. A subgroup analysis according to the type of adjuvant therapy was conducted. Results The literature search yielded 1848 studies, of which 10 were finally retained. An overall low risk of bias was found in four studies. The pooled mean difference of HbA1c between the intervention and control groups at 6 months and 9 months for non-surgical periodontal therapy was − 0.11% (95% CI: -0.31 to 0.09) and − 0.21 (95% CI: -0.72 to 0.29) respectively. Compared to the control group, periodontal parameters (plaque index, bleeding on probing, probing pockets depth, and clinical attachment levels) as well as levels of selected inflammation markers (C-reactive protein and tumor necrosis factor-α) were significantly (P-value < 0.05) improved in the intervention group. Conclusion NSPT with or without adjuvant contributed to a modest, although not statistically significant, improvement in glycaemic control at 6 and 9 months in diabetic patients with periodontitis.