Does Adjunctive Homecare Sub-Gingival Irrigation Improve the Systemic Inflammatory–Glycaemic Axis? A Randomized Controlled Analysis of C-Reactive Protein and Glycated Haemoglobin in Type 2 Diabetic Patients with Chronic Periodontitis

Background: Type 2 diabetes mellitus (T2DM) and chronic periodontitis are linked by a shared inflammatory pathophysiology in which the systemic dissemination of periodontal pro-inflammatory mediators elevates the acute-phase response and aggravates insulin resistance. C-reactive protein (CRP) is a sensitive marker of this systemic inflammatory burden, whereas glycated haemoglobin (HbA1c) integrates glycaemic control over the preceding two to three months. Whether adjunctive homecare sub-gingival water irrigation, added to non-surgical periodontal therapy (NSPT), produces measurable benefit along this systemic inflammatory–glycaemic axis, over and above conventional oral hygiene, remains poorly defined. Objective: To determine whether adjunctive homecare sub-gingival irrigation, compared with conventional brushing and flossing after NSPT, produces a differential effect on the systemic inflammatory marker CRP and on glycaemic control (HbA1c) in adults with T2DM and chronic periodontitis, and to examine whether the systemic response tracks the resolution of periodontal inflammation. Methods: A single-blind, parallel-group randomized controlled trial enrolled 140 patients with T2DM (baseline HbA1c below 7%) and generalized chronic periodontitis at the Department of Periodontology and Oral Implantology, Yamuna Institute of Dental Sciences and Research, Yamuna Nagar. After Phase I therapy, participants were randomized equally to homecare sub-gingival irrigation plus brushing (Group 1) or brushing and flossing alone (Group 2). Serum CRP (latex agglutination) and HbA1c (liquid chromatography) were measured at baseline and six months; periodontal inflammatory parameters were recorded in parallel. Between-group differences were analysed with independent-sample t-tests and within-group change with paired testing, significance at p<0.05. Results: CRP fell substantially in both groups but significantly more with irrigation, from 17.06±2.42 mg/L to 6.96±1.21 mg/L in Group 1 versus 18.27±2.38 mg/L to 10.17±1.90 mg/L in Group 2; the six-month value (p<0.001) and the magnitude of reduction (9.10 vs 8.10 mg/L, p=0.048) both favoured Group 1. HbA1c declined modestly and almost identically in both arms (Group 1: 6.69% to 6.44%; Group 2: 6.76% to 6.52%), with no significant inter-group difference at six months (p=0.192) or in magnitude of change (p=0.182). The greater systemic anti-inflammatory response in Group 1 paralleled its greater resolution of periodontal inflammation, whereas the glycaemic response did not diverge between arms. Conclusion: Adjunctive homecare sub-gingival irrigation produced a significantly greater reduction in systemic inflammatory burden (CRP) than conventional hygiene, mirroring superior periodontal inflammatory control, but did not confer an additional glycaemic benefit at six months. In well-controlled diabetic patients, the systemic dividend of enhanced home care appears to be anti-inflammatory rather than directly glycaemic, consistent with NSPT itself being the principal driver of HbA1c change.