Assessment of Serum CRP and Gingival Crevicular Fluid OPG and Neutrophil Elastase as Biomarkers for Periodontal Disease in Type 2 Diabetes Mellitus

The objective of this study was to evaluate serum C-reactive protein (CRP) and gingival crevicular fluid (GCF) osteoprotegerin (OPG) and neutrophil elastase as biomarkers for periodontal disease diagnosis in patients with Type 2 diabetes mellitus (T2DM) compared with non-diabetic periodontitis patients and healthy controls. This case-control study included 90 participants aged 20–60 years, divided into three groups: healthy controls (n = 30), periodontitis with T2DM (n = 30), and periodontitis without diabetes (n = 30). Periodontal parameters (probing depth, clinical attachment loss, bleeding on probing, and plaque index) were recorded. Serum CRP was measured using a Cobas 411 analyzer, while GCF OPG and neutrophil elastase were assessed by ELISA. Data were analyzed using ANOVA with significance different (P < 0.05). Periodontal parameters were significantly higher in both periodontitis groups compared to controls. Serum CRP levels were highest in controls and significantly lower in periodontitis groups, with the lowest levels observed in non-diabetic periodontitis. GCF OPG levels were highest in controls and significantly reduced in disease groups; however, patients with T2DM showed intermediate OPG levels, significantly higher than those without diabetes. Neutrophil elastase levels were markedly elevated in both periodontitis groups, with the highest levels in diabetic periodontitis. A strong positive correlation between CRP and OPG was observed in the non-diabetic periodontitis group.