Neopterin Levels in Periodontitis and after Nonsurgical Periodontal Therapy: Evaluation of Gingival Crevicular Fluid, Oral Fluid, Serum and Urinary Samples—A Case-Control Study

Periodontitis is a chronic inflammatory disease that leads to the destruction of the tooth-supporting tissues with complex immune response. Neopterin (Np), secreted via activated macrophages, is considered a biomarker of cellular immunity. The aim of this study was to evaluate the impact of periodontitis and nonsurgical periodontal therapy. Np gingival crevicular fluid (GCF), oral fluid, serum and urine levels were compared in subjects with periodontitis before periodontal treatment, three months after and in a healthy control. Np GCF concentrations in the study group after treatment were significantly higher than the control group (p = 0.038). The GCF total amount (amount of substance) was significantly higher in the study group before periodontal treatment than in the control group (p = 0.001) and higher than the levels taken after treatment collection (p = 0.024). The oral fluid Np concentrations in the study group after treatment were significantly increased compared to the before treatment concentrations (p = 0.020). The same trend was observed in the urine samples. Significant correlation was found between the serum and oral fluid Np concentrations (p = 0.001, ρ = 0.40). Our results confirm the impact of cellular immunity and macrophages on periodontitis and on the resolution of periodontal inflammation. The presence of neopterin in oral fluid most likely originates in the serum.