Prognostic Value of 8-Hydroxy-2′-Deoxyguanosine and Human Neutrophil Elastase/α1-Proteinase Inhibitor Complex as Salivary Biomarkers of Oxidative Stress in Chronic Periodontitis

Background: 8-Hydroxy-2'-deoxyguanosine (8-OHdG) and human neutrophil elastase/alpha 1-proteinase inhibitor (HNE/alpha 1-PI) complex have been regarded as reliable biomarkers of oxidative stress in inflammatory conditions. This study investigates whether the salivary levels of these two analytes may be linked with periodontal health status. Methods: One hundred ten patients with chronic periodontitis (CP) and 50 healthy controls were selected. Periodontal status was assessed by criteria based on probing depth, clinical attachment level, and extent and severity of periodontal breakdown. 8-OHdG and HNE/alpha 1-PI salivary levels were analyzed by enzyme-linked immunosorbent assay. The association of these analytes with CP was analyzed individually and adjusted for confounding factors using a multivariate binary logistic regression model. Results: Significantly higher levels of both markers were detected in the CP group in comparison to controls. Weak-to-moderate positive significant correlations between salivary biomarkers and clinical parameters were observed. After binary logistic regression analysis, salivary levels of 8-OHdG > 17.35 ng/mL and HNE/alpha 1-PI complex > 158.28 ng/mL were independently associated with disease status. Interaction effects among candidate prognostic variables were also noted. Conclusions: Increased salivary levels of 8-OHdG and HNE/alpha 1-PI complex may be strong, independent prognostic indicators of the amount and extent of oxidative stress-induced periodontal breakdown. In addition, unstimulated whole saliva samples might reflect a synergistic biologic interactive effect of HNE/alpha 1-PI associated with the aging and smoking cumulative characteristics of periodontal damage.