Salivary antioxidants as periodontal biomarkers in evaluation of tissue status and treatment outcome

Background and objective: One of the major pathologic patterns in periodontitis represents an imbalance among the production of free radicals and local antioxidants resulting in periodontal tissue destruction. The objective of the study was to investigate the influence of non-surgical periodontal treatment on salivary antioxidants and to evaluate their capacity as biomarkers reflecting periodontal tissue condition and therapy outcome. Material and Methods: Sixty-three systemically healthy non-smokers, including 21 periodontally healthy subjects (HC) and 42 patients with current chronic periodontitis fulfilled the inclusion criteria. Half of the patients received scaling and root planing (SRP) and the other half received only oral hygiene instructions. Full mouth clinical measurements, including gingival index (GI), plaque index (PI), periodontal pocket depth, clinical attachment level and saliva sampling were performed at baseline visit and 2 mo after treatment/baseline visit. Total antioxidant capacity (TAOC), albumins (ALB), uric acid (UA), superoxide dismutase (SOD) and glutathione peroxidase (GPX) were evaluated in saliva samples using commercial kits. Results: All measured antioxidants were affected by treatment resulting in significant increase in TAOC (p < 0.005), ALB (p < 0.001), UA (p < 0.001) and GPX (p < 0.001) and decrease of SOD (p < 0.005) in response to SRP, where no differences were observed for any of parameters in the oral hygiene instructions group. Comparison of antioxidant levels between the HC and SRP group showed that before treatment ALB were significantly higher in HC when compared to the SRP group (p = 0.039), and GXP (p = 0.000) and SOD (p = 0.021) levels were significantly higher in the SRP group. Comparison of values after treatment showed that TAOC was significantly higher in the HC than in the SRP group (p = 0.001), but UA was, inversely, significantly higher in the SRP group (p = 0.034). All clinical parameters except clinical attachment level were significantly decreased after SRP and significant correlations were observed between SOD and GI (p = 0.017), SOD and PI (p = 0.011), GPX and GI (p = 0.003) and GPX and PI (p = 0.008). Conclusion: Non-surgical periodontal treatment affected salivary TAOC, ALB, UA, SOD and GPX; moreover, these biochemical parameters convincingly reflected periodontal status and tissue response on treatment.