Inter-individual variation in saliva antioxidant status in relation to periodontal disease

Increased salivary antioxidant capacity has the potential to limit oxidative tissue damage and improve the health of the gingival tissues. In this thesis, the antioxidant profile of saliva was assessed in relation to periodontal health status. Salivary protein carbonyl concentration was assessed as a biomarker of oxidative tissue damage.;The major scavenging antioxidants in saliva were urate, ascorbate and albumin. Urate contributed 70% of the total antioxidant activity (TAA). Saliva flow rate followed a diurnal rhythm, peaking at 5.00pm with nadir at 3.00am. TAA followed a similar pattern. Saliva antioxidant flow rate was lower in individuals with severe periodontal disease, who also exhibited greater oxidative injury. In males TAA was significantly higher than in females, but no relationship was noted between sex and periodontal health. Sex differnces in TAA were unexplained although TAA and urate flow rates followed the same monthly cyclical pattern as progesterone and beta-estradiol in women. Nutritional intervention, in the form of antioxidant supplementation was found to have little effect on salivary antioxidant status with only a transient increase in ascorbate evident. Dental hygiene products, in the form of mouthrinses and toothpastes, were found to vary significantly in their antioxidant capacity, with those containing methylsalicylate having the highest antioxidant capacity.;These data suggest that severe periodontal disease is associated with a decreased salivary antioxidant flow rate and increased oxidative injury. In addition, dietary antioxidant supplementation does not appear to increase salivary antioxidant status as it does in plasma. The use of certain dental hygiene products may boost antioxidant capacity within the oral cavity, although in vivo studies are required to investigate this further.