Determination of salivary biomarkers of oxidative stress, nitric oxide levels and alpha-amylase activity in individuals with and without caries

Abstract

Dental caries is a disease resulting from the demineralization of dental structures, in which saliva plays a fundamental role due to its buffering properties. In addition, saliva has antimicrobial and antioxidant substances in its composition, being part of defense mechanisms against the oxidative and nitrosative stress caused by the increased production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in systemic and oral pathologies. Thus, this study aimed to quantify the markers of oxidative stress, nitric oxide levels (NO) and alpha-amylase activity (AA) in saliva of individuals with and without caries, and therefore establish the characteristics of the oral cavity related to this disease. Saliva samples were collected from patients with (n=30) and without caries (n=30), the pH and salivary flow were measured and the following analyses were performed: lipid peroxidation (TBARS), total antioxidant capacity (FRAP), reduced glutathione levels (GSH), superoxide dismutase activity (SOD), Catalase activity (CAT), AA activity and NO levels. Results were expressed as mean ± SEM and compared by the student's t test (p<0.05). No differences were observed between the groups in the analyses of pH, salivary flow, TBARS, FRAP, GSH, AA and NO. It was observed an increase in SOD and CAT activities in the caries group. The increased activity of these enzymes may be related to the higher production of free radicals in this group and possibly consists of an initial compensatory mechanism responsible for the reduction of oxidative damage. These results allow us to better understand the mechanisms of oxidative stress involved in this disease and provide oral biochemical characteristics related to the establishment of caries.