Saliva Analysis of pH and Antioxidant Capacity in Adult Obstructive Sleep Apnea Patients

Background: Obstructive sleep apnea syndrome (OSAS) may be associated with and activates the stress response system, and variation in the physiological antioxidant capacity of body fluids. Our aim was to evaluate the variation of pH and antioxidant capacity on the saliva of obstructive sleep apnea subjects (OG) compared to a control group (CG). Method: Fifty subjects with moderate/severe OSAS were recruited in Tor Vergata Hospital and compared with 20 healthy subjects CG. The buffer and the antioxidant capacity of the samples were quantified measuring the pH and the percentage of total salivary antioxidant capacity (%TAC), which refers to the reduced glutathione salivary concentration (GSH). Moreover, the protein concentration and the gelatinolytic activity of metalloproteinases were quantified. Results: The data showed that the pH value is slightly more alkaline in OSAS subjects; however, it is not directly related to the severity of OSAS. The %TAC was found to be significantly reduced by 86.2% in the OG. Proteins of saliva from the OG were found 1.5 times more concentrated than in the healthy sample. The gelatinolytic activity of metalloproteinases of healthy and OSA did not show statistically significant changes. Conclusions: The salivary samples from OSAS compared to CG show an alteration of the oxidative state, the pH buffering power, and protein concentrations, inducing conditions that can easily evolve chronic gingivitis. Further investigations are necessary to evaluate the feasibility of using salivary fluid for the early diagnosis of oral or systemic problems in OSAS subjects.