Makeeva IM, Budina TV, Turkina AY, et al. - In this simultaneous cohort observational clinical study, researchers reported the xerostomia prevalence and severity in patients with obstructive sleep apnoea (OSA) and evaluated the saliva pH in patients with OSA. The sample consisted of 30 patients with OSA aged from 35 to 65 years. According to results, 22 out of 30 (73.3%) patients were diagnosed with "dry mouth". Data reported that the average salivary flow rate was 0.28 mL/min, 0.24 mL/min and 0.14 mL/min, respectively. The saliva amount and rate are similar in patients with mild and moderate OSA. Both these parameters are changing with the rise in OSA severity. The acidity of the saliva was correlated with the level of OSA and increased statistically with the increase in OSA severity.