Signs of oral dryness in relation to salivary flow rate, pH, buffering capacity and dry mouth complaints

312 unmedicated healthy individuals belonging to three age groups, (6–11, 12–17, and 18–40 years) were examined clinically for signs of oral dryness. Resting and stimulated saliva were collected to determine flow rate, pH and buffering capacity. A questionnaire was used to obtain information on subjective sensation of dry mouth.Dry lip and dry mucosa were present in 37.5% and 3.2% of the sample respectively. The proportion of subjects who complained of oral dryness (19%) showed a stimulated salivary flow rate significantly lower than non complainers. Dry lip was significantly related to low resting flow rate but pH and buffering capacity did not show any significant relation to dry lip. Dry mucosa was not related to any of the above mentioned parameters.The finding that the stimulated salivary flow rate was reduced in subjects complaining of dry mouth is of great clinical relevance, since the reduction is expected to be reflected in compromising various salivary functions.In healthy individuals the oral tissues are constantly bathed with saliva. The constant flow of saliva eliminates food debris and bacteria by swallowing. When stimulated by chewing or by moderate strength citric acid, the whole saliva flow rate increases from the resting value of around 0.3–0.65 ml/min to around 1.5–6.0 ml/min [1,2] with great individual variations.Saliva has an important role in oral health by providing immunological protection, and its role as a reservoir of ions which aid remineralization of the calcified tissues [3]. The secretions of salivary glands are important for protecting the mucosa from feeling dry and according to Naito et al this oral dryness is contributing to reduce health related quality of life [4]. The perception of oral dryness (xerostomia) was found to be related to the rate of secretion of minor palatal glands [5,6]. The feeling of dryness was evident when the rate of that secretion was below 3 μL/cm3/min [7]. This suggests that the sensation of a dry mouth is