Salivary secretion, taste and hyposalivation.

Saliva has many essential functions. As the first digestive fluid in the alimentary canal, saliva is secreted in response to food, assisting intake and initiating the digestion of starch and lipids. During this process, saliva acts as a solvent of taste substances and affects taste sensitivity. Clinically, a more important role is in the maintenance of oral health, including the protection of teeth and mucosa from infections, maintenance of the milieu of taste receptors, and communication ability through speech. Variations in salivary flow can be affected, reversibly or irreversibly, by numerous physiological and pathological factors. Decreased salivary flow results in clinically significant oral discomfort that may manifest as increased caries, susceptibility to oral candidiasis, altered taste sensation or as a host of other problems. Hyposalivation is a condition that is frequently encountered in dental practice. The most common cause is the use of certain systemic medications, which put the elderly at greater risk because they are usually more medicated. Other causes include high doses of radiation and certain diseases such as Sjögren's syndrome. This article reviews the mechanism of salivary secretion, effect of saliva on taste, importance of saliva in oral health, and hyposalivation in relation to ageing, medicine and/or disease and management of hyposalivation.