Composition of whole unstimulated saliva of healthy children: changes with age.

Whole unstimulated saliva was collected from 136 healthy subjects divided into 5 groups according to age: (1) 25 infants, 7-11 months old; (2) 28 toddlers, 2-3 yr old; (3) 28 children, 6-8 yr old; (4) 28 adolescents, 12-14 yr old; (5) 27 adults, 25-63 yr old. The concentrations of Na, K, total protein, IgA and amylase activity were measured. A significant ascending linear correlation with age was found for concentrations of Na, total protein, IgA and amylase activity. There were significant differences between age groups in K and IgA concentrations. Salivary amylase activity was very variable, and a significant difference was found between infants and toddlers only. Salivary composition thus changes significantly during childhood, implying a process of development and maturation of the salivary glands and indicating the need of age-matched controls for the clinical use of saliva.