SALIVARY PARAMETERS OF RELEVANCE FOR ASSESSING CARIES ACTIVITY IN INDIVIDUALS AND POPULATIONS

A review of the non-microbial salivary parameters with respect to thei r possible association with caries activity is presented. The paramete rs are limited to those which already are or at least in the near futu re will obviously be simple enough, also for clinical purposes. Saliva ry flow rate is undoubtedly the most important single parameter since the cariostatic activity or efficacy of practically all other salivary parameters depends on the flow rate. Flow rate as such has no linear association with dental caries but there seems to exist an individual ''threshold'' limit which is decisive for enhanced caries activity Thi s threshold limit varies among different individuals and therefore the so-called normal values for unstimulated or stimulated flow rate are more reliable on a population level than among individuals for screeni ng purposes. In any individual a regular and longitudinal follow-up of the flow rate is of higher clinical value than only a single cross-se ctional measurement. Salivary buffer effect has only a weak negative a ssociation with caries activity and again, this effect is of greater c linical significance on a population level. Since the decisive process es in caries attack occur within or under the dental plaque, the buffe ring effect of saliva is limited and obviously more important to scree n for erosion- than caries-prone individuals. Although important for d ental health, none of the salivary antimicrobial agents as such has sh own any strong association with caries activity. The only ones with so me evidence of a regulatory role are secretory IgA antibodies, hypothi ocyanite ions, and agglutinins. However, the data are controversial an d it seems that instead of measuring individual parameters, the assess ment of saliva's functional properties (such as the ability to aggrega te bacteria, prevent their adhesion to hydroxyapatite or sugar metabol ism etc.) is more important for clinical purposes. Of the parameters i nvolved in de- and remineralization process, only salivary fluoride co ntent has some association with caries susceptibility but its diagnost ic or predictive value is questionable.