Advances in Dental Research, Vol 9, 239-243, Copyright © 1995 by International & American Associations for Dental Research
Salivary factors in caries models
D. I. Hay
Department of Biochemistry, Forsyth Dental Center, Boston, MA 02115, USA.
Consideration of salivary factors in caries models rarely extends beyond
viewing saliva as a sink or diluent for plaque metabolic products, or as a
source of buffering, for neutralizing plaque acids. In reality, saliva has
a complex chemistry and a wide range of biochemical activities that may
significantly affect plaque chemistry and microbiology. Thus, saliva is a
major source of microbial nutrients, without which bacterial acid
production is diminished. Buffering by salivary bicarbonate, and base
production from urea and basic amino acids and peptides, significantly
affect Stephan curves. Saliva is supersaturated with respect to basic
calcium phosphate salts and contains novel inhibitors of calcium phosphate
precipitation, while specific salivary proteins bind calcium. It seems
important to consider if this system is reflected in plaque. Saliva, with
contributions from serum and bacterial constituents, provides most of the
precursors for the acquired enamel pellicle, which acts to slow
demineralization during caries attack. Pellicle constituents appear to
influence initial bacterial colonization of tooth surfaces and, therefore,
may affect the microbial composition of plaque, but their detailed effects
on plaque are poorly understood. Microbial adaptations to the
anti-bacterial systems also seem important but are poorly investigated.
Thus, saliva possesses an array of activities that have substantial actual
or potential impact on plaque and, therefore, merit consideration for
inclusion in systems intended to model dental caries.
