Interaction of age and specific saliva component output on caries

Background and aims: The purpose of this study was to explore the relationship between individual salivary components, dental caries and age, utilizing the data from the Oral Health: San Antonio Longitudinal Study of Aging (OH:SALSA). Methods: The study population comprised a well-defined stratified sample of 811 dentate men and women. Subjects were divided into four age groups from 35 to 75+ years old. Unstimulated and stimulated submandibular/ sublingual saliva flow rates, unstimulated and stimulated parotid saliva flow rates, total protein, 6 individual proteins and 4 in-organic constituents were measured. Specific salivary components were lactoferrin, secretory IgA, albumin, lysozyme, mucin, cystatin, K⁺, Ca⁺², Na⁺ and Cl^-. Caries measurements were the DMFT Index for crowns and for roots, Tooth Health Index for crowns and roots, Tooth caries, Root caries and Tooth restoration. The data on saliva components were square root transformed for linearity prior to analysis. Analysis was carried out in two stages. Partial correlation was performed, in order to identify significant relationships between specific salivary components and caries measurements, controlling for age group. In the second stage, using caries measurement as the dependant variable, the effects of age, flow rate and specific salivary component output (product of flow rate and concentration) were examined. Results: Significant associations were found between caries, age and specific individual submandibular/sublingual salivary proteins (lactoferrin, albumin, lysozyme, mucin and cystatin) and specific inorganic constituents (K⁺, Ca⁺², Na⁺ and Cl^-). Conclusions: Changes in submandibular/sublingual salivary component output during aging are correlated with high caries prevalence. These changes in saliva components over age may represent caries risk indicators.