Metabolic differences between saliva from caries-active and caries- and restoration-free children

Abstract

Sucrose consumption and lactic-acid production by saliva, and the effects of pH, were first evaluated by radio-isotope techniques in populations of caries- and restoration-free (CF), and caries-active (CA) children, with early mixed dentitions. Saliva of CF subjects formed significantly more lactic acid from sucrose than saliva from CA subjects. Sucrose consumption also was significantly greater in saliva of CF subjects. These results occurred at pH 7.2 but not at pH 6.0 and 5.0. Lactic acid, total volatile products and carbon-dioxide (CO 2) production by saliva were then evaluated in different CF and CA populations of children. Metabolic parameters in the presence and absence of salivary supernatant (SS) also were determined. Saliva of these CF subjects also formed significantly more lactic acid from sucrose than did CA subjects. The presence of SS increased lactic-acid formation in this saliva; the increase was significant in CF subjects. Total volatile products and CO 2 were greater in saliva of CF subjects but were not affected by SS. Partial microbial characterization of each salivary specimen was conducted in both series of experiments. CF subjects harboured less Streptococcus mutans (parts I and II), total lactobacilli (parts I and II) and Actinomyces species (part II) than CA subjects. Differences for lactobacilli in the first population and Actinomyces species in the second were significant.