The Copper and Cobalt Levels of Human Saliva and Dental Caries Activity

Abstract

Of the 4 trace elements antagonistic to the growth of oral acidogenic bacteria in synthetic media, saliva contains Cu regularly, Co occasionally, and Ni and Mo not at all. Cu was present in amts. ranging from 10 to 47.5 mg. per 100 ml. in each of the 48 samples of saliva analyzed for this element. Co was present in 10 of 37 samples, the maximum concn. being 12.53 mg./100 ml. of saliva. In vitro studies clearly demonstrate that the Cu and Co levels of saliva bear no relationship to dental caries activity. The removal of these elements by chelation did not materially affect acid production in saliva. When added to a synthetic medium in the amts. present in saliva, these elements failed to influence the growth of an oral strain of Lactobacillus acidophilus. The concns. of Co++ Cu++ required to inhibit acid production in human whole saliva greatly exceeds those found to be actually present in this medium.