Effects of Cations on the Cariostatic Activity of Orthophosphates

¹ Department of Nutrition and Food Science, Massachusetts Institute of Technology, Cambridge, Massachusetts

Mono- and di-basic salts of Na, K, and Ca orthophosphate were pulverized, incorporated in various proportions into a caries-producing diet in sufficient amounts to double the P content of this diet, and fed to groups of 30 rats for 90 days beginning when they were 8 days old. In comparison with the control group, the caries scores were reduced by 81 per cent, 71 per cent, and 29 per cent when the Na, K, or Ca salts, respectively, supplied two-thirds of the P supplement. The caries reduction was 45 per cent when these salts were added in equal amounts. Thus Na and K orthophosphates are highly effective in the prevention of experimental caries in rats, while Ca orthophosphate is only slightly cariostatic. Furthermore, the Ca salt appears to interfere with the action of Na and K orthophosphates when the three are fed together.