OBSERVATIONS ON EXPERIMENTAL DENTAL CARIES

Summary. The effect of adding to the drinking water unstimulated and untreated saliva from two human subjects who had markedly different caries susceptibility, on dental caries activity has been tested in hamsters. Three experimental groups were reared from weaning on the same cariogenic diet, the only dietary difference consisting in the quality of the drinking fluids. Group 1 received water mixed with saliva from a young female subject markedly caries‐susceptible. Group 2 was given water mixed with saliva from a young male subject markedly caries‐resistant, and group 3 received water alone. The results show that the animals which received saliva from the caries‐resistant subject exhibited less caries activity. It is therefore concluded that the saliva from the caries‐resistant individual contained a factor (or factors) which was able to decrease dental caries activity. Furthermore, these studies have demonstrated the existence in human saliva, at least in saliva of sexually mature individuals, of an unrecognized growth factor (or factors) which increase markedly the growth of hamsters, at least under the conditions of the present experiment.