Marked differences in the prevalence of dental caries have been observed in two isolated villages in Colombia, South America. These differences approximate those observed between areas of minimal and optimal fluoride ingestion, although each village has less than 0.1 ppm fluoride in the drinking water. Dietary histories reveal remarkedly similar dietary practices. Samples of drinking water were collected from these villages, and analyzed by emission spectroscopy for the concentrations of 21 trace elements. In the case of 13 elements, concentrations were at or below the threshold of detection or showed minimal variability. Concentrations of calcium, magnesium, molybdenum and vanadium were higher in the water samples from the village with the low caries prevalence, while concentrations of copper, iron and manganese were higher in the samples from the village with the higher prevalence. These differences were highly significant. The caries prevalence in the high caries village was typical of the country as a whole.
