An experimental study of lithium and dental caries in the rat.

Lithium chloride, given via the drinking water, was tested for its effect on dental caries. In a preliminary experiment lithium at concentrations of 0, 5, 20, 40, 60, 125 and 250 microgram/l showed a significant dose-related effect by ANOVA with the lowest smooth-surface scores at 20 microgram Li. Lithium was also used at 20 microgram/l with and without fluoride at 5, 10 and 20 mg/l. No greater effect on caries was seen of the lithium-fluoride combination than fluoride alone. Using 0, 5, 20 and 40 microgram Li/l, and larger groups of rats, a trend for lower caries was seen but the variance of the data was too large to be statistically significant. Despite a number of epidemiologic studies associating low caries prevalence with lithium, animal model research has not demonstrated a clear reduction in caries due to lithium added to the drinking water.