Composition and flow rate of saliva and caries development in young rats following administration of lithium

Lithium carbonate (Li2CO3), an antipsychotic medication, was investigated to determine the effects on the stimulated flow and composition of saliva and on caries development in rats. Lithium carbonate was delivered via osmotic pumps at 10, 15 and 60 mg/kg/day. All animals were infected with Streptococcus sobrinus 6715 and fed a cariogenic diet. Lithium administration exerted a caries-protective effect on sulcal surfaces, though the reduction in caries scores was statistically significant only for the groups receiving Li2CO3 at 10 and 60 mg/kg/day compared to control animals (p +/- 0.05, ANOVA). There were no detectable alterations in protein concentration, electrophoretic profiles, or flow rates of stimulated parotid and submandibular saliva associated with the decreased sulcal caries incidence. Weight gain, water consumption and the populations of total cultivable flora recovered were not influenced by the administration of lithium. Investigation into the mechanisms of the sulcal caries reduction will require further exploration of changes caused by lithium on salivary gland function.