INFLUENCE OF MATERNAL LEAD INGESTION ON CARIES IN RAT PUPS

Lead is one of the most toxic and pervasive pollutants in society, and although there has been some lowering of blood lead levels in recent years, the levels continue to be of concern for African Americans, cen tral city residents, residents in the Northeast region of the United S tates, persons with low income, and those with low educational attainm ent(1). Notably, these are the persons and the region where the highes t prevalence of dental caries is observed. Information relating lead t oxicity to oral health is sparse, but the preponderance of epidemiolog ical data shows a relation between lead in the environment and the pre valence of dental caries(2,3). Using our well-defined rat caries model (4), we found that pre- and perinatal exposure to lead results in an a lmost 40% increase in the prevalence of caries and a decrease in stimu lated parotid function of nearly 30%. Levels of lead in milk from lead -treated darns were approximately 10 times as high as the correspondin g blood lead levels, suggesting that lead is being concentrated by mam mary glands. These findings may help in part to explain the comparativ ely high levels of dental caries observed in the inner cities of the U nited States where exposure to lead is common. Environmental sources o f lead include drinking water, lead-based paint and, to a lesser exten t, automobile and industrial emissions. In humans lead is accumulated and stored in bones (half-life of approximately 62 years(5)), and even maternal exposure to lead decades before pregnancy can subsequently r esult in exposure of the developing fetus to elevated levels of lead. Moreover, lead concentration in maternal blood has been shown to incre ase during pregnancy and lactation because of mobilization of stored l ead from bone(6), and typically, lead is found in milk at a higher con centration than the level found in maternal plasma at the same time po int(7).