DESCRIPTION: Despite the passage of nearly a century since the relationships among fluorides, Dental caries and fluorosis were first discovered, many aspects remain not well understood. The Iowa Fluoride Study (IPS), begun in 1991, has addressed this by longitudinally collecting detailed fluoride exposure/intake data from a cohort recruited at birth and relating these data to Dental caries and fluorosis exam findings for the primary and permanent teeth. We have reported extensively on longitudinal fluoride exposure patterns/intake, caries and fluorosis prevalence, and relationships among them for the primary dentition. Currently, we are conducting similar analyses related to the early mixed dentition. For the proposed continuation of the IPS project, we will longitudinally collect detailed fluoride exposure and dietary data at 6-month intervals from parents of over 600 participating cohort children ages 10 to 13, and a third wave of about 500 examinations for Dental caries (non-cavitated and cavitated) and fluorosis of the permanent dentition will be conducted. The primary focus will be to comprehensively examine the relationships among dietary and fluoride exposures, Dental caries and fluorosis. We also will determine how previous caries and fluorosis outcomes (ages 5 and 9) predict those at age 13. Specifically, analyses will focus on caries and fluorosis prevalence and extent in the late-erupting permanent dentition at age 13, and caries incidence from age 9 to 13. Age 13 dental fluorosis findings will be related to age 5 exam results, and Dental caries findings will be related to age 9 and age 5 exam results. Multivariable analyses will assess the relationships among longitudinally-collected data on various pre- and post-eruptive fluoride exposures and dietary patterns and the age 13 prevalence, incidence, and extent of caries and prevalence of fluorosis. Continuation of this landmark study will provide improved understanding of the relationships among fluorides, Dental caries and fluorosis. As studies involving recruitment and successful retention of a cohort from birth are extremely rare, the Iowa Fluoride Study offers a unique opportunity to study these relationships in unprecedented detail.