Most people have treatable dental disease, yet only half the U.S. population visits a dentist annually. Untreated dental disease is more common among poor, black, and less educated groups. Although lack of dental insurance had been considered a major factor underlying these utilization patterns, the Health Insurance Experiment (HIE) recently showed that even when care is free, most of those with caries do not receive treatment. Explanations of dental utilization behavior have been based primarily on studies focusing on one of five categories of variables: economic and sociodemographic; geographic and community characteristics; psychological variables; dental health status; and organizational features. Multivariate models are likely to yield the best and most useful information about how such variables effect dental utilization, yet few studies have examined several categories of explanatory factors together. Other limitations of prior research include: failure to study different types of dental utilization; reliance on cross-sectional designs and recall of behavior; and lack of attention to quality of measurement of explanatory variables and to important statistical issues. Using HIE data that have already been gathered and analyzed to estimate the effects of alternative financing arrangements on demand for dental services, this study proposes to develop and test multivariate models of dental utilization behavior using comprehensive specifications of explanatory factors and different definitions of dental use. The study will also address several important methodological issues common to this and similar studies. The multi-site design, rich files of well-measured explanatory variables, and prospective measures of dental utilization make the HIE data base uniquely suited for the proposed modeling work. Following exploratory analyses designed to replicate and extend results published by others, the proposed project will develop and test multivariate models of dental utilization behavior. The best models will be cross-validated in a random half of the HIE sample. In developing and testing hypotheses about why people use and do not use dental services, and the reasons for differences in the intensity of their care, emphasis will be placed on information most useful in informing the public policy debate about strategies for increasing the likelihood that dental services will be used when needed.