Nearly 30% of 35-60 years-olds in the U.S. have experienced tooth extraction resulting in spaces between remaining teeth. Treatment of this condition, the bounded edentulous space, costs in excess of $2.7 billion annually. There are five alternative treatment strategies for the condition, but their overall costs and consequences are not known. The sparse information describing clinical outcomes of the alternative treatments, coupled with the absence of any information about patient preferences for these treatments has resulted in a situation where several million substantive treatment decisions are based each year on little more than dentists' subjective impressions of effectiveness. This proposal describes cost-effectiveness and cost-utility analyses of the five alternative treatment strategies for a bounded edentulous space. The analyses will be based on Markov models to accommodate the complex set of recurring complications that accompanies most of the alternative treatments. Because the clinical outcomes of these alternative treatments are poorly defined, transitional probabilities for all health states in the Markov model will be determined through retrospective analyses of treatment records in four large provider organizations and data form a longitudinal epidemiology study, supplemented by information from a meta- analysis of the literature. Patient utilities for use in the cost-utility analyses will also be collected, and differences in utilities among patients experienced and not experienced with the alternative treatments will be examined. For the cost-effectiveness analysis, effectiveness is measured in terms of "treatment survival year." The cost-utility analysis will use a version of the same measure that has been "quality adjusted" for patient preferences. The results of the analyses will be useful in shared-decision making by patients and dentists concerning the replacement of a posterior tooth. Just as importantly, the results will represent the first step in the development of practice guidelines for replacement of a lost tooth, the most complex and expensive treatment routinely performed by general dentists. More broadly, the information will be important to the determination of appropriate dental health benefits by public and private purchases regardless of the exact outcome of any health care reform. Finally, because tooth loss is a terminal event in any dental treatment sequence, the results of these analyses are vital to virtually all other analyses of cost, effectiveness, and utility of dental treatment.