The purpose of this project is to study the response of 300 pre-school children to dental stress. Children 2 to 5 years old with no previous dental experience will be studied longitudinally for five years during periodic dental visits. Three factors will be examined: 1) the effect of age on the child's response to the initial dental experience and to continued periodic dental care; 2) the effect of non-stressful exam visits on the young child's response to eventual stressful treatment procedures; and 3) the effect of stressful treatment experiences on children's response to subsequent dental care. The child's response will be assessed using a combination of six measures: heart rate, skin conductance, picture test, human figure drawing, clinical ratings of anxiety and ratings of cooperative behavior. Currently, approximately 150 subjects are participating in the project. At the end of the first six months, the data gathered on the first 65 subjects was analyzed. The children's response to their initial series of visits was examined. The children's response deteriorated from the initial exam through the third treatment visit. Improvement was observed on all measures during the fourth treatment visit. The most favorable response was found during the polish visit. During the six month recall visit, response levels were similar to those recorded during the initial exam visit. The data suggested dental experience reduced the children's general apprehensiveness to the dental situation but sensitized them to specific stressful procedures. Their response during the recall exam suggested the benefits of dental experience were forgotten over the six months since their last dental visit.