Dentists can be divided into five adoption categories based upon their time of adoption of pit and fissure sealants: innovators, early adopters, early majority, late majority, and laggards. The differences among dentists in the five adoption categories were examined for four classes of variables: practice characteristics, dentist characteristics, communication of information, and practice environment. Questionnaires were mailed in September 1984 to a random sample (N = 521) of Washington State dentists in general practices. A total of 376 completed questionnaires were returned, for a response rate of 72 percent. Adoption of sealants proceeded as follows: 5 percent of dentists through 1973, 24 percent through 1979, 50 percent through 1982, and 75 percent through 1984. Adoption category was related to percent of assistants who were certified, delegation to assistants and hygienists, magnitude of the fees charged by the practice, number of staff meetings per month, the dentist having been an officer in a dental organization, year the dentist adopted other new technologies, dentist's self-rating of willingness to try new things, percent of patients who are children, and percent of the dentist's colleagues who used sealants. These data lend some support to the two-stage or opinion-leader model of diffusion and suggest that new technologies can be promoted by first influencing dentists who consistently adopt early.