Community-based educational activities have been introduced into health education programs across the world. However, research on students' perceptions of their experiences in these settings has been limited. The objectives of this study were to assess a group of Brazilian dental students' views of their experiences in a service-learning program focusing on pediatric dental care and to explore changes in their perceptions over the course of the program. Data were collected from fifty-five fourth-year dental students, who submitted a total of 185 reports at four points in time. The students spent sixteen of the 128 hours of their pediatric dentistry course in community-based education developing activities linked to pediatric dental care. Two professors rated each report as a positive or negative experience (Kappa 0.7) and recorded whether the students' reports reflected one or more of five types of response. The response types concerned dental treatment practice, multidisciplinary activities, observation of infant/toddler consultations, commitment of the outreach health team, and change of plans due to technical problems. The data showed that the students had a positive first impression after a short stay in a community-service program, but there was a decrease in the students' positive experiences over time (p<0.001). The students' perceptions of the outreach health team as "being not committed" (OR 6.82, 95 percent CI 2.12-21.90) and experiences of a "no change of plans due to technical problems" (OR 0.09, 95 percent CI 0.04-0.20) associated with negative student experiences.