A longitudinal study has been conducting with an initial sample of 291 adolescents enrolled in high school at a public school in the city of Curitiba, Paraná, Brazil. The educational protocol is characterized by four phases. In the first stage (Phase I), the participants are answering a questionnaire (pre-test) in order to verify the level of previous knowledge of the sample regarding periodontal diseases and their forms of prevention and are being clinically examined. In phase II the adolescents are randomly divided into two groups, which receive different educational methods: oral orientation (OR) and the application of a video (VD). After the educational interventions, the participants answer the questionnaire (post-test). In phase III, the two groups are being divided into four subgroups: oral orientation with App (OR+App), oral orientation without App (OR without App), video with App (VD+App) and video without App (VD without App). OR+App and VD+App received a mobile phone application specially developed for this study containing educational messages which are being during a period of 30 days. In the fourth phase (IV) the participants answer the questionnaire again (follow-up test) and are reassessed clinically.