Adolescence is a phase of important redefinitions and become an important period in the construction of new habits. Therefore, oral health education becomes strongly necessary, since good habits acquired at this stage may be perpetuated for adult life. The aim of this study is to evaluate the influence of an educational protocol on oral health in oral knowledge and clinical conditions in adolescence. A longitudinal study is being conducted with an initial sample of 291 adolescents enrolled in a public school in the city of Curitiba, Paraná, Brazil. The educational protocol was built in four phases. In phase I, the participants answered a questionnaire (pre-test) that included five statements about periodontal diseases and their forms of prevention. The answers were arranged in a Likert scale with a score of 1 (one) for the correct responses and 0 (zero) for the incorrect ones, obtaining, therefore, the knowledge score (KC). At this stage, adolescents is also being clinically assessed using simplified oral hygiene index (IHO-S) for dental plaque evaluation and gingival bleeding (ISG). In phase II, the sample (n = 291) is being randomly divided into two groups that receive two different educational interventions: oral orientation (OR) and video (VD). After each intervention, the questionnaire (post-test) is being reapplied. In the next phase (III), the study population (n = 291) is being again divided into four groups, and for two of them (OR + APP / VD + APP) a smartphone app was developed to messages which are being sending over a period of 30 days. In phase IV, the participants (n = 263) are answering again to the questionnaire (follow-up test) and are being reassessed clinically. Non-parametric tests and univariate and multivariate Poisson regression with robust variance will be used for statistical analysis (α = 0.05).
