RESUMO
BACKGROUND: Adolescence is a decisive period in the construction of new conduits. OBJECTIVE: The influence of an App associated with conventional educational methods in adolescents' oral health. STUDY DESIGN: Randomized controlled trial including 291 participants (mean age = 16.1 years) in baseline. The study consisted of four phases. Interventions were evaluated through the knowledge score (KS) and oral indexes (OHI-S/GBI). KS was obtained through five affirmations about periodontal diseases applied in different moments (pre-test, post-test, and follow-up test). Phase I included pre-test and oral clinical examination. Sample was randomly divided into two groups: oral (OG) and video orientation (VG) and post-test (phase II). Phase III characterized the formation of groups: OG + App/OG without App/VG + App/VG without App. App consisted of reinforcement messages which was sent during 30 days. Phase IV comprised follow-up test and clinical evaluation. RESULTS: There was no significant difference in KS between OG/VG. Overall, App improved KS (P < 0.001). VG + App showed a significant increase in KS in the follow-up test compared to the post-test (P = 0.046). There was a significant reduction in oral indexes for all methods. CONCLUSION: App was effective in increasing knowledge, especially associated with video. The different methods were equally effective for a better standard in oral hygiene.