Mobile-health Intervention to Promote Oral Health in Adolescents: A Cluster Randomized Controlled Trial

The investigators propose a 30-months clustered randomized controlled trial to investigate the effectiveness of Health Belief Model (HBM) and family-based mobile-health intervention in enhancing the adolescents' good oral health behaviors and preventing oral diseases. This is a three-arm parallel-design cluster-randomized controlled trial. Parents and their children (12 to 15-year-old) will be recruited and randomized into 3 groups based on the school sites. Messages targeted on six domains guided by HBM will be sent to the adolescents and their parents via mobile phone. Two blocks of HBM-based oral health messages, reminders, feedback and reinforcement messages will be delivered to both students and parents by mobile phone for 24 weeks; while the intervention of the other 2 groups will target on students only or using prevailing oral health education. The primary outcomes will be caries increment of the adolescents 2-year post-intervention. Change in oral health self-efficacy and behaviors, dental plaque and gingival bleeding index will be the secondary outcomes. The investigators anticipate the proposed family- and HBM-based behavioral intervention is more effective than HBM-based mobile-health intervention on adolescents alone or prevailing oral health education in improving the adolescents' oral hygiene behaviors, reducing free-sugar intake and preventing oral diseases.