Family behavior theory-based intervention via mobile messaging to improve oral health of adolescents: study protocol for a cluster randomized controlled trial

Background: Due to some unique physical, social and psychological features in the adolescent population, adolescents can be a time of heightened caries activity and periodontal disease. Oral health-related behaviors can be modified to improve oral health status. The family networks and the built environment can promote or inhibit health behaviors. The aim of this study is to implement and evaluate a behavior theory-based, integrated family intervention via mobile messaging to improve oral health of adolescents. Methods: This is a three-arm parallel-design cluster-randomized controlled trial. This trial will allocate 12 local secondary schools (clusters) in Hong Kong to three test or comparison groups with a ratio 1:1:1. The enrolled Form II to IV students (ages 12 to 15) will be eligible for participation. The intervention to three study groups will be (i) Health Belief Model (HBM)-based mobile messaging to the adolescents and their parents, which will consist of several blocks of HBM-based messages and reinforcement during 24 weeks; (ii) same HBM-based messaging to adolescents only; and (iii) delivering e-version of oral health education pamphlets to adolescents. The primary outcome will be caries increment 2 years post-intervention. Changes in oral health self-efficacy and behaviors, oral hygiene, and gingival status will be the secondary outcomes. Discussion: No school dental care service is available to secondary school students in Hong Kong. This study will be the first to test a theory-driven and family-engaged preventive intervention among adolescents in Hong Kong. Findings will contribute to developing a low-cost, feasible, and efficient oral health preventive program for adolescents.