Using mHealth to promote parents’ brushing of preschool children’s teeth: a protocol for a randomized factorial trial using the Multi-phase Optimization Strategy (MOST)

BACKGROUND: Early childhood caries is a highly prevalent disease affecting young children. Parental brushing of children’s teeth is recommended during preschool years. Interventions to promote parental brushing of children’s teeth are assessed as a package in randomized clinical trials and the efficacy of separate components is not known. METHODS AND ANALYSIS: The aim of this study is to develop an optimized behavior modification intervention to increase parents’ brushing of their pre-school children’s teeth using the multi-phase optimization strategy (MOST) guided by the Theory of Planned Behavior. Behavior change will be assessed by the percent reduction in children’s dental plaque index after 6 months and parents reporting of toothbrushing frequency. Two phases of MOST will be carried out. First, the preparation phase comprises the development of a conceptual framework, identifying candidate components, conducting a feasibility pilot study to assess the acceptability and the design features of three intervention components (motivational interviewing (MI), and two mobile health (mHealth) components: oral health promotion messages and storytelling videos delivered using WhatsApp messenger) in addition to setting an optimization objective. Second, the optimization phase constitutes a factorial trial assessing the three intervention components and developing the intervention by selecting the most effective components within the optimization constraint. Each component will be set at two levels: yes (the intervention is applied) and no (the intervention is not applied). A linear regression model will be used to assess the effect of the intervention components on the percent reduction in dental plaque index (primary outcome measure). The secondary outcome measure is the change in the frequency of parents’ brushing of the child’s teeth. The combination of components making up the new optimized intervention will be selected. DISCUSSION: This will be the first study to apply the MOST framework in the field of dentistry. The results of this study can guide the development of an optimized behavior modification interventions using mHealth and MI. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04923581, Registered 11 June 2021. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13063-021-05931-0.