Development and validation of “OHL-Ortho” measurement tool and causal model of oral health behavior among adult orthodontic patients

Aim: Oral health literacy (OHL) significantly influences oral health behavior (OHB) and plays a crucial role in effective oral health promotion and achieving improved outcomes. This research aims to develop a measurement tool for evaluating OHL, named “OHL-Ortho,” and OHB in orthodontic patients. Furthermore, the study explores the extended causal relationship model from OHL to OHB. Materials and Methods: A cross-sectional exploratory study was conducted between February and June 2023 among Thai working-age adults undergoing fixed orthodontic appliances. Participants were randomly selected and stratified from diverse healthcare facilities. OHL and OHB questionnaires were developed and subjected to confirmatory factor analysis (CFA). Descriptive statistics and structural equation modeling were utilized to analyze data and evaluate the causal relationship between OHL and OHB. Results: The sample consisted of 321 participants, with an average age of 28.44 ± 7.56 years. Regarding construct validity, the 31-item OHL Scale achieved an overall Cronbach α of 0.97, with factor loadings ranging from 0.52 to 0.85. Similarly, the 14-item OHB Scale achieved an overall Cronbach α of 0.89, displaying factor loadings ranging from 0.42 to 0.64. Additionally, the causal relationship model of OHB aligned with empirical data, indicating that OHL exhibited a highly significant positive direct effect on OHB at a level of 0.01 (effect size = 0.81), explaining 66.00% of the variance in OHB. Conclusion: The developed scales serve as high-quality assessment tools for healthcare providers. The study underscores the significant impact of OHL on OHB among orthodontic patients.