Development and Initial Psychometric Evaluation of the Adolescent Oral and Maxillofacial Health Knowledge–Attitude–Practice and Self-Efficacy Questionnaire (AOMH-KAPQ)

Background/Objectives: Existing oral-health questionnaires differ in scope from an instrument that combines objectively scored knowledge with separate attitude, practice, and self-efficacy domains across multiple adolescent oral and maxillofacial topics. This study developed the Adolescent Oral and Maxillofacial Health Knowledge–Attitude–Practice and Self-Efficacy Questionnaire (AOMH-KAPQ) and evaluated its initial psychometric properties. Methods: A 46-item pool derived from the KAP framework, literature, and clinical education content was refined through consultation with 18 experts and cognitive interviews with 10 adolescents. The questionnaire was administered to 1006 adolescents aged 12–18 years, and the sample was randomly divided for exploratory factor analysis (EFA) and confirmatory factor analysis (CFA; n = 503 each). Reliability, measurement invariance, and knowledge-item performance were also examined. Results: The final 38-item questionnaire comprised knowledge (15 items), attitude (9), practice (9), and self-efficacy (5). EFA identified one attitude and two provisional practice factors. In CFA, SRMR was ≤0.051 across dimensions; self-efficacy showed CFI = 0.991, TLI = 0.982, and RMSEA = 0.082, whereas robust RMSEA remained elevated for attitude (0.137) and practice (0.145). Cronbach’s α was 0.855–0.929, McDonald’s ω 0.867–0.930, and test–retest ICC 0.797–0.866. Conclusions: The AOMH-KAPQ showed good reliability in this sample, but structural evidence for the attitude and practice dimensions remains preliminary. At present, use should be limited to research and group-level educational needs assessment rather than individual clinical decisions.