Effects of Virtual Human–Based Oral Health Education on Adolescent Oral Health Literacy and Behaviors: A Cluster Randomised Controlled Trial

Background/Objectives: Adolescence is a critical period for establishing lifelong oral health behaviours; however, persistent oral health problems and limitations in conventional school-based oral health education (OHE) highlight the need for more engaging and scalable approaches. Emerging digital modalities, such as artificial intelligence (AI)-based virtual human (VH) education, offer a promising alternative but remain insufficiently evaluated in adolescent populations. This study aimed to evaluate the effectiveness of AI-based virtual human–based oral health education (VOHE) program compared with conventional face-to-face oral health education (FOHE) among adolescents. Methods: A cluster randomised pretest–post-test intervention design was employed. Participants received either VOHE or FOHE, followed by assessment using a structured questionnaire based on the Knowledge–Attitude–Practice (KAP) model. A total of 268 middle school students were assessed for changes in oral health literacy (OHL) and oral health-related KAP. A linear mixed-effects model was applied to evaluate the effects of time, group (VOHE vs. FOHE), and their interaction, with participants treated as random effects to account for within-individual correlations. Results: Both groups demonstrated significant improvements in OHL and oral health related KAP following the intervention (all p < 0.05). However, no significant group × time interaction effects were observed for any outcome variables (all p > 0.05), suggesting that VOHE achieved educational outcomes comparable to those of FOHE. These findings indicate that AI-based VH education may provide an effective and scalable approach for adolescent OHE. Conclusions: VOHE demonstrated effectiveness comparable to FOHE and may serve as a feasible alternative or complementary approach for adolescent OHE. AI-based VH education also has potential applicability as an accessible digital health intervention for school- and community-based oral health promotion, particularly in digitally mediated or resource-limited educational settings.