Theory-based educational intervention on oral hygiene behavior among university students: a randomized controlled trial

Objective: The objective was to assess the effectiveness of the theory-based educational intervention tailored to the Theory of Planned Behavior (TPB) and behavior change techniques (BCTs) on oral hygiene behavior among university students through the oral hygiene behavior index and oral health outcomes. Materials and methods: A randomized controlled trial involving university students was conducted from November 2022 to March 2023 (n = 71). Participants were randomly assigned to a control group (n = 38) or an intervention group (n = 33). The control group received conventional dental health education, whereas the intervention group underwent a 21-day TPB-based educational intervention delivered through a three-minute video. Oral hygiene behavior index (OHBI) and oral health outcomes, including caries activity, salivary hemoglobin level, and total bacterial count, were assessed at baseline and three-month post-intervention. Results: Statistically significant improvements were seen in the OHBI score between groups and within the intervention group at three-month follow-up, with higher scores indicating better oral hygiene behavior. In addition, caries activity and salivary hemoglobin level were also improved. The total bacterial count in the intervention group did not show any statistically significant difference, even though it was lower than that of the control group. Conclusion: This study indicates that theory-based educational intervention tailored to TPB and BCTs improves oral hygiene behavior and certain oral health outcomes. Future studies should examine the long-term effects and generalizability in diverse populations. Trial registration: Thailand Clinical Trial TCTR20230105003. © The Author(s) 2025.