The goal of this cluster randomised controlled trial is to learn if an interactive video- and game-based oral health education intervention helps improve oral health outcomes among 11-year-old schoolchildren in Pulau Pinang, Malaysia. The main questions it aims to answer are:

• Does the intervention improve oral hygiene status?
• Does the intervention improve oral health knowledge, attitudes and hygiene practices?
• Does the intervention reduce the frequency of consuming foods that can cause tooth decay (cariogenic foods)?

Investigators will compare a group that receives the video- and game-based oral health education intervention along with a conventional oral health talk to a group that receives only the conventional oral health talk. This will help determine whether the video- and game-based oral health education intervention is more effective than the conventional oral health talk alone.

Participants will:

• Receive either three weekly sessions of the video- and game-based oral health education intervention in addition to a conventional oral health talk, or only the conventional oral health talk.
• Take part in assessments, including a clinical examination to check oral hygiene status and a self-administered questionnaire on oral health knowledge, attitudes, hygiene practices and frequency of cariogenic food consumption. These assessments will take place at three time points: before the intervention, one month after and three months after the intervention is completed.

This is a two-arm, parallel-group, single-blinded, cluster randomised controlled trial evaluating the effectiveness of an interactive video- and game-based oral health education intervention among 11-year-old schoolchildren in Pulau Pinang, Malaysia.

The allocation follows a 1:1 ratio. One district will be randomly selected and assigned to the intervention group, and another to the control group, using computer-generated random numbers in IBM SPSS Statistics for Windows, Version 29. Within each district, two government national primary schools will be randomly selected, and from each school, two classes will be randomly chosen. All eligible students in the selected classes, with written parental/guardian consent and written participant assent, will be included.

The control group will receive a conventional oral health talk provided through the school dental service. The intervention group will receive three weekly video- and game-based oral health education sessions delivered by the principal investigator, in addition to the conventional oral health talk.

Assessments will be conducted at three time points: pre-intervention, one month post-intervention and three months post-intervention. The primary outcome is oral hygiene status, while secondary outcomes include oral health knowledge, oral health attitudes, oral hygiene practices and frequency of cariogenic food consumption. Oral hygiene status will be assessed by a calibrated clinician using the Simplified Debris Index (DI-S) while secondary outcomes will be assessed using a validated self-administered questionnaire. The trial is single-blinded, with clinical examiners blinded to group allocation.

Sample size was calculated using G*Power software version 3.1.9.7 for repeated measures Analysis of Variance (ANOVA) (between factors). Assuming an effect size of 0.25, α = 0.05, power = 0.8 and a correlation of 0.5 among repeated measures, the required sample size is 86 participants. After adjusting for a 20% attrition rate and a design effect of 2 for cluster randomisation, the final sample size is 216 participants (108 per group).

All data will be analysed using IBM SPSS Statistics for Windows, Version 29. Descriptive statistics will summarise the data. Pre-intervention between-group comparisons will be conducted using the Pearson chi-square tests for categorical variables and independent t-tests for numerical variables. Mixed ANOVA will be used to assess and compare oral hygiene status, oral health knowledge, oral health attitudes, oral hygiene practices and frequency of cariogenic food consumption within and between the intervention and control groups at various time points (pre-intervention, one month post-intervention and three months post-intervention). If needed, mixed Analysis of Covariance (ANCOVA) will be performed to adjust for potential confounding factors. When significant effects are observed, post-hoc pairwise comparisons will be conducted to identify specific time points with significant differences. A significance level of p<0.05 will be applied.

Inclusion Criteria:

• Schoolchildren who are Malaysian citizens.
• Schoolchildren born in year 2014.
• Schoolchildren studying at government national primary schools under the Ministry of Education Malaysia.
• Schoolchildren who are able to understand, read and write in Malay language.

Exclusion Criteria:

• Schoolchildren with underlying chronic medical conditions.
• Schoolchildren wearing intra-oral appliances.
• Schoolchildren with learning or intellectual disabilities.
• Schoolchildren with impaired manual dexterity.
• Schoolchildren with visual or hearing impairments.

Data can be shared upon reasonable request and in accordance with applicable data protection regulations.