This prospective randomized controlled trial will aim to evaluate the effectiveness of two methods of delivering oral hygiene instruction to children aged 3 - 6 years: parent-modeled toothbrushing (control) and the MoodBrush digital application (experimental). The primary endpoint is the change in plaque index scores before and after brushing, measured on 12 tooth surfaces using the Silness and Loe Plaque Index. The study rationale is based in the need to identify efficient and engaging strategies to improve pediatric oral hygiene. The expected outcome is that both groups will demonstrate significant reductions in plaque scores, with children using MoodBrush achieving similar, if not greater improvements in plaque index scores. Follow-up includes an immediate post-brushing assessment at the dental visit, with intrarater reliability checks to ensure measurement consistency. Statistical analyses will include paired t-tests to evaluate pre-post changes within groups and two-sample t-tests to compare differences between groups, with significance set at p \< 0.05. A sample size of 112 participants provides 80% power to detect a mean difference of 0.30 in plaque index score reduction.