Objective: To investigate the impact of “Brush Up” - a mobile application, on oral hygiene behaviours of 4-6-year-old children in Bangalore city. Methods: In this experimental study, 247 children aged 4-6, were randomly divided into three groups. Considering “Brush Up” is a mobile application, parents of the children in Group 1 (n=82) downloaded the application on their smartphones. Children in Group 2 (n=83) and Group 3 (n=82) received tooth brushing instructions by an educative video and manual demonstration, respectively. Effectiveness of tooth brushing was assessed with plaque scores, which were recorded for all the groups at baseline and one month using Visible Biofilm Index. Results: Wilcoxon signed rank test showed a significant improvement in the tooth brushing behaviour for the Brush Up group, which was indicated by a lower plaque score after a follow-up of one month. Kruskal-Wallis test followed by post-hoc test showed that the mean ranks of plaque scores of Brush Up group are consistently lower than those of video demonstration group and manual demonstration group. Conclusions: The lower plaque score in subsequent follow-up in Brush Up group suggests that using a smart system can enhance learning a correct tooth brushing method in young children and can also help in implementing the required reinforcement and motivation to brush and aid in better plaque control.