Interventions
carious, tooth
Before the examination, all participants practiced tooth-brushing with our research team, were given dietary advice, and received a set of oral health care packages which included toothbrushes, fluoride toothpaste, dental floss, and leaflets on oral health education.The participants were randomly assigned to one of the three intervention groups: Group 1 (placebo control; water), Group 2 (5% NaF varnish [Duraphat, Colgate Palmolive, USA]), and Group 3 (38% SDF [Topamine, Dentalife, Australia]) using the stratified block randomization approach with a block size of six.All clinical procedures were performed at the participants’ schools by two dentists who were trained and calibrated to apply NaF varnish and SDF by pediatric dentist (V.J) prior to trial. The amount of apply NaF varnish applied per child was no more than 0.25 ml, and the amount of SDF applied per child was no more than 1 drop (25 µL).Before applying either placebo or topical fluoride, the teeth were cleaned with gauze and dental floss. A disposable micro-applicator was used to apply one of the topical fluoride treatments or placebo to all tooth surfaces, paying special attention to the proximal surfaces of posterior teeth and avoiding the pulp-involved carious surfaces. After intervention, the participants were instructed to refrain from eating or drinking for at least 30 min and were monitored by their class teachers. The interventions were performed every 6 months.