Topical fluoride comes in different forms: Gels, foams, rinse and varnish. Fluoride varnish (5% sodium fluoride) is usually used on infants, toddlers and children who cannot tolerate other forms of fluoride. It is very sticky and stays on teeth for a long time; therefore, your child can eat or drink water if he / she wants to. We ask parent not to brush teeth for the child for 4-6 hours, to avoid hard food or food with high temperature (such as hot cocoa) for 4-6 hours. If your child had fluoride gel, foam ( on trays) or rinse, we would ask the child not to eat, drink or rinse mouth for 30 min.