The sooner the better! Starting at the first sign of a tooth, you should clean your child’s gum and tooth with a very tiny smear of fluoride toothpaste twice daily with an aged appropriate soft brush.
Once children are 3 years old and can spit out the toothpaste, then the amount should be increased to a pea sized dollop. You should also perform or assist your child’s tooth-brushing. Remember that young children do not have the ability to brush their own teeth effectively.