Tooth Decay in Kids Getting into a routine of regular dental care is one of the best ways for children to fight cavities. As young children develop more teeth at ages two to three years, the same general rules to fight cavities apply to them as for teens and adults: Visit a dentist regularly Eat tooth-healthy foods, including fruits, vegetables, and cheese Rinse with water if it isn’t possible to brush after each meal or snack Brush teeth at least twice daily using fluoride t