A very common habit babies have is thumb sucking. The first year or so, your baby may be prone to thumb sucking as a comforting mechanism. But if this habit continues on past the age of 4-5, it can contribute to an open bite. To encourage your child to help stop this habit, compliment your child whenever they are not sucking their thumb. A bandage on the thumb or a mit over the hand can remind them whenever they attempt to bring the thumb to the mouth to stop.