When we speak of oral habits, we are typically speaking of any thumb, finger, or pacifier habits that may be causing damaging effects to the normal growth and development due to sucking or biting habits of the child. This type of sucking is completely normal for babies and young children.
Babies begin to suck on thumbs and fingers before they are born.
It provides security for them. Most children stop sucking on thumbs, pacifiers, or fingers on their own between the ages of two to four years. No harm is done to their teeth or jaws. However, some children continue these habits much longer, and this is where problems can occur. Habits can be responsible for a number of problems.