The existence of an oral habit should be noted during the clinical examination of a child . If this habit is causing movement of the incisors , appliance intervention is usually indicated . However , the child must want to stop the habit . To achieve success , the child’s cooperation and willingness to work with the dentist is essential . Habits can be responsible for a number of problems . Thumb and finger habits , can cause an anterior open bite , facial movement of the upper incisors , lingual movement of the lower incisors , and constriction of the maxillary arch.