Thumb or Finger Sucking: Finger and thumb sucking is common in infancy and early childhood and, in the majority of cases, is spontaneously discontinued by about 5 years of age. In a minority of cases, however, the habit may continue for several more years, even into adolescence and beyond. The habit may produce deformity both of the finger/thumb and the dental occlusion.
Tongue Thrusting: Tongue thrusting, abnormal tongue position, and deviation from the normal swallowing pattern, tongue thrust is normal in infants until approximately the age of six months. If a child suffers from tongue thrusting, this continuous pressure tends to force the teeth out of alignment. Many children who have tongue thrust lead to open bites, the force of the tongue against the teeth is an important factor in contributing to “bad bite” (malocclusion).
Mouth Breathing: Mouth breathing has been classified according to etiology into three groups: obstructive, habitual, and anatomic. The nasal airway may be compromised partially or completely obstructed. Such individuals may find it difficult or impossible to breathe through their noses alone. In about 85% of cases, mouth breathing is an adaptation to nasal obstruction.