If the intensity of the habit persists or increases and adverse dental and skeletal changes are noted beyond age 4 years, corrective measures may be needed to avoid undesirable occlusal problems. By the age of 6to 7 years, estimates indicate that approximately 10% to 15% of children have a persistent digit-sucking habit that runs the gamut from incidental sucking at bedtime to pronounced habits that seems to be almost constant. Almost all authorities recognize that persistent digit-sucking habits extending into the incisor transition period can cause a malocclusion or aggravate an already existing one. Pressure generated from the habit can produce changes in the anterior segments of the dental arches, with labial flaring and protrusive spacing of maxillary anterior teeth and increased overjet. Remodeling of the maxillary alveolar process and vertical displacement of the maxillary anterior teeth can result in an open-bite relationship.