A case of severe maxillary hypoplasia in a 21 years old male Thai patient with a complete unilateral cleft of primary
and secondary palates treated by internal distraction osteogenesis for maxillary advancement is presented. Initial evaluation
showed Class III malocclusion with total crossbite and Class III skeletal malrelationship. Two intraoral distractors were
placed following a Le Fort I osteotomy. A maxillary advancement of 8 mms was obtained with 1 mm overjet. Following
distraction, Class III elastics were used to increase the overjet until an overjet of 3 mms was obtained. Both acceptable skeletal
and soft tissue relationships and satisfactory occlusion have been produced. After 20 months of postoperative follow-up, the
occlusal result is stable and skeletal relapse can not be detected.

Keywords: Distraction osteogenesis, Maxillary hypoplasia, Cleft lip and palate, Intraoral distraction device