Maxillary Protraction: Different Effects on Facial Morphology in Unilateral and Bilateral Cleft Lip and Palate Patients

Since 1977 patients with anterior/posterior crossbites in the care of the Bergen CLP team have undergone an interceptive orthopedic protraction phase during the deciduous and mixed dentition period. Eighty-seven cases with complete clefts (63 unilateral and 24 bilateral) displaying anterior crossbite (negative overjet) were treated to normal occlusion. A fixed quad-helix appliance was used in combination with a facial mask. In the unilateral complete cleft lip and palate (UCLP) group, mean age at start of treatment was 6 years 10 months and mean duration was 12 months. In the bilateral complete cleft lip and palate (BCLP) group, mean age at start of treatment was 7 years and mean duration 15 months. The protraction force was 700 g. The sagittal changes during protraction in the UCLP and BCLP groups were compared, and related to the growth changes in a group of noncleft children at the same age. Dentofacial treatment effect was different in the UCLP and BCLP groups. Significant increase of maxillary prognathism (angle s-n-ss) was found only in the UCLP group, whereas the treatment effect in the BCLP group was mainly dentoalveolar. However, after protraction there was no longer a significant difference in maxillary prognathism between the two CLP groups, and the sagittal position of the upper molars was normalized in both groups. The upper incisors remained retroclined in both groups, significantly more in the BCLP group. Increase of the upper facial height (n-sp”) and clockwise rotation of the occlusal line were significantly greater in the BCLP group. The computerized occlusal line was unsuitable as a reference standard for the evaluation of sagittal dentofacial treatment changes when the occlusal line was rotated during treatment.