Longitudinal dento-skeletal changes in UCLP patients following maxillary distraction osteogenesis using RED system

Longitudinal dento-skeletal changes in unilateral cleft lip and palate (UCLP) patients following maxillary distraction osteogenesis using the rigid external distraction device (RED) were analyzed. Twelve Japanese non-syndromic UCLP patients who underwent maxillary distraction at the mean age of 16.4 years were used as subjects. Serial sets of lateral cephalograms, taken at 4 stages: 1) before osteotomy, 2) immediately after distraction, 3) 6 months and 4) 12 months post-osteotomy, were analyzed. Statistical analyses, including a paired t test, Pearson correlation analysis and stepwise linear regression analysis, were performed to distill characteristic dento-skeletal changes. In accordance with maxillary advancement, significant amounts of up-forward movement of the nasal bone, mandibular rotation and maxillary dental changes were observed. Maxillary dental changes were significantly related to the amount of mandibular rotation and force system of maxillary traction. Significant dento-skeletal relapse was found to occur during the 0-to-6-month follow-up period, but not in the 6-to-12-month follow-up period. Maxillary relapse was significantly related to the amount of maxillary advancement and severity of pre-surgical maxillary hypoplasia, while mandibular relapse was significantly related to maxillary dento-skeletal relapse. Successful clinical application of this procedure therefore requires consideration of both the surrounding dento-skeletal changes and the traction force system.