Abstract
Pierre Robin Sequence (PRS) is a birth defect characterized by an abnormally small lower jaw. The aim of this study was to compare the craniofacial morphology of Japanese PRS patients with that of patients with isolated cleft palate (ICP) . Eleven pre-adolescent children with PRS (mean age, 7.0 years ; range, 4.1-11.0 years) and 22 children with ICP (mean age, 7.2 years ; range 5.3-9.1 years) were involved in the study. Measurements were taken from standard lateral cephalometric radiographs. Six of the PRS patients had also undergone longitudinal lateral cephalograms, which allowed us to assess changes that occurred with growth. In PRS patients, the mandible was significantly smaller, more recessive and posteriorly rotated compared to the mandible of ICP patients. The curve of the mandibular baseline in PRS patients had a distinctive shape not seen in ICP cases. The lower sagittal depth of the pharynx was significantly shorter in patients with PRS than in those with ICE In the majority of the longitudinally-assessed PRS patients, the craniofacial characteristics became more pronounced with time. Our findings highlight the necessity for developing new and early orthodontic treatments for PRS, because spontaneous improvement through growth does not appear to be a likely outcome.
