Comparison Between Treacher Collins Syndrome and Pierre Robin Sequence: A Cephalometric Study.

The aim of this study was to compare the dentoskeletal pattern of Treacher Collins syndrome (TCS) and nonsyndromic Pierre Robin sequence (PRS). Retrospective. Single center. Eighteen patients diagnosed with TCS (Group TCS) or PRS (Group PRS) in rehabilitation treatment at a single center. Group TCS was composed of 9 patients (4 male, 5 female) with a mean age of 12.9 years (standard deviation = 4.8). Group PRS was composed of 9 patients paired by age and sex with group TCS. Cone beam computed tomography-derived cephalometric images taken before the orthodontic or the orthodontic-surgical treatment were analyzed using Dolphin Imaging (Dolphin Imaging 11.0 & Management Solutions). Variables evaluating the cranial base, the maxillary and mandibular skeletal components, maxillomandibular relationship, the vertical components and the dentoalveolar region were measured. Intergroup comparisons were performed using Intergroup differences in the mandible size and growth pattern were observed. Group TCS showed a smaller mandibular length (Co-Go, Co-Gn) and a higher palatal plane (SN-Palatal Plane) and mandibular plane angles (SN-Go.Gn) compared to group PRS. No differences between TCS and PRS were observed for the sagittal position of the maxilla, maxillomandibular relationship, and dental components. Treacher Collins syndrome presented a decreased mandible and a more severe vertical growth pattern compared to PRS.