A case of Antley-Bixler syndrome with severe skeletal Cl. III malocclusion.

Antley-Bixler syndrome is a disorder characterized by craniosynostosis, midface hypoplasia, choana blockade, and radiohumeral synostosis. However, the features of occlusion remain unclear. In this paper, we report a case of Antley-Bixler syndrome, a 7-year-old boy, from the viewpoint of orthodontics. From lateral cephalometric head film analysis, remarkable retardation of the anterior subcranial base, infraorbitale, and maxilla were notable, as was vertical growth restriction of the maxilla. The choana blockade tendency was also recognized. Moreover, although reverse occlusion was present, a mandibular retrognathic tendency was also present, and a short ramus mandible, remarkable mandibular vertical growth pattern, and skeletal open bite were present. In the dentition, two of the lower incisors were missing, and the present lower incisors were large. Maxillary and mandibular first molars were delayed in eruption. For treatment, the solutions to such remarkable skeletal problems were limited by the insufficiency of recovery of cranial formation after the operation. We planned a non-surgical treatment to expand the maxilla. It will be necessary to continually consider the treatment of his malocclusion as he continues to grow.