Retrognathic maxilla in "Habsburg jaw". Skeletofacial analysis of Joanna of Austria (1547-1578)

OBJECTIVE: To evaluate the dentoskeletal features of the "Habsburg jaw" by analyzing the skull of Joanna of Austria. MATERIALS AND METHODS: The skull, the panoramic radiograph, and the lateral cephalogram of Joanna of Austria were analyzed. The cephalometric values of Joanna were compared to cephalometric standards for adult female subjects. RESULTS: The analysis of the dentition on the dry skull and on the panoramic radiograph showed a generalized horizontal alveolar bone resorption with severe bone loss that was interpreted as a sign of severe periodontal disease with respect to the young age (31 years). The cephalometric analysis revealed the presence of a skeletal Class III disharmony associated with maxillary retrusion and normal sagittal position of the mandible. The maxilla exhibited a reduction in the sagittal dimension while the mandible presented with increased dimensions both in total mandibular length (Co-Gn) and in the mandibular body (Go-Gn). The skeletal open bite contributed to the lack of mandibular protrusion though in presence of increased mandibular sagittal dimensions. CONCLUSION: Joanna of Austria appeared to be affected by a peculiar type of "Habsburg jaw" as the Class III skeletal disharmony was due to a retrognathic maxilla rather than to a prognathic mandible.