Cephalometric characteristics and dentofacial abnormalities of pycnodysostosis: report of four cases from Brazil.

Pycnodysostosis (PKND) is a human autosomal recessive genetic disorder characterized mainly by osteosclerosis of the skeleton, severe bone fragility, and short stature. This syndrome usually presents very typical craniofacial deformities, such as beaked nose, micrognathia, hypoplastic midface, open mouth posture, grooved palate, anterior cross-bite, dental crowding, and over-retained deciduous teeth. Early diagnosis and intervention are of the utmost importance. Four cases from the northeast of Brazil are reported including 2 siblings. Features included maxillary retrusion, reduced facial height, open bite, and bone fracture history. Very poor oral hygiene, severe dental caries, and periodontal disease were also present.