RESUMO
Pycnodysostosis is an extremely rare genetic osteosclerosis caused by cathepsin K deficiency. It is a human autosomal recessive genetic disorder characterized mainly by osteosclerosis of the skeleton due to decreased bone turnover. It is characterized by short stature, brachycephaly, short and stubby fingers, open cranial sutures and fontanelle, and diffuse osteosclerosis. Multiple fractures of the long bones and osteomyelitis of the jaw are frequent complications. The authors describe an 18-year-old girl with a clinical and radiological diagnosis of pycnodysostosis and the ortho-surgical treatment undertaken. Bimaxillary orthognathic surgery was carried out using rigid fixation and bone grafts. The authors recommend bimaxillary orthognathic surgery as a choice for treating the dentofacial deformities of pycnodysostosis, emphasizing the good and stable results obtained in terms of facial aesthetics and occlusion.