Oral and maxillofacial manifestations of Pycnodysostosis: a summary of clinical, radiological and cephalometric diagnostic criteria. A systematic review.

Pycnodysostosis (PYCD) is a rare osteosclerotic disorder with distinct craniofacial features. Diagnosis remains challenging due to overlap with other skeletal dysplasias. The aim of this systematic review was to identify clinical, radiological, and cephalometric maxillofacial features in PYCD and to evaluate their diagnostic relevance. Following PRISMA and AMSTAR guidelines, a search was conducted in Pubmed, Web of Science and Cochrane Library databases. Studies were included if they reported characteristics of the cranial vault, face, or oral cavity. Of the 345 publications identified, 46 studies comprising a total of 69 patients were included. The cohort consisted of 58 % female and 42 % male patients, with a mean age of 20 years and a consanguinity rate of 38 %. Key diagnostic features included frontal bossing (92 %), unclosed cranial sutures (97 %), sclerotic ossification (90 %), midfacial hypoplasia (100 %), exorbitis (83 %), maxillary sinus hypoplasia (97 %), micrognathia (92 %), severely obtuse gonial angle (100 %), narrow and grooved palate (100-73 %) and severe dental crowding (91 %). The cephalometric analysis, available for 17 patients, revealed maxillary and mandibular retrognathia (p = 9.17e-06 and 7.646e-05), with no predominance skeletal class, facial hyperdivergence (p = 0.047), and cranial base morphology contributing to these dysmorphies (p = 9,31e-04).