Dental consequences of pterygomaxillary dysjunction during fronto-facial monobloc advancement with internal distraction for Crouzon syndrome

Crouzon syndrome is a syndromic faciocraniosynostosis that can be associated with severe fronto-facial retrusion leading to major functional impairments: extreme exorbitism may be vision-threatening and severe respiration impairment can be life-threatening. The procedure of choice for the primary correction of this retrusion is fronto-facial monobloc advancement (FFMBA) with internal or external distraction. FFMBA involves pterygomaxillary dysjunction (PMD), using either a superior or an intra-oral approach. This step is at risk of damaging the germs of the decidual and permanent molars. Here we considered a series of 15 patients with Crouzon syndrome who benefited from FFMBA performed by the same surgeon, using a superior approach through the infra-temporal fossa for PMD. Based on pre-operative, early post-operative and late post-operative CT-scans, we recorded missing teeth, morphological dental anomalies and the Nolla stage for the first and second permanent maxillary molars. We showed that early FFMBA has significant dental consequences, and that these dental effects are correlated with an early age at surgery. Although the indications of early FFMBA in Crouzon syndrome with severe functional repercussions are not questionable, our results should be compared to dental outcomes of FFMBA performed with an intra-oral PMD.