A cephalometric study on changes in hyoid bone, tongue and upper airway space according to skeletal change in persons with mandible prognathism after orthognathic surgery

Kim, Kyung Wook; Choung, Jong Il; Kim, Chul Hwan

Abstract

Orthognathic surgical procedures are designed to correct congenital or acquired dentofacial deformities, achieve cosmetic improvement of the face and dentition. Several investigations have shown that orthognathic surgery influences both the soft and hard tissues in the maxillofacial region, including the tongue and pharyngeal airway. This study was performed to evaluate the changes in the hyoid bone and tongue position, and pharyngeal airway space after mandibular setback osteotomy in 25 patients with mandibular prognathism by means of cephalometric analysis. Lateral cephalograms were obtained at pre-operation(T0) and 2-4days later the operation(T1) and 6 months post-operative follow-up(T2). In this study, we found that there were significant changes in position of hyoid bone and tongue and width of pharyngeal airway space after mandibular setback osteotomy(T1) in persons with mandible prognathism. and except of hyoid bone this change remained stable at 6 months follow up(T2). Especially in analysis with the amount of mandible set back; The cases where the amount of mandible set back was 6~7mm under, there was no significant change in hyoid bone movement. But above 6~7mm there was significant change. The cases where the amount of mandible set back was 11~12mm under, there was no significant change in tongue and pharyngeal airway space width. But above 11~12mm, there was significant change.