Changes in tongue and hyoid bone positions following anterior mandibular subapical osteotomy in patients with Class III malocclusion.

In a sample of 28 Chinese adults (aged 24.2 +/- 3.1 years) who underwent anterior mandibular subapical osteotomy for the correction of Class III malocclusions, the interaction among intermaxillary space, tongue position, and hyoid bone variables were quantified retrospectively using pretreatment and posttreatment lateral cephalograms. Lateral cephalograms taken at the early (5 to 7 days) postsurgical period showed that the intermaxillary space decreased. The hyoid bone also moved inferiorly, while the tongue was displaced posteriorly and superiorly. The late (2 years) postsurgical lateral cephalograms showed that the hyoid bone and tongue position normalized to the pretreatment positions. These changes demonstrate the ability of the hyoid bone and tongue structures to adapt to changes in the intermaxillary space following osteotomy.