Soft-tissue changes after maxillomandibular advancement surgery assessed with cone-beam computed tomography

Abstract

The purpose of this study was to quantify anteroposterior and transverse facial soft-tissue changes with respect to underlying skeletal movements after maxillomandibular advancements by using cone-beam computed tomography. Thirty white patients were treated by maxillomandibular advancements after LeFort I osteotomies and bilateral sagittal split osteotomies. The patients were scanned by using cone-beam computed tomography within 1 week before the surgery, within 1 week after the surgery, and a minimum of 8 weeks postsurgery. We measured the differences between the first and last images and calculated ratios for anteroposterior and transverse soft-to-hard tissue movements. Changes in the greatest interalar width were also measured. There was a statistically significant difference in the greatest interalar width change between patients receiving maxillary advancements greater than 4 mm and those having advancements less than or equal to 4 mm (P <0.023). Mean ratios of anteroposterior soft-to-hard tissue movements were 84.9% +/- 38.0% in the malar region, 96.1% +/- 15.5% in the chin, and 101.1% +/- 27.3% in the subcommissural region. Mean ratios of transverse soft-to-hard tissue movements were 39.4% +/- 19.7% in the malar region and 82.5% +/- 56.7% in the subcommissural region. The amount of maxillary advancement most likely plays a role in the postsurgical increase in interalar width. In addition, facial soft tissues appear to respond more to anterior movement of the jaws than to an increase in transverse dimensions after maxillomandibular advancements.