Effect of maxillary advancement on the change in the soft tissues after treatment of patients with class III malocclusion.

The aesthetic outcome of treatment has become increasingly important to patients having orthognathic surgery. The aim of this observational cohort study based on clinical records was to evaluate the effect of maxillary advancement on changes to the soft tissues. We studied 53 patients with class III malocclusion (29 women and 24 men, mean (SD) age 28 (11) years). We identified all patients treated between 1 January 2002 and 30 December 2013 who could be monitored postoperatively for 6 months. To study the effect of maxillary advancement on changes to the soft tissue we distinguished between patients who had had less than 6mm, and those with 6mm advancement or more. In those who had had less than 6mm, we found no significant changes in the soft tissue in the region of the nasolabial angle. However, the lip-chin- throat angle (p=0.016), cervical length (p=0.002), lower lip (p=0.007) and upper lip distance (p=0.0001) from the aesthetic line changed significantly. On the other hand, the changes to the soft tissue in the submental and nasolabial regions were significant in patients with 6mm advancement or more, and indicated a clear improvement in the aesthetic outcome of this region. This aesthetic change for the good in the submental and nasolabial regions after maxillary advancement of 6mm or more should be considered when planning treatment, and reduction in the mandibular setback will reduce the risk of development of a double chin.