The effect of maxillary advancement and impaction on the upper airway after bimaxillary surgery to correct Class III malocclusion.

AIM

The aim of this study was to evaluate the upper airway changes after simultaneous maxillary advancement/impaction and mandibular setback in skeletal Class III malocclusion.

METHODS

The subjects included 76 patients whose treatment included 1-piece LeFort I and bilateral sagittal split osteotomies. Lateral cephalograms were taken before surgery and 2 months and 3 years postoperatively. In order to analyze the effect of maxillary repositioning, the material was divided into subgroups according to whether the maxillary impaction and advancement were clinically significant (≥2 mm) or not.

RESULTS

Advancement of the maxilla with or without impaction resulted in a significant long-term increase (P <0.001) in airway dimension at the nasopharyngeal level (13%-21% increase). At the oropharyngeal and retrolingual levels, a decrease took place but was significant (P <0.05) only at the oropharyngeal level when the maxilla was not impacted. When the maxilla was not advanced, there was no significant change, except at the hypopharyngeal level (12% decrease) (P <0.01).

CONCLUSIONS

Clinically significant advancement (≥2 mm) of the maxilla significantly increased the airway dimension at the nasopharyngeal level and to some extent compensated for the effect of mandibular setback at the hypopharyngeal level.