Prospective assessment of maxillary advancement effects: maxillary incisor exposure, and upper lip and nasal changes.

ABSTRACT

INTRODUCTION: Our aim was to assess changes in maxillary incisor exposure, and upper lip and nasal soft tissues with maxillary advancement with or without impaction, accounting for the use of cinch sutures and VY closures. METHODS: This was a prospective study of 41 consecutive patients undergoing maxillary advancement with or without impaction. Lateral cephalometric radiographs and clinical measurements were taken preoperatively and up to 6 months postoperatively by 1 examiner. RESULTS: Thirty-one patients (19 female, 12 male) with a mean age of 25.5 years (range, 16.9-49.9 years) completed the study. Twenty-six received bimaxillary surgery. Fifteen had simple closures, 6 had cinch sutures, and 10 had alar base cinch and VY closures. The mean amounts of maxillary advancement and impaction were 3.34 and 1.6 mm, respectively. Soft tissues followed increasingly more closely the hard tissue advancement from pronasale to stomion superius. Mean maxillary incisor exposure increased at rest (0.5 mm) and on smiling (1.0 mm). The nasolabial angle increased (1.88°) because of columella upturning. Alar base width (3.09 mm) significantly increased. CONCLUSIONS: Soft to hard tissue horizontal ratios increased progressively from pronasale to stomion superius. Alar base cinch and VY closures increased these further. Maxillary incisor display changes were partly explained by presurgical upper lip thickness and soft tissue manipulation. Nasolabial angle increased, and cinch sutures seemed to increase this further. Alar base width increased significantly, and the cinch sutures did not significantly limit this.