Nasolabial soft tissue changes associated with posterior maxillary movement following anterior segmental osteotomy in skeletal Class II patients: A case series

Objective

This study investigated the relationship between the external nasal morphology and hard tissue movement in patients who underwent anterior segmental maxillary osteotomy (ASMO) to correct maxillary protrusion correction.

Methods

The study enroled patients with an overjet ≥ 5 mm, and an ANB ≥ 2° who underwent ASMO with or without Le Fort I osteotomy. Linear and angular measurements were performed on computed tomography images obtained preoperatively and one year post-surgery.

Results

The movement of the maxilla at U1 was 6.7 ± 2.9 mm backward and 1.9 ± 2.0 mm upward. Tooth axis inclination of U1 (∠U1 to FH) increased 5.5 ± 6.1°. The nasolabial angle significantly increased from 90.0 ± 16.8° to 101.0 ± 13.2°. No significant differences were observed in alar base width or nasal tip angles. The change of ∠U1 to FH and the backward movement of U1 were relevant factors influencing the change of nasolabial angle.

Conclusions

This study provides insights into the relationship between external nasal morphology and posterior movement of the anterior maxillary segment after ASMO surgery. These findings are significant for predicting post-operative patient profiles.