Facial soft tissue profile following bimaxillary orthognathic surgery

To determine the changes in the position and area of nasal and labial soft tissues in adult skeletal Class III patients who underwent bimaxillary orthognathic surgery.

Pretreatment (T1), preoperative (T2), and posttreatment (T3) cephalometric variables and upper-lower lip areas were measured on lateral cephalometric radiographs for 20 individuals (9 male, 11 female; mean age 21.3 years at T1, 22.4 years at T2, and 23.4 years at T3) who had maxillary advancement and mandibular setback. Analysis of variance (ANOVA) and Duncan tests were used to compare the cephalometric and area measurements at the beginning of treatment, and at presurgery and postsurgery, respectively. Paired t-tests were also performed to analyze changes within the periods.

The tip of the nose was affected less with the movement of the underlying skeletal structure (0.25%), while the soft tissue B point (B') moved equally with the skeletal B point. As the maxilla related variables increased due to the forward movement, the upper labial areas decreased. With the backward movement of the mandible, the middle and inferior lower labial areas increased, while the superior lower labial area decreased.

The results of our study suggest that the dramatic improvement in the facial profiles of the bimaxillary surgery patients is primarily related to the backward movement of the mandible and the significant reduction in the superior lower lip area.