Evaluation of facial soft tissue changes with optical surface scan after surgical correction of Class III deformities

To evaluate the soft tissue changes after correction of Class III dentoskeletal deformity with orthognathic surgery using the optical surface scanner as a 3-dimensional imaging tool and thin-plate splines as a morphometric analysis.

Forty-six patients with Class III dentoskeletal relationship who underwent a bimaxillary orthognathic surgical procedure involving advancement of the maxilla and mandibular setback to correct the deformity and create a Class I dentoskeletal relationship were included. Optical surface scans (lasergraphs) were obtained from all patients preoperatively and 6 months postoperatively. They were evaluated for the soft tissue changes 3-dimensionally and on the profile line. The cephalographs taken pre- and postoperatively were digitized and evaluated using the CogSoft digitizing software (Consultant Orthodontists Group Software, Bristol, United Kingdom) to confirm whether the preoperative surgical plan was applied.

The soft tissue change in different areas of the face ranged from 30% on the nasal tip to 80% on subnasale and from 50% on subcomissural region corresponding to lateral parts of the mandibular body to 100% on the pogonion. The direction of soft tissue movement was not solely forwards and backwards on a horizontal plane but had upward and downward vectors.

The soft tissue changes following orthognathic surgery depend on various factors; hence it can be difficult to predict. However, there is a general trend as discussed in this study for the direction and amounts of facial soft tissue changes in the middle and lower facial thirds.