[Three-dimensional study of facial soft tissue changes in patients with skeletal Class Ⅲ malocclusion before and after orthognathic surgery].

OBJECTIVE

To investigate the changes of facial soft tissue before and after orthognathic surgery in patients with skeletal Class Ⅲ malocclusion.

METHODS

Between August 2016 and April 2017, 30 patients with skeletal Class Ⅲ malocclusion who underwent maxillary LeFort Ⅰ osteotomy and sagittal split mandible osteotomy were selected as study subjects. Among them, 11 were male and 19 were female with an average age of 22.6 years (range, 18-35 years). Full head CT scan and facial soft tissue three-dimensional image scan were performed within 2 weeks before surgery and at 6 months after surgery. A three-dimensional facial image model was established using Artec Studio 11.0 and CMF Proplan 3.0 software to analyze the facial soft tissue changes before and after surgery. The soft tissue anatomical landmarks in each area of the face were measured and compared before and after surgery.

RESULTS

The area of facial soft tissue change after surgery was the maxillary nose and the lower jaw area, and the two sides did not exceed the vertical boundary of the outer canthus. After surgery, the horizontal points of bilateral alar bases and bilateral cheeks changed significantly ( P<0.05). The sagittal points of subnasale, pronasale, bilateral alar bases, upper lip margin significantly forwarded ( P<0.05); the sagittal points of the bilateral cheilions, lower lip margin, midpoint of chin-lip groove, pogonion, and menton significantly backwarded ( P<0.05). The vertical points of the upper lip margin, bilateral cheilions, lower lip margin, bilateral cheeks, and bilateral inner canthus points significantly descended ( P<0.05), and the vertical point of the menton significantly elevated ( P<0.05). After surgery, the nasal column was significantly shortened, the upper lip got longer and the alar base widened when compared with those before surgery ( P<0.05).

CONCLUSION

The overall change of face after double jaw surgery is shorter and fuller, and the mandible of facial soft tissue change is larger than that of maxillary, which suggests that the postoperative facial changes should be taken into account in the surgical design.