Three-dimensional evaluation of soft tissue changes after mandibular setback surgery in class III malocclusion patients according to extent of mandibular setback, vertical skeletal pattern, and genioplasty Minji Kim, DDS, MSD, PhD, a Dong-Yul Lee, DDS, MSD, PhD, b Yong-Kyu Lim, DDS, MSD, PhD, b and Seung-Hak Baek, DDS, MSD, PhD, c Seoul, Korea KOREA UNIVERSITY AND SEOUL NATIONAL UNIVERSITY Objective. To investigate the 3-dimensional (3D) changes in the soft tissue after mandibular setback surgery (MSS). Study design. Thirty-three skeletal class III malocclusion (SCIII) patients treated with MSS (bilateral sagittal split ramus osteotomy) were subdivided according to extent of MSS, vertical skeletal pattern (VP), and vertical-reduction genioplasty. Lateral cephalograms and 3D facial scan images were taken before and 6 months after surgery. Linear and angular variables were measured with Rapidform 2006 (Inus Technology). Results. After MSS, there were significant increases in the upper lip length and decreases in the lower lip length in the large setback, hypodivergent, and genioplasty groups. The mentolabial fold deepened less in the genioplasty group than in other groups. Although there was no skeletal advancement of the maxilla, the soft tissue convexity in the paranasal area increased more in the hyperdivergent group than in the hypodivergent group after MSS. Conclusion. The extent of MSS, VP, and genioplasty could be used as guidelines for 1- and 2-jaw surgeries in SCIII borderline cases. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;109:e20-e32) Improvement in facial esthetics is one of the most important goals of orthodontic treatment and orthog- nathic surgery. Traditionally, cephalometric analysis has been used to evaluate and predict changes in facial profile after orthodontic treatment and orthognathic surgery. 1-6 However, this conventional 2-dimensional (2D) method can only evaluate the soft tissues of the midsagittal area. 2,3 To analyze and evaluate the soft tissues in the paranasal, zygomatic, cheek, and other facial areas, 3-dimensional (3D) imaging methods such as 3D computerized tomography (CT) 7-9 and 3D facial scan images (3D-FSI) 10-15 are needed. Furthermore, several studies 16,17 have reported that 3D methods are more accurate than 2D methods. The majority of Asian patients seeking orthodontic treatment and orthognathic surgery are class III maloc- clusion patients. 18,19 Clinicians sometimes experience good improvement in facial esthetics in the midface area with the mandibular setback surgery (MSS) only in the class III malocclusion borderline cases (Fig. 1). 19 The purpose of the present study was to investigate, using 3D-FSI, changes in the soft tissue after mandibular setback surgery. Our hypotheses were that soft tissue changes due to mandibular setback surgery would be seen not only in the upper and lower lips, but also in other areas remote to the midsagittal area, such as the zygomatic, cheek, and paranasal areas, and that these changes would be influenced by the extent of mandibular setback, the vertical skeletal pattern, and genioplasty. MATERIALS AND METHODS Thirty-three skeletal class III malocclusion patients (11 male and 22 female; mean age 25.23  7.44 years; SNA 80.48  3.64°; SNB 82.91  4.07°; Wits ap- praisal -11.20  4.14 mm; A to N perpendicular -1.10  3.17 mm; Pog to N perpendicular 4.08  7.49 mm; SN-GoGn 35.27  6.21°; 3 mm facial asym- metry at the soft tissue pogonion point) who had un- dergone mandibular setback surgery (bilateral sagittal split ramus osteotomy, average amount of mandibular setback 8.16  3.74 mm at point B) by a single surgeon were included in this study. Patients were subdivided according to the extent of MSS, the vertical skeletal pattern, and vertical-reduc- tion genioplasty (Table I). Approval for this study was granted by the Institutional Review Board of Korea University Medical Center (IRB no. GR0791). a Fellow, Department of Dentistry, College of Medicine, Korea Uni- versity. b Professor, Department of Dentistry, College of Medicine, Korea University. c Associate Professor, Department of Orthodontics, School of Den- tistry, Dental Research Institute, Seoul National University. Received for publication Oct 16, 2009; returned for revision Dec 23, 2009; accepted for publication Jan 3, 2010. 1079-2104/$ - see front matter © 2010 Mosby, Inc. All rights reserved. doi:10.1016/j.tripleo.2010.01.002 e20