[8-1]_(1~9) Analysis of 3-dimensional Changes of The Facial Hard and Soft Tissues After 2-jaw Surger

Analysis of 3-dimensional Changes of The Facial Hard and Soft Tissues After 2-jaw Surgery in Mandibular Prognathic Patients Using 3D CBCT and White Light 3D Scanner

Ji-Sun Yang, Ki-Ho Park

Department of Orthodontics, School of Dentistry, Kyung Hee University, Seoul, Korea

Purpose: The purpose of this study was to analyze three-dimensional changes of the facial hard and soft tissues after 2-jaw surgery in mandibular prognathic patients using 3D CBCT and white light 3D scanner.

Materials & Methods: Thirteen patients with mandibular prognathism who underwent Le fort I osteotomy and BSSRO surgery were selected. CBCT and 3D facial scans were performed. After superimposing CBCT images and 3D scan images before and after surgery respectively, the x, y, z coordinates and length measurements of 11 hard tissue landmarks and 16 soft tissue landmarks were obtained using Morpheus analysis program.

Results: In the transverse direction, the landmarks of the soft tissues moved in the direction of resolving asymmetry and the amount of movement increased downward but there was no statistical significance. In the bilateral landmarks, the deviated side moved more than the contralateral side, but there was no statistical significance. Nose width increased and lip width decreased significantly. In the vertical direction, the jaw-related landmarks moved upward and the lower facial height decreased, which was statistically significant. In the anteroposterior direction, the landmarks of the nose and upper lip moved forward and the landmarks of the lower lip and jaw moved backwards significantly. The range of soft tissue hard tissue migration rate was 0.3-1.7.

Conclusion: Three-dimensional evaluation of hard and soft tissues using CBCT and facial scans allowed more accurate analysis of soft and hard tissue changes after 2-jaw surgery in mandibular prognathism. It is expected to improve the treatment results by accurately predicting the amount of facial soft tissue changes after 2-jaw surgery.

Key words: Soft tissue change, Mandibular setback surgery, Class III, CBCT, Structured light scanner

Korean J Lingual Orthod 2019;8(1):1-9