Investigating the postoperative soft tissue changes in different vertical facial divergent patients with mandibular prognathism

• Published in: Journal of dental sciences Vol. 19; no. 3; pp. 1443 - 1451
• Main Authors: Tseng, Yu-Chuan, Wu, Ting-Yu, Lu, Chao-Yu, Chou, Szu-Ting, Lin, Shih-Hsuan, Chen, Chun-Ming
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.07.2024; Association for Dental Sciences of the Republic of China; Elsevier
• Subjects: Advanced Basic Science; Cone-beam computed tomography; Dentistry; Hyperdivergence; Mandibular prognathism; Mandibular setback; Normodivergence; Original; Postoperative soft tissue changes; Hyperdivergence; Normodivergence; Mandibular prognathism; Mandibular setback; Cone-beam computed tomography; Postoperative soft tissue changes
• DOI: 10.1016/j.jds.2024.03.024
• ISSN: 1991-7902

The extent of three-dimensional soft tissue changes in patients with varied facial skeletal patterns following mandibular setback surgery remains unclear. In this study, we aimed to investigate the postoperative changes in soft tissue chin thickness among mandibular prognathism patients, focusing on those presenting different divergence patterns, such as hyperdivergent and normodivergent patients. Cone-beam computed tomography images were obtained from 56 skeletal Class III patients who underwent only mandibular setback. Based on vertical craniofacial skeletal relationship, patients were divided into normodivergent group (27°<SN-MP<37°) and hyperdivergent (SN-MP>37°) group. The three-dimensional displacements of Infradentale (Id), B point (B), and Pogonion (Pog), the soft tissue thickness of Id-Li (Labrale inferius), B-B' (soft tissue B point), and Pog-Pog’ (soft tissue Pog point) were measured. Factors influencing the change in soft tissue thickness were investigated. Preoperative B-B' and Pog-Pog’ thickness were significantly thinner in the hyperdivergent group than normodivergent group. Postoperative changes in B-B' and Pog-Pog’ thickness were significantly larger in the hyperdivergent group than normodivergent group. A significant correlation was found between soft tissue thickness change (B-B' and Pog-Pog’) and the preoperative soft tissue thickness and superior movement (B and Pog). Hyperdivergent patients with skeletal class III have thinner preoperative soft tissue thickness (B-B' and Pog-Pog’) than normodivergent patients in the preoperation. Postoperative changes in B-B' and Pog-Pog’ thickness were significantly larger in the hyperdivergent group than normodivergent group. Postoperative superior movement of B and Pog correlated with postoperative change of soft tissue thickness.