Three-dimensional analysis of lip soft tissue changes and related jaw changes in patients with skeletal class III malocclusion and facial asymmetry

Abstract

OBJECTIVE: To investigate three-dimensional soft tissue changes of lips and related jaw changes in patients with skeletal class III malocclusion and facial asymmetry using cone-beam computerized tomography (CBCT). METHOD: This study included 46 CBCT scans of patients with aforementioned character before (T1) and 6–12 months after orthognathic surgery (T2). Subjects were divided into 2 groups according to two types of orthognathic surgery namely, the one-jaw surgery group who underwent bilateral sagittal splint ramus osteotomy (BSSRO) and the two-jaw surgery group who underwent Le Fort I osteotomy and BSSRO. Mimics 19.0 software are used for model reconstruction, landmark location and three-dimensional cephalometric analysis. Descriptive statistics and correlation analyses are used to investigate jaw hard tissue and lip soft tissue changes. RESULTS: In one-jaw group, the mandible shows changes in contour and position (p < 0.05), and the surgery causes changes of lip structure on the deviated side. While in two-jaw group, jaws only show changes in spatial position, and surgery changes contour of bilateral lips and nasolabial angle (p < 0.05). At the same time, lip symmetry increases significantly in both groups postoperatively. CONCLUSIONS: Orthognathic surgery can improve lip aesthetics in patients with skeletal class III malocclusion and facial asymmetry. However, changes induced by two surgical approaches are different. Surgeons should have a clear acquaintance with this difference to deal with different situations.

Three-Dimensional Change of Lip after Two-Jaw Surgery in Facial Asymmetry Using Facial Scanner

“…Regarding changes in the coronal plane of the lip, as Ch-D moved toward the MSP, the difference in the distance from the MSP to the Ch-D and Ch-ND significantly decreased post-surgery, which is consistent with the findings of Kwon et al [8]. As a result of these differential movements of Ch-D/ND, the lip width was reduced, which is consistent with the findings reported by Xu et al [27]. Assuming that transverse lip asymmetry is the difference in the distance from the MSP to the Ch-D and Ch-ND in the transverse axis, the difference was significantly reduced after surgery, indicating that the asymmetry had improved (Table 4).…”

Treatment outcome and long-term stability of orthognathic surgery for facial asymmetry: A systematic review and meta-analysis

“…Supplementary Table 3 summarizes the NOS results. Most of the studies were assessed as moderate quality, 12 - 48 while a few were assessed as high quality. 14 , 49 - 62 The studies were classified as high quality when the comparability of cohorts was appropriately addressed based on the study design or analysis.…”

“…In a comprehensive review involving 44 studies, 12 - 43 , 49 - 60 77 outcome indicators were analyzed to assess skeletal symmetry before and after orthognathic surgery. The SMDs of skeletal symmetry according to one- and two-jaw surgery are shown in Figure 2 , with descriptions of the study groups and outcome variables in Table 3 .…”

Effect of socioeconomic and malocclusion‐related factors on duration of orthodontic treatment by fixed appliance: A retrospective study

“…1 Clinically, malocclusion is characterized by changes in the shape, the position of teeth, number of teeth, dentition spacing, dental health and facial aesthetic problems, resulting in issues such as personality development disorders and psychological disorders. 2,3 Often, doctors are not able to fully consider patients' expectations and opinions. Rather, their treatment decisions are made based on their own clinical experience and expertise; therefore, the treatment is unable to fully meet patient expectations.…”

“…Malocclusion is influenced by various factors including congenital genetic and/or acquired environmental aspects 1 . Clinically, malocclusion is characterized by changes in the shape, the position of teeth, number of teeth, dentition spacing, dental health and facial aesthetic problems, resulting in issues such as personality development disorders and psychological disorders 2,3 . Often, doctors are not able to fully consider patients' expectations and opinions.…”