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

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.

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Hard and Soft Tissue Changes in Patients with Borderline Class III Malocclusion after Maxillary Advancement or Mandibular Setback Surgery: A Cross-Sectional Study

Dental Oral Biology and Craniofacial Research ◽

10.31487/j.dobcr.2020.01.08 ◽

2020 ◽

pp. 1-6

Author(s):

Abdolreza Jamilian ◽

Ali Fateh ◽

Ludovica Nucci ◽

Abdolreza Jamilian ◽

Fabrizia d’Apuzzo ◽

...

Keyword(s):

Soft Tissue ◽

Cross Sectional Study ◽

Distributed Data ◽

Class Iii ◽

Class Iii Malocclusion ◽

Cross Sectional ◽

Mandibular Setback ◽

Maxillary Advancement ◽

Tissue Changes ◽

Soft Tissue Changes

Background: The primary aim of this study was to assess the esthetic profile and hard and soft tissue changes in patients with borderline class III malocclusion after maxillary advancement or mandibular setback surgery. The secondary aim was also to evaluate the patients’ face attractiveness after different surgical treatment. Materials and Methods: This observational cross-sectional study evaluated 50 patients with borderline class III malocclusion with a mean age of 29 ± 4 years treated from 2014 to 2019. They were divided into two groups based on the type of surgical treatment underwent: 13 patients were treated with mandibular setback (4 males, 9 females), and 37 patients with maxillary advancement (16 males, 21 females). Hard and soft tissue parameters were measured pre and postoperative evaluation. Frontal and profile photographs of these patients were judged by 15 orthodontists, 15 oral and maxillofacial surgeons, and 15 laypeople before and after surgery. The most and the least attractive profiles were scored 10 and 0, respectively. T-test was used to analyze normally distributed data while Mann-Whitney test for non-normally distributed data. The Kruskal-Wallis test was used to compare the esthetic judgement between the three groups of observers. Pairwise comparisons were carried out using the Mann-Whitney test. Results: Nasolabial angle, SNA, U1/NA (°), U1/NA (mm), L1/NB (°) and L1/NB (mm) were significantly different between the two groups p<0.04, p<0.001, p<0.001, p<0.005, p<0.07, p<0.08, p<0.01 respectively Orthodontists, oral and maxillofacial surgeons, and laypeople all gave a lower score to mandibular setback and higher score to maxillary advancement in terms of facial profile esthetics (P<0.001). Conclusion: Some cephalometric parameters were significantly different between the two groups. The maxillary advancement seemed to provide better results in facial profile esthetics than mandibular setback for patients with borderline class III malocclusion.

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