scholarly journals Three-dimensional Analysis of Mandible Ramus Morphology and Transverse Stability After Intraoral Vertical Ramus Osteotomy

2021 ◽  
Author(s):  
Luo Huang ◽  
Shan Tang ◽  
Jing Yan ◽  
Yaoran Liu ◽  
ZhengGuo Piao
Keyword(s):  
Three Dimensional ◽  
Reference Points ◽  
Class Iii ◽  
Mandibular Ramus ◽  
Skeletal Class ◽  
Computed Tomography Images ◽  
Postoperative Changes ◽  
Transverse Stability ◽  
Intraoral Vertical Ramus Osteotomy ◽  
Vertical Ramus Osteotomy

Abstract Objectives: The purpose of this study was to investigate short- and long-term postoperative changes of both morphology and transverse stability in mandibular ramus after intraoral vertical ramus osteotomy (IVRO) in patients with jaw deformity using three-dimensional (3D) orthognathic surgery planning treatment software for measurement of distances and angles.Study Design: This retrospective study included consecutive patients with skeletal Class III malocclusion who had undergone intraoral vertical ramus osteotomy and computed tomography images before (T0), immediately after (T1), and one year after (T2) surgery. Reference points, reference lines and evaluation items were designated on the reconstructed 3D surface models to measure distances, angles and volume. The average values at T0, T1, T2 and time-dependent changes in variables were obtained.Results: After surgery, the condylar length, ramal height, mandibular body length and mandibular ramus volume were significantly decreased (P < .01), while clinically insignificant change was observed from T1 to T2. The angular length was increased immediately after surgery (P < .05), but it was decreased 1 year after surgery (P < .05). Lateral ramal inclination showed significant increase after surgery (P < .05) and maintained at T2.Conclusion: Changes in the morphology of the mandibular ramus caused by IVRO do not obviously bring negative effect on facial appearance. Furthermore, despite position and angle of mandibular ramus changed after IVRO, good transverse stability was observed postoperatively. Therefore, IVRO technique can be safely used without compromising esthetic results.

scholarly journals Computer-Aided Planning in Orthognathic Surgery: A Comparative Study with the Establishment of Burstone Analysis-Derived 3D Norms

2019 ◽  
Vol 8 (12) ◽  
pp. 2106 ◽  
Author(s):  
Cheng-Ting Ho ◽  
Rafael Denadai ◽  
Hsin-Chih Lai ◽  
Lun-Jou Lo ◽  
Hsiu-Hsia Lin
Keyword(s):  
Orthognathic Surgery ◽  
Three Dimensional ◽  
Computer Assisted ◽  
Class Iii ◽  
Facial Soft Tissue ◽  
Skeletal Class ◽  
Nasolabial Angle ◽  
Normal Occlusion ◽  
Computer Aided ◽  
Cephalometric Measurements

Three-dimensional (3D) computer-aided simulation has revolutionized orthognathic surgery treatment, but scarce 3D cephalometric norms have been defined to date. The purposes of this study were to (1) establish a normative database of 3D Burstone cephalometric measurements for adult male and female Chinese in Taiwan, (2) compare this 3D norm dataset with the two-dimensional (2D) Burstone norms from Caucasian and Singaporean Chinese populations, and (3) apply these 3D norms to assess the outcome of a computer-aided simulation of orthognathic surgery. Three-dimensional Burstone cephalometric analysis was performed on 3D digital craniofacial image models generated from cone-beam computed tomography datasets of 60 adult Taiwanese Chinese individuals with normal occlusion and balanced facial profile. Three-dimensional Burstone analysis was performed on 3D image datasets from patients with skeletal Class III pattern (n = 30) with prior computer-aided simulation. Three-dimensional Burstone cephalometric measurements showed that Taiwanese Chinese males had significantly (p < 0.05) larger anterior and posterior facial heights, maxillary length, and mandibular ramus height than females, with no significant (p > 0.05) difference for facial soft-tissue parameters. The 3D norm dataset revealed Taiwanese Chinese-specific facial characteristics, with Taiwanese presenting (p < 0.05) a more convex profile, protrusive maxillary apical bases, protruding mandible, protruding upper and lower lips, and a shorter maxillary length and lower facial height than Caucasians. Taiwanese had significantly (p < 0.05) larger maxillary projection, vertical height ratio, lower face throat angle, nasolabial angle, and upper lip protrusion than Singaporean Chinese. No significant (p > 0.05) difference was observed between 3D norms and computer-aided simulation-derived 3D patient images for horizontal skeletal, vertical skeletal, and dental measurements, with the exception of two dental parameters (p < 0.05). This study contributes to literature by providing gender- and ethnic-specific 3D Burstone cephalometric norms, which can assist in the multidisciplinary-based delivery of orthodontic surgical care for Taiwanese Chinese individuals worldwide, including orthodontic management, computer-assisted simulation, and outcome assessment.

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