Orthodontic-surgical correction with a bilateral mandibular ramus sagittal osteotomy of a skeletal Class III maloclussion

Abstract Objective: To quantify the changes in the nose after bimaxillary surgery to correct skeletal Class III malocclusion and to test the hypothesis that there is no change in the nasal width following bimaxillary surgical correction of skeletal Class III when a nasal cinch is properly used. Materials and Methods: Sixty-five adult Korean skeletal Class III patients who had received maxillary advancement/impaction and mandibular set-back surgery in conjunction with an alar base cinch suture were evaluated. The anthropometric variables of the nasal region were measured directly on the soft-tissue surface before and 6 months after surgery. Results: After surgery, the alar width and alar base width had increased significantly (P < .001), while the nasal tip projection decreased (P < .001). The nostril morphology also showed widening (P < .001). There was a trend for females with a narrow alar width presurgically to have a larger amount of nasal widening compared with those with a broader alar width (P < .05). Conclusion: There is a high probability of nasal and nostril widening after bimaxillary surgery for skeletal Class III malocclusion in Koreans despite the careful performance of alar cinch suture. Nevertheless, the authors believe that alar cinch suture was positive in limiting the nasal widening to the minimum and would consider routine application during bimaxillary surgery for skeletal Class III especially for female patients with a narrow nose who are susceptible to these changes.

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

10.21203/rs.3.rs-779108/v1 ◽

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.

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