• Archives of Plastic Surgery
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• 제50권3호
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• pp.254-263
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• 2023

Background The three-dimensional (3D) evaluation of skeletal stability after orthognathic surgery is a time-consuming and complex procedure. The complexity increases further when evaluating the surgery-first orthognathic approach (SFOA). Herein, we propose and validate a simple time-saving method of 3D analysis using a single software, demonstrating high accuracy and repeatability. Methods This retrospective cohort study included 12 patients with skeletal class 3 malocclusion who underwent bimaxillary surgery without any presurgical orthodontics. Computed tomography (CT)/cone-beam CT images of each patient were obtained at three different time points (preoperation [T0], immediately postoperation [T1], and 1 year after surgery [T2]) and reconstructed into 3D images. After automatic surface-based alignment of the three models based on the anterior cranial base, five easily located anatomical landmarks were defined to each model. A set of angular and linear measurements were automatically calculated and used to define the amount of movement (T1-T0) and the amount of relapse (T2-T1). To evaluate the reproducibility, two independent observers processed all the cases, One of them repeated the steps after 2 weeks to assess intraobserver variability. Intraclass correlation coefficients (ICCs) were calculated at a 95% confidence interval. Time required for evaluating each case was recorded. Results Both the intra- and interobserver variability showed high ICC values (more than 0.95) with low measurement variations (mean linear variations: 0.18 mm; mean angular variations: 0.25 degree). Time needed for the evaluation process ranged from 3 to 5 minutes. Conclusion This approach is time-saving, semiautomatic, and easy to learn and can be used to effectively evaluate stability after SFOA.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권2호
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• pp.152-161
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• 2007

This study was conducted to patients visited oral maxillo-facial surgery, KNUH and the purpose of the study was to assess skeletal and dento-alveolar stability after surgical-orthodontic correction treated by skeletal Class III malocclusion patients with open bite versus non-open bite. This retrospective study was based on the examination of 40 patient, 19 males and 21 females, with a mean age 22.3 years. The patients were divided into two groups based on open bite and non-open bite skeletal Class III malocclusion patients. The cephalometric records of 40 skeletal Class III malocclusion patients (open bite: n = 18, non-open bite: n = 22) were examined at different time point, i.e. before surgery(T1), immediately after surgery(T2), one year after surgery(T3). Bilateral sagittal split ramus osteotomy was performed in 40 patients. Rigid internal fixation was standard method used in all patient. Through analysis and evaluation of the cephalometric records, we were able to achieve following results of post-surgical stability and relapse. 1. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in maxillary occlusal plane angle of pre-operative stage(p>0.05). 2. Mean vertical relapses of skeletal Class III malocclusion patients with open bite were $0.02{\pm}1.43mm$ at B point and $0.42{\pm}1.56mm$ at Pogonion point. In skeletal Class III malocclusion patients with non-open bite, $0.12{\pm}1.55mm$ at B point and $0.08{\pm}1.57mm$ at Pogonion point. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in vertical relapse(p>0.05). 3. Mean horizontal relapses of skeletal Class III malocclusion patients with open bite were $1.22{\pm}2.21mm$ at B point and $0.74{\pm}2.25mm$ at Pogonion point. In skeletal Class III malocclusion patients with non-open bite, $0.92{\pm}1.81mm$ at B point and $0.83{\pm}2.11mm$ at Pogonion point. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in horizontal relapse(p>0.05). 4. There were no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in post-surgical mandibular stability(p>0.05). and we believe this is due to minimized mandibular condylar positional change using mandibular condylar positioning system and also rigid fixation using miniplate 5. Although there was no significant relapse tendency observed at chin points, according to the Pearson correlation analysis, the mandibular relapse was influenced by the amount of vertical and horizontal movement of mandibular set-back(p=0.05, r>0.304).

• Maxillofacial Plastic and Reconstructive Surgery
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• 제23권1호
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• pp.59-69
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• 2001

Purpose : The purpose of the present study was to evaluate postoperative stability and soft-tissue osseous relations of the long face syndrome patients. Methods : Twenty-five patients who had undergone bimaxillary surgery to correct long face syndrome at the Pusan National University Hospital were evaluated. The lateral cephalograms of preoperative, 1 week postoperative and at least 1 year postoperative were examined. Results : 1. The facial height of the long face syndrome patients were longer than normal Korean adults. 2. The most common malocclusion type of the long face syndrome patients in Korea was class III. 3. Horizontal postoperative skeletal relapses were $-0.64{\sim}0.80mm$ in the maxilla, and $-0.56{\sim}0.48mm$ in the mandible. 4. Vertical postoperative skeletal relapses were $0.20{\sim}0.56mm$ in the maxilla, and $-0.80{\sim}0.20mm$ in the mandible. 5. Postoperative soft tissue changes in long face syndrome patients were correlated with postoperative skeletal changes. So prediction schemes for postoperative soft-tissue changes were obtainable. Conclusion : It is hard to predict the exact direction and quantity of the postoperative skeletal relapse in long face syndrome patient's orthognathic surgery because of large standard deviation. But soft tissue change is predictable via prediction scheme.

• Journal of Oral Medicine and Pain
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• 제48권3호
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• pp.123-130
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• 2023

This case report describes the orthodontic treatment of a patient with severe anterior open bite and skeletal class II malocclusion with temporomandibular joint (TMJ) osteoarthritis (OA) of the left condyle. The 21-year-old male patient had open-bite malocclusion, mild crowding, and protrusion of the anterior teeth. Mild erosive changes were detected in the anterior part of the left mandibular condyle on cone-beam computed tomography; however, because no clinical symptoms were present, orthodontic treatment was performed. It is imperative to consider the potential implications of orthodontic treatment on the stability of the TMJ throughout the duration of treatment, as any instability can exacerbate TMJ OA. Hence, it is crucial to opt for the least invasive treatment modality available. In this regard, orthodontic treatment using a skeletal anchorage system as an alternative to conventional orthognathic surgery for patients with open bite holds great promise, as it not only ensures mandibular stability but also significantly ameliorates the open-bite condition.

• 구강회복응용과학지
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• 제22권4호
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• pp.271-281
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• 2006

Long term prediction of surgical result of skeletal class III has not been evaluated adequately because the stability of orthognathic surgery would be affected by not only set back amount of mandible but also many other factors like skeletal pattern, hyoid position, and airway size. The aimof this study is to discriminate the factors which affect the stability of post-treatment result of surgical outcome of sagittal split ramus osteotomy. We have collected 37 patients (male: 17, female: 20) from patients who have been treated at Orthodontic Department in Dankook University. The patients underwent 3 times Cephalometric X-ray taking at pre-, post-orthognathic surgery and after 12 months retention. The subjects were divided into 2 groups (Stable group: 21, Relapse group: 16) according to their relapse amount. We have taken following results from Students t-test and discriminant analysis. The discriminant factors which discern relapse and stable groupe among treatment change variables were BX and Ba-HY. Hyoid bone moved to posterior and inferior position due to surgery and repositioned superiorly and posteriorly during retention period. Skeletal patterns of the relapse group are smaller mandibular plane angle, anterior mandibular position, and greater distance from hyoid bone to cervical bone and mandible respectively.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제37권
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• pp.6.1-6.9
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• 2015

Orthognathic surgery requires stable fixation for uneventful healing of osteotomized bony segments and optimal remodeling. Titanium plates and screws have been accepted as the gold standard for rigid fixation in orthognathic surgery. Although titanium osteofixation is the most widely used approach, the use of bioabsorbable devices has been increasing recently. Biodegradation of bioabsorbable devices eliminates the need for a second operation to remove metal plates and screws. However, long-term stability and relapse frequency in bioabsorbable osteofixation are still insufficiently studied, especially in cases of segmental movements of great magnitude or segmental movements to a position where bony resistance exists. This paper reviews the background, techniques, and complications of bioabsorbable osteofixation and compares bioabsorbable and titanium osteofixation in orthognathic surgery in terms of skeletal stability.

• 대한치과교정학회지
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• 제54권2호
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• pp.89-107
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• 2024

Objective: This systematic review aimed to provide a comparative analysis of the treatment outcomes, including hard and soft tissues, postoperative stability, temporomandibular disorders (TMD), and quality of life (QoL), in patients with facial asymmetry who underwent orthognathic surgery. Methods: The primary objective was to address the question, "How do different factors related to surgery affect the outcomes and stability of orthognathic surgery in the correction of facial asymmetry?" A meta-analysis was conducted on the outcome parameters, such as skeletal, dental, and soft tissue symmetry, TMD, QoL, and relapse, using the Hartung-Knapp-Sidik-Jonkman method for random-effects models. Subgroup analyses were conducted considering surgery-related factors such as surgical techniques (one-jaw vs. two-jaw), use of the surgery-first approach, utilization of computer simulation, and analytical methods employed to evaluate asymmetry (2D vs. 3D). Results: Forty-nine articles met the inclusion criteria. The metaanalysis demonstrated a significant improvement in the symmetry of hard and soft tissues. The subgroup analysis indicated that the treatment outcomes showed significant improvement, regardless of the factors related to surgery. Changes in TMD signs and symptoms varied according to the surgical technique used. Quality of life improved in the facial, oral, and social domains. Skeletal relapse was observed during the follow-up. Conclusions: Our findings support the positive outcomes of orthognathic surgery in the treatment of facial asymmetry in terms of skeletal and soft tissue improvements, stability, relief of TMD symptoms, and enhancement of QoL. However, most of the included studies showed a low certainty of evidence and high heterogeneity.

• 대한두개안면성형외과학회지
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• 제13권1호
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• pp.4-10
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• 2012

Purpose: The objective of this retrospective study was to assess the skeletal stability after orthognathic surgery for patients with cleft lip and palate. The soft tissue changes in relation to the skeletal movement were also evaluated. Methods: Thirty one patients with cleft received orthognathic surgery by one surgeon at the Craniofacial Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan. Osseous and soft tissue landmarks were localized on lateral cephalograms taken at preoperative (T0), postoperative (T1), and after completion of orthodontic treatment (T2) stages. Surgical movement (T0.T1) and relapse (T1.T2) were measured and compared. Results: Mean anteroposterior horizontal advancement of maxilla at point A was 5.5 mm, and the mean horizontal relapse was 0.5 mm (9.1%). The degree of horizontal relapse was found to be correlated to the extent of maxillary advancement. Mean vertical lengthening of maxilla at point A was 3.2 mm, and the mean vertical relapse was 0.6 mm (18.8%). All cases had maxillary clockwise rotation with a mean of 4.4 degrees. The ratio for horizontal advancement of nasal tip/anterior nasal spine was 0.54/1, and the ratio of A' point/A point was 0.68/1 and 0.69/1 for the upper vermilion/upper incisor tip. Conclusion: Satisfactory skeletal stability with an acceptable relapse rate was obtained from this study. High soft tissue to skeletal tissue ratios were obtained. Two-jaw surgery, clockwise rotation, rigid fixation, and alar cinch suture appeared to be the contributing factors for favorable results.

• Structural Engineering and Mechanics
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• 제57권6호
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• pp.1065-1084
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• 2016

The analysis and design of skeletal structures is greatly influenced by the behaviour of beam-to-column connections, where patented designs have led to a wide range of types with differing structural quantities. The behaviour of beam-to-column connections plays an important role in the analysis and design of framed structures. This paper presents an overview of the influence of connection behaviour on structural stability, in the in-plane (bending) mode of sway. A computer-based method is presented for geometrically nonlinear plane frames with semi-rigid connections accounting for shear deformations. The analytical procedure employs transcendental modified stability functions to model the effect of axial force on the stiffness of members. The member stiffness matrix were found. The critical load has been searched as a suitable load parameter for the loss of stability of the system. Several examples are presented to demonstrate the validity of the analysis procedure. The method is readily implemented on a computer using matrix structural analysis techniques and is applicable for the efficient nonlinear analysis of frameworks. Combined with a parametric column effective length study, connection and frame stiffness are used to propose a method for the analysis of semi-rigid frames where column effective lengths are greatly reduced and second order (deflection induced) bending moments in the column may be distributed via the connectors to the beams, leading to significant economies.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제36권4호
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• pp.255-261
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• 2010

Introduction: To evaluate the skeletal stability after a bilateral sagittal split osteotomy (BSSO) setback of the mandible fixed with a biodegradable internal fixation device or metal internal fixation device. Materials and Methods: Thirty consecutive patients underwent mandibular setback via BSSO. Fifteen patients were fixed with a biodegradable internal fixation device or metal internal fixation device respectively. Posteroanterior (PA) and lateral cephalograms were taken preoperatively and at two days, 5.5 months and 14.5 months postoperatively. The relevant skeletal points were traced and digitized to evaluate the skeletal changes postoperatively. The relapse rates were analyzed and compared statistically. Results: There was no statistically significant differences in postoperative stability between the two groups.(P<0.05) Conclusion: The biodegradable internal fixation device may make an effective device alternative to a metal internal fixation device for setback BSSO.