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Yi Zhang - One of the best experts on this subject based on the ideXlab platform.
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one stage technique for sagittal split ramus osteotomy combined with mandibular angle ostectomy
Scientific Reports, 2018Co-Authors: Shuo Chen, Yi ZhangAbstract:Bilateral sagittal split ramus osteotomy (BSSRO) is commonly used to correct mandibular Prognathism or retrognathism. Patients with mandibular Prognathism or retrognathism may also present with a prominent mandibular angle. In this paper, we share our experience on BSSRO with mandibular angle resection. Eleven patients who were treated from July 2014 to December 2016 were included in this study. The mandibular angle was resected through the medial side of the mandible after BSSRO. The mandibular angle measurements of the patients changed significantly after surgery (p < 0.05). Unanticipated fractures and mandibular hematoma did not occur. Therefore, BSSRO combined with mandibular angle ostectomy through the medial side of the mandible can be used to safely and effectively correct facial deformity.
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One-stage technique for sagittal split ramus osteotomy combined with mandibular angle ostectomy
Nature Publishing Group, 2018Co-Authors: Shuo Chen, Yi ZhangAbstract:Abstract Bilateral sagittal split ramus osteotomy (BSSRO) is commonly used to correct mandibular Prognathism or retrognathism. Patients with mandibular Prognathism or retrognathism may also present with a prominent mandibular angle. In this paper, we share our experience on BSSRO with mandibular angle resection. Eleven patients who were treated from July 2014 to December 2016 were included in this study. The mandibular angle was resected through the medial side of the mandible after BSSRO. The mandibular angle measurements of the patients changed significantly after surgery (p
Minsuk Kook - One of the best experts on this subject based on the ideXlab platform.
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condylar positioning changes following unilateral sagittal split ramus osteotomy in patients with mandibular Prognathism
Maxillofacial plastic and reconstructive surgery, 2015Co-Authors: Myungin Kim, Junhwa Kim, Seunggon Jung, Hongju Park, Sunyoul Ryu, Minsuk KookAbstract:Background This study was performed to evaluate three-dimensional positional change of the condyle using three-dimensional computed tomography (3D-CT) following unilateral sagittal split ramus osteotomy (USSRO) in patients with mandibular Prognathism.
Shuo Chen - One of the best experts on this subject based on the ideXlab platform.
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one stage technique for sagittal split ramus osteotomy combined with mandibular angle ostectomy
Scientific Reports, 2018Co-Authors: Shuo Chen, Yi ZhangAbstract:Bilateral sagittal split ramus osteotomy (BSSRO) is commonly used to correct mandibular Prognathism or retrognathism. Patients with mandibular Prognathism or retrognathism may also present with a prominent mandibular angle. In this paper, we share our experience on BSSRO with mandibular angle resection. Eleven patients who were treated from July 2014 to December 2016 were included in this study. The mandibular angle was resected through the medial side of the mandible after BSSRO. The mandibular angle measurements of the patients changed significantly after surgery (p < 0.05). Unanticipated fractures and mandibular hematoma did not occur. Therefore, BSSRO combined with mandibular angle ostectomy through the medial side of the mandible can be used to safely and effectively correct facial deformity.
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One-stage technique for sagittal split ramus osteotomy combined with mandibular angle ostectomy
Nature Publishing Group, 2018Co-Authors: Shuo Chen, Yi ZhangAbstract:Abstract Bilateral sagittal split ramus osteotomy (BSSRO) is commonly used to correct mandibular Prognathism or retrognathism. Patients with mandibular Prognathism or retrognathism may also present with a prominent mandibular angle. In this paper, we share our experience on BSSRO with mandibular angle resection. Eleven patients who were treated from July 2014 to December 2016 were included in this study. The mandibular angle was resected through the medial side of the mandible after BSSRO. The mandibular angle measurements of the patients changed significantly after surgery (p
Tae-geon Kwon - One of the best experts on this subject based on the ideXlab platform.
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three dimensional analysis of mandibular condyle position in patients with deviated mandibular Prognathism
International Journal of Oral and Maxillofacial Surgery, 2017Co-Authors: J S Lee, Tae-geon KwonAbstract:The purpose of this study was to evaluate the bilateral difference in condyle position in patients with deviated mandibular Prognathism. Patients with asymmetrical (n=28) and symmetrical mandibular Prognathism (n=23) were compared using the three-dimensional (3D) reformatted image from cone beam computed tomography. Significant positional differences in the condyle and subcondyle region (sigmoid notch) were found between the deviated and contralateral sides in the group with asymmetrical mandibular Prognathism, but not in the control group. The lateral condyle was more laterally and inferiorly positioned on the contralateral side than on the deviated side (P<0.05). The sigmoid notch was more laterally, superiorly, and posteriorly positioned on the deviated side (P<0.01). Interestingly, condyle width and height on the deviated side was narrower and shorter than on the contralateral side and in the control group. Menton deviation was closely correlated with the bilateral difference in condyle height and 3D position of the sigmoid notch (P<0.01). The degree of asymmetry was more highly correlated with condyle height than with the spatial orientation of the condyle head. The results demonstrated that mandibular Prognathism with asymmetry is associated with bilateral differences in 3D morphology and orientation of the condyle. Therefore, clinicians should consider these variations during surgical planning.
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obwegeser ii osteotomy transoral angle osteotomy for open bite with skeletal class iii deformity
Journal of Cranio-maxillofacial Surgery, 2014Co-Authors: Tae-geon Kwon, Sanghan LeeAbstract:Abstract Introduction This study evaluated postoperative stability after Obwegeser II osteotomy (transoral angle osteotomy, first reported by Obwegeser 1973) for severe open bite with mandibular Prognathism. Patients and methods This retrospective study reviewed 20 consecutive patients who underwent only mandibular Obwegeser II osteotomy to correct open bite and mandibular Prognathism. Lateral cephalograms were evaluated preoperatively (T1), immediate postoperatively (T2) and at least 6 months after the surgery (T3). Surgical and postsurgical changes in cephalometric measurements were evaluated statistically. Results Open bite with skeletal class III malocclusion was corrected by the Obwegeser II osteotomy alone. After an average of 9.9 ± 5.2 mm of mandibular setback with open bite closure (T2–T1, over-bite change, 5.7 ± 2.4 mm) by counter-clockwise rotation of the mandible, the patients showed 0.8 ± 1.7 mm of horizontal relapse ( p > 0.05), 1.1 ± 1.7 mm of vertical relapse at the B point ( p = 0.011) and −0.2 ± 1.6 mm of over-bite change postoperatively (T3–T2). Discussion With the adequate control of the condylar position with rigid internal fixation, Obwegeser II osteotomy showed acceptable stability after the correction of open bite with mandibular Prognathism without a simultaneous maxillary osteotomy. An isolated Obwegeser II osteotomy can be considered a reliable option in cases with moderate to severe open bite with mandibular Prognathism when the maxillary osteotomy is not needed if the patients have a well-positioned maxilla.
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does skeletal surgery for asymmetric mandibular Prognathism influence the soft tissue contour and thickness
Journal of Oral and Maxillofacial Surgery, 2013Co-Authors: Sung Tak Lee, Yoshihide Mori, Katsuhiro Minami, Jinwoo Park, Tae-geon KwonAbstract:Materials and Methods: The present retrospective study included skeletal class III patients with significant mandibular chin deviation greater than 6 mm at the pogonion, who had undergone cone-beam computed tomography before and 6 months after surgery during a 2-year period. The predictor variables were timing (pre- and postoperatively) and side (asymmetric vs contralateral). The outcome measures were the hard and soft tissue contours and soft tissue thickness of the chin at the infradentale, B-point, and pogonion level evaluated with reformatted computed tomographyimages. The study variables were statistically compared using regression model and correlation analysis. Results: The present study consisted of 20 patients (10 males and 10 females; average age 20.2 years; range, 18 to 25). Preoperatively, the chin deviation side showed a more prominent hard and soft tissue outline but had a thinner soft tissue thickness, which camouflaged the hard tissue asymmetry. After surgery, the hard and soft tissue outline was greatly improved, and the soft tissue thickness had become nearly symmetric. Most of the soft tissue thickness changes correlated negatively with the hard tissue changes. Conclusions: Asymmetric mandibular Prognathism accompanied the 3-dimensional soft tissue contour and thickness asymmetry. Because the soft tissue responds favorably after skeletal surgery, the correction of 3-dimensional asymmetry of bone should be emphasized in patients with asymmetric mandibular Prognathism.
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Polymorphisms in the Matrilin-1 Gene and Risk of Mandibular Prognathism in Koreans
Journal of dental research, 2010Co-Authors: J.y. Jang, E.k. Park, Hyun-mo Ryoo, Hong-in Shin, T.h. Kim, Jin Sung Jang, H.s. Park, J.y. Choi, Tae-geon KwonAbstract:Previous linkage analysis of an Asian population proposed possible candidate genes for mandibular Prognathism, such as Matrilin-1 (cartilage matrix protein). To investigate the association between the single-nucleotide polymorphisms (SNPs) in Matrilin-1 and mandibular Prognathism, we investigated three sequence variants (-158 T>C, 7987 G>A, 8572 C>T) in 164 mandibular Prognathism patients and 132 control individuals with a normal occlusion. The results showed that the 8572 TT genotypes in Matrilin-1 showed increased risk of mandibular Prognathism (OR = 9.28, 95% Cl = 1.19~197.57, P < 0.05), whereas the 7987 AA genotype showed a protective effect for mandibular Prognathism (OR = 0.16, 95% Cl = 0.05~0.47, P < 0.05). Genotyping results showed that the Matrilin-1 polymorphism haplotype TGC (ht4; 158T, 7987G, and 8572C alleles) had a pronounced risk effect for mandibular Prognathism compared with controls (OR = 5.16, 95% Cl = 2.03~13.93, P < 0.01). The results suggest that polymorphisms in Matrilin-1 could be ...
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relationship between the masticatory muscles and mandibular skeleton in mandibular Prognathism with and without asymmetry
Journal of Oral and Maxillofacial Surgery, 2007Co-Authors: Tae-geon Kwon, Hyun-mo Ryoo, Kiho Lee, Hyosang Park, Hyunjung Kim, Sanghan LeeAbstract:Purpose The purpose of the present study was to evaluate the relationship between masticatory muscle volume and mandibular skeletal measurements in patients with and without facial asymmetry. This was done in order to determine whether asymmetric mandibular Prognathism is related to masticatory muscle asymmetry. Patients and Methods The study was conducted with 40 adult patients with mandibular Prognathism composed of 2 groups, the asymmetry group (n = 20) and the nonasymmetry group (n = 20). Using 3-dimensional reformatted computed tomography (CT) images, the volume of masticatory muscle (masseter, temporal, medial, and lateral pterygoid muscles) and various skeletal measurements (hemimandibular volume, ramal height, body length, mandibular length, gonial angle) were evaluated and compared. The right-left difference was expressed by an asymmetry index {(right − left)/left, %}. Results The results showed that in the asymmetry group, the longer mandibular side (contralateral side of chin deviation) exhibited longer ramal and body length, a wider gonial angle, and more hemimandibular volume with less medial pterygoid volume, whereas the nonasymmetry group did not show a statistical bilateral difference between the skeletal and muscular measurements. The correlation analysis showed that patients with facial asymmetry did not have similar patterns of muscle-bone relation as compared with the symmetrical subjects. Conclusion In patients with mandibular Prognathism, the bilateral difference in muscle volume would reflect the difference in the spatial anatomy of a skeletal structure and could not predict mandibular skeletal asymmetry.
Junyoung Paeng - One of the best experts on this subject based on the ideXlab platform.
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glossectomy in the severe maxillofacial vascular malformation with jaw deformity a rare case report
Maxillofacial plastic and reconstructive surgery, 2015Co-Authors: Minhyeog Park, Dongyoung Chung, Junyoung PaengAbstract:In the field of oral-maxillofacial surgery, vascular malformations present in various forms. Abnormalities in the size of the tongue by vascular malformations can cause mandibular Prognathism and skeletal deformity. The risk in surgical treatment for patients with vascular malformation is high, due to bleeding from vascular lesions. We report a rare case of macroglossia that was treated by partial glossectomy, resulting in an improvement in the swallowing and mastication functions in the patient. A 25-year-old male patient with severe open-bite and mandibular Prognathism presented to our department for the management of macroglossia. The patient had a difficulty in food intake because of the large tongue. Orthognathic surgery was not indicated because the patient had severe jaw bone destruction and alveolar bone resorption. Therefore, the patient underwent partial glossectomy under general anesthesia. There was severe hemorrhaging during the surgery, but the bleeding was controlled by local procedures.
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comparative study of skeletal stability between bicortical resorbable and titanium screw fixation after sagittal split ramus osteotomy for mandibular Prognathism
Journal of Cranio-maxillofacial Surgery, 2012Co-Authors: Junyoung Paeng, Jongrak Hong, Changsoo Kim, Myungjin KimAbstract:Abstract Introduction Resorbable screw fixation for orthognathic surgery is widely used in oral and maxillofacial surgery and has several advantages. However, surgeons are concerned about using resorbable screws in orthognathic surgery because of possible postoperative complications such as relapse, screw fracture, and infection. The purpose of this study was to evaluate the skeletal stability of bicortical resorbable screw fixation after sagittal split ramus osteotomies for mandibular Prognathism. Materials and methods This study included 25 patients who underwent mandibular setback surgery fixed with resorbable screws after sagittal split osteotomy at the Department of Oral and Maxillofacial Surgery at Seoul National University Dental Hospital. Five resorbable screws (Inion CPS®, Inion Ltd., Finland) were applied bicortically at each osteotomy site via a transbuccal approach. No rigid intermaxillary fixation was applied on the first postoperative day. Passive mouth opening exercises were allowed, using two light, rubber elastics for guidance. The control group was 25 patients fixed with four titanium screws. The follow-up period was 12–22 months (mean 17.8 months). Postoperative skeletal changes on lateral cephalometric radiographs were analyzed and compared between the two groups preoperatively, immediately postoperatively, and 6 months postoperatively. Results The average setback was 6.9 mm and no major intraoperative complications occurred. One patient experienced infection immediately after surgery that was controlled uneventfully. The data did not demonstrate any significant difference in postoperative skeletal stability between the two groups. Differences between the immediate postoperative state and 6 months after surgery were not significant. In earlier cases, especially for patients with severe mandibular Prognathism, immediate postoperative elastic traction was needed for stable occlusal guidance. Conclusions The results of this study indicate that bicortical resorbable screws offer a clinically stable outcome for the fixation of mandibular sagittal split osteotomies in mandibular Prognathism. However the resorbable screws showed less stable results vertically than the titanium screws.