• Maxillofacial Plastic and Reconstructive Surgery
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• 제33권2호
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• pp.137-143
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• 2011

Purpose: Orthognathic surgery is required in patients with severe skeletal disharmony and facial asymmetry, which results in functional and esthetic improvement. Recently, bimaxillary surgery has become generalized. Establishment of the occlusal plane among several other factors included in the surgery plan is a major consideration for the diagnosis and treatment plan and it is also an important factor for postoperative stability. Methods: In this study, we assessed postoperative stability of occlusal plane, B-point, and pogonion point on 20 patients who underwent two-jaw surgery in the Chosun Dental Hospital from 2000 to 2007. Preoperative and postoperative states and at least a one year postoperative follow-up were compared. Results: The postsurgical relapse volume of the occlusal plane to the SN plane and the FH plane was $-0.26{\pm}2.8^{\circ}$ and $-0.44{\pm}3.29^{\circ}$, respectively and after two-jaw surgery, the stability of occlusal plane was maintained. The horizontal relapse degree was $0.85{\pm}0.46$ mm and $0.76{\pm}0.48$ mm, respectively, and the vertical relapse degree was $1.16{\pm}0.36$ mm and $1.13{\pm}0.71$ mm of the B point and the Pogonion point at the time after minimal 1 year. Conclusion: The vertical relapse amount was shown to be slightly larger than the horizontal relapse amount.

• 대한치과교정학회지
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• 제45권1호
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• pp.3-12
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• 2015

Objective: We compared the skeletal and dental changes that resulted from the use of two methods of intermaxillary fixation (IMF)-miniscrews and surgical archwire-in 74 adult patients who had Class III malocclusion and were treated with the same orthognathic surgical procedure at a hospital in Korea. Methods: All the patients underwent Le Fort I osteotomy and bilateral sagittal split ramus osteotomy with rigid fixation. They were divided into two groups according to the type of IMF used-group 1 underwent surgical archwire fixation and group 2 underwent orthodontic miniscrew fixation. In a series of cephalograms for each patient, we compared vertical and horizontal tooth-position measurements: (a) immediately after surgery ($T_0$), (b) 3 months after surgery ($T_1$), and (c) 6 months after surgery ($T_2$). Cephalometric changes within each group were examined using one-way analysis of variance (ANOVA) while the independent samples t -test procedure was used to compare the two groups. Results: After surgery, the maxillary incisors tended to be proclined in both groups although there were no significant differences. Incisor overbite increased significantly in both groups from $T_0$ to $T_1$, and the miniscrew group (group 2) showed slightly greater overbite than the archwire group (group 1). Conclusions: This study suggest that the use of orthodontic miniscrews and orthodontic surgical archwire for IMF in adult patients results in similar skeletal and dental changes.

• 대한치과교정학회지
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• 제43권1호
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• pp.42-52
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• 2013

The aim of this paper was to propose a new method of bimaxillary orthognathic surgery planning and model surgery based on the concept of 6 degrees of freedom (DOF). A 22-year-old man with Class III malocclusion was referred to our clinic with complaints of facial deformity and chewing difficulty. To correct a prognathic mandible, facial asymmetry, flat occlusal plane angle, labioversion of the maxillary central incisors, and concavity of the facial profile, bimaxillary orthognathic surgery was planned. After preoperative orthodontic treatment, surgical planning based on the concept of 6 DOF was performed on a surgical treatment objective drawing, and a Jeon's model surgery chart (JMSC) was prepared. Model surgery was performed with Jeon's orthognathic surgery simulator (JOSS) using the JMSC, and an interim wafer was fabricated. Le Fort I osteotomy, bilateral sagittal split ramus osteotomy, and malar augmentation were performed. The patient received lateral cephalometric and posteroanterior cephalometric analysis in postretention for 1 year. The follow-up results were determined to be satisfactory, and skeletal relapse did not occur after 1.5 years of surgery. When maxillary and mandibular models are considered as rigid bodies, and their state of motion is described in a quantitative manner based on 6 DOF, sharing of exact information on locational movement in 3-dimensional space is possible. The use of JMSC and JOSS will actualize accurate communication and performance of model surgery among clinicians based on objective measurements.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권6호
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• pp.457-463
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• 2011

Introduction: This study evaluate the soft tissue changes to the upper lip and nose after Le Fort I maxillary posterosuperior rotational movement. Materials and Methods: Twenty Skeletal class III patients, who had undergone bimaxillary surgery with a maxillary Le Fort I osteotomy and bilateral sagittal split ramus osteotomy, were included in the study. The surgical plan for maxilla was posterosuperior rotational movement, with the rotation center in the anterior nasal spine (ANS) of maxilla. Soft and hard tissue changes were measured by evaluating the lateral cephalograms obtained prior to surgery and at least 6 months after surgery. For cephalometric analysis, four hard tissue landmarks ANS, posterior nasal spine [PNS], A point, U1 tip), and five soft tissue landmarks (pronasale [Pn], subnasale [Sn], A' Point, upper lip [UL], stomion superius [StmS]) were marked. A paired t test, Pearson's correlation analysis and linear regression analysis were used to evaluate the soft and hard tissue changes and assess the correlation. A P value <0.05 was considered significant. Results: The U1 tip moved $2.52{\pm}1.54$ mm posteriorly in the horizontal plane (P<0.05). Among the soft tissue landmarks, Pn moved $0.97{\pm}1.1$ mm downward (P<0.05), UL moved $1.98{\pm}1.58$ mm posteriorly (P<0.05) and $1.18{\pm}1.85$ mm inferiorly (P<0.05), and StmS moved $1.68{\pm}1.48$ mm posteriorly (P<0.05) and $1.06{\pm}1.29$ mm inferiorly (P<0.05). The ratios of horizontal soft tissue movement to the hard tissue were 1:0.47 for the A point and A' point, and 1:0.74 for the U1 tip and UL. Vertically, the movement ratio between the A point and A' point was 1:0.38, between U1 tip and UL was 1:0.83, and between U1 tip and StmS was 1:0.79. Conclusion: Posterosuperior rotational movement of the maxilla in Le Fort I osteotomy results in posterior and inferior movement of UL. In addition, nasolabial angle was increased. Nasal tip and base of the nose showed a tendency to move downward and showed significant horizontal movement. The soft tissue changes in the upper lip and nasal area are believed to be induced by posterior movement at the UL area.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제14권3호
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• pp.217-227
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• 1992

The purpose of this paper is to investigate changes in soft tissue in 22 patients treated by vertical ramus osteotomy and sagittal split ramus osteotomy for the correction of mandibular prognathism. 22 individuals, 12 males and 10 females, were selected from the patients with mandibular prognathism at the Department of Oral and Maxillofacial Surgery, Colledge of Dentistry, Kyung Hee University. Patient were analyzed with cephalogram taken 1 week before and at least 6 weeks after surgery under the same condition. Measurements were made constructed hard tissue and sop tissue points located on each before-and-after film tracing. Comparision were made of these figures to estimate the amount that the soft tissue followed the hard tissue structures in each surgical procedure : ratio of sop and hard tissue changes were formulated. The results were as follows. 1. The horizontal changes of Pogs and Bs as a ratio of the horizontal changes of Pog and B point were 1.02 and 1.16 respectively. 2. One millimeter of posterior changes at Pog resulted in 0.86mm of posterior change at Li and 0.09mm of posterior change at Ls. The greatest amount of sop tissue change occurred at Pogs, with substantially less posterior displacement at Bs, even less at Li and at least at Ls. 3. The ratio of LI to Li was 1:0.81 and the ratio of LI to Ls was not significant.(1 : 0.17) 4. The ULA(Cm-Sn-Ls) and the relative lower lip projection (LLP) was incnease4 but the relative upper lip projection (ULP) was slightly decreased 5. The angular change of the upper lip inclined angle (Ls-Sn/ANS-PNS) and lower lip inclined angle(Li-Pogs/Me-Go) expressed as a ratio of the posterior change of Pog were 0.57 and 0.20 respectively. 6. The ratio of the lower anterior facial height change of the soft tissue(Sn-Mes) to the hard tissue(ANS-Gn) were 0.78 and and the ratio of vertical height changes of the hard tissue and sop tissue to the posterior change of the Pog were 0.18 and 0.19 respectively. 7. The sop tissue angular change of facial convexity(G-Sn-Pogs) expressed as a ratio of the angular change of the hard tissue angle of facial convexity(N-A-Pog) was 1.24.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권6호
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• pp.404-412
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• 2012

Purpose: The purpose of this study was to evaluate postsurgical facial hard tissue stability after orthognathic surgery with/without posterior impaction in skeletal class III malocclusion patients, and to evaluate the horizontal relapse tendency, according to changes in anteroposterior discrepancy and occlusal planes. Methods: Ninety patients, who had undergone orthognathic surgery in Pusan National University Dental Hospital, were enrolled in this study. Three main groups were classified as follows: Thirty patients underwent mandibular setback bilateral sagittal split ramus osteotomy (BSSRO) only (BSSRO group, BG); another thirty patients underwent mandibular setback BSSRO and Le Fort I osteotomy with posterior impaction (posterior impaction group, PG); and another thirty patients underwent mandibular setback BSSRO and Le Fort I osteotomy without posterior impaction (non-posterior impaction group, NPG). Preoperative (T0), immediate postoperative (T1) and six-month follow-up period (T2) lateral cephalograms were taken, and various parameters were measured. The analyses were done by linear and angular measurements between T0-T1 and T1-T2, to evaluate postsurgical facial hard tissue stability. Results: Mean horizontal relapse rates were distributed from 11.81% to 19.08%, and there were significant postsurgical changes (0.52 mm~2.44 mm) at the B point in all 3 groups. But, there were no statistical differences on relapse rate among BG, PG and NPG patients. Conclusion: In this study, the postsurgical stabilities of BSSRO and Le Fort I osteotomy with/without posterior impaction in skeletal class III malocclusion patients were acceptable. There were no significant statistical differences in mandibular stability according to changes in anteroposterior discrepancy and occlusal planes.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권4호
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• pp.264-271
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• 2011

Purpose: This study evaluated retrospectively the postsurgical facial hard tissue profile of a Le Fort I osteotomy with/without posterior impaction and rigid internal fixation to correct mandibular prognathism. After observing a difference between the two groups, this measurement was used to prepare a treatment plan for 2-jaw surgery. Patients and Methods: Thirty patients who had undergone orthognathic surgery in Pusan National University Dental Hospital were enrolled in this study. Fifteen patients were treated using a Le Fort I osteotomy with posterior impaction and mandibular setback bilateral sagittal split ramus osteotomy, and the other fifteen patients were treated without posterior impaction. The preoperative (T0), immediate postoperative (T1) and six-month follow-up period (T2) cephalograms were taken and difference between T1-T0 and T2-T2 was analyzed. Results: Both groups was FH-ABp, SNB and ANB showed significant changes in the measurement, whereas only the posterior impaction group showed a change in the SN-U1, occlusal plane, posterior facial height, surgical movement difference from the L1 and B-point. There was no significant statistical change between the immediate postoperative (T1) and six-month follow-up (T2) hard tissue analysis in the two groups. Conclusion: A Le Fort I osteotomy with posterior impaction is considerable for patients with a flat occlusal plane angle, large posterior facial height, prominent B-point, pogonion and labioversed incisal inclination if the indications are well chosen.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제40권
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• pp.4.1-4.4
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• 2018

Background: Along with the advances in technology of three-dimensional (3D) printer, it became a possible to make more precise patient-specific 3D model in the various fields including oral and maxillofacial surgery. When creating 3D models of the mandible and maxilla, it is easier to make a single unit with a fused temporomandibular joint, though this results in poor operability of the model. However, while models created with a separate mandible and maxilla have operability, it can be difficult to fully restore the position of the condylar after simulation. The purpose of this study is to introduce and asses the novel condylar repositioning method in 3D model preoperational simulation. Methods: Our novel condylar repositioning method is simple to apply two irregularities in 3D models. Three oral surgeons measured and evaluated one linear distance and two angles in 3D models. Results: This study included two patients who underwent sagittal split ramus osteotomy (SSRO) and two benign tumor patients who underwent segmental mandibulectomy and immediate reconstruction. For each SSRO case, the mandibular condyles were designed to be convex and the glenoid cavities were designed to be concave. For the benign tumor cases, the margins on the resection side, including the joint portions, were designed to be convex, and the resection margin was designed to be concave. The distance from the mandibular ramus to the tip of the maxillary canine, the angle created by joining the inferior edge of the orbit to the tip of the maxillary canine and the ramus, the angle created by the lines from the base of the mentum to the endpoint of the condyle, and the angle between the most lateral point of the condyle and the most medial point of the condyle were measured before and after simulations. Near-complete matches were observed for all items measured before and after model simulations of surgery in all jaw deformity and reconstruction cases. Conclusions: We demonstrated that 3D models manufactured using our method can be applied to simulations and fully restore the position of the condyle without the need for special devices.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제29권4호
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• pp.340-352
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• 2007

In this systematic review on bone reduction procedures for the correction of the prominent mandibular angle, we collected and sorted the methods. The strength and weakness, indication, complication, and final esthetic result of each method were evaluated. After searching and filtering the literatures on the base of inclusion criteria, 9 eligible case series studies were included in this study. There were 3 types of curved ostectomies and 4 types of lateral cortical ostectomies. Surgical procedures for curved ostectomies were divided into 2 types. One was single curved ostectomy and the other was multistaged curved ostectomy. Lateral cortical ostectomies reported were all similar to sagittal split ramus osteotomy. The complications reported in the included studies were scarce, but curved ostectomies may be able to induce many complications. The prominent mandibular angle must be analyzed in the lateral dimension and frontal dimension, and curved ostectomy can reduce the mandibular angle laterally while lateral cortical ostectomy can reduce the bigonial distance frontally. Because curved ostectomies can induce complications and unnaturally large mandibular angle while can not reduce bigonial distance efficiently, the current trend for the angle reduction procedure is lateral cortical ostectomies.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제31권4호
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• pp.294-305
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• 2009

Purpose: This retrospective study evaluated the changes in hyoid bone and tongue positions as well as oral cavity volume after mandibular setback by BSSRO. Materials and Methods: 18 Koreans who underwent BSSRO to correct mandibular prognathism were studied. Lateral cephalograms were taken and traced preoperatively (T0), immediately (T1) and approximately 6 months postoperatively (T2). Submentovertex radiograghs were taken and traced before surgery (T0) and about 6 months after surgery (T2). The area and volume of oral cavity, the vertical and horizontal dimensions of the hyoid bone and tongue dorsum were measured. Results: Mandibular setback surgery resulted in a significant reduction of lower oral cavity volume. The hyoid bone displaced posteroinferiorly immediately after surgery, and it tended to return to its original vertical position at 6 month after mandibular setback by BSSRO. The retropalatal space around tongue was maintained and the retrolingual space around tongue was reduced immediately postoperatively. The readaptation of tongue was not evident for that the follow up period was not long enough. No significant statistical correlations between the amounts of mandibular setback and the changes of oral cavity volume were observed. Conclusion: Mandibular setback surgery resulted in a significant reduction of lower oral cavity volume, which was most likely attributable to the posterior movement of the mandible. More subjects and long-term observations should be performed to assess the changes of oropharyngeal configuration following mandibular setback surgery.