• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.4
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• pp.276-281
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• 2017

This case series study demonstrates the possibility of successful implant rehabilitation without bone augmentation in the atrophic posterior maxilla with cystic lesion in the sinus. Sinus lift without bone graft using the lateral approach was performed. In one patient, the cyst was aspirated and simultaneous implantation under local anesthesia was performed, whereas the other cyst was removed under general anesthesia, and the sinus membrane was elevated in a second process, followed by implantation. In both cases, tapered 11.5-mm-long implants were utilized. With all of the implants, good stability and appropriate bone height were achieved. The mean bone level gain was 5.73 mm; adequate bone augmentation around the implants was shown, the sinus floor was moved apically, and the cyst was no longer radiologically detected. Completion of all of the treatments required an average of 12.5 months. The present study showed that sufficient bone formation and stable implantation in a maxilla of insufficient bone volume are possible through sinus lift without bone materials. The results serve to demonstrate, moreover, that surgical treatment of mucous retention cyst can facilitate rehabilitation. These techniques can reduce the risk of complications related to bone grafts, save money, and successfully treat antral cyst.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.4
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• pp.239-246
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• 2017

Objectives: This paper proposes Han's ratio as an objective and quantitative comparative result obtained from pre and postoperative data in patients with a mandibular angle reduction. Materials and Methods: Thirty patients, 12 men and 18 women, who visited the Department of Oral and Maxillofacial Surgery with the chief complaints of skeletal mandibular prognathism and prominent mandibular angle were selected. The subjects were classified into 3 groups according to the types of surgical procedures involved. Group A consisted of patients who underwent mandibular angle resection and mandibular setback. Group B was comprised of patients with mandibular angle resection, mandibular setback and genioplasty. Group C consisted of patients with mandibular angle resection, mandibular setback, Le Fort I osteotomy, and genioplasty. The landmarks placed in pre and postoperative frontal photographs were used to obtain the Han's ratio in each group. The Han's ratios were compared pre- and postoperation and according to the surgical techniques applied. Results: Of the 3 groups who had undergone a mandibular angle resection, all showed a statistically significant increase in Han's ratio. On the other hand, there was no statistically significant difference based on the surgical techniques used. Conclusion: The ratio of the lateral lower face proposed in this study is a potential indicator of postoperative esthetic enhancement in mandibular angle reduction surgery.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.4
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• pp.256-261
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• 2017

Objectives: The concept of natural head position (NHP) was first introduced by Broca in 1862, and was described as a person's stable physiologic position "when a man is standing and his visual axis is horizontal." NHP has been used routinely for clinical examination; however, a patient's head position is random during cone-beam computed tomography (CBCT) acquisition. To solve this problem, we developed an accelerometer to record patients' NHP and reproduce them for CBCT images. In this study, we also tested the accuracy and reproducibility of our accelerometer. Materials and Methods: A total of 15 subjects participated in this study. We invented an accelerometer that measured acceleration on three axes and that could record roll and pitch calculations. Recorded roll and pitch data for each NHP were applied to a reoriented virtual image using three-dimensional (3D) imaging software. The data between the 3D models and the clinical photos were statistically analyzed side by side. Paired t-tests were used to statistically analyze the measurements. Results: The average difference in the angles between the clinical photograph and the 3D model was $0.04^{\circ}$ for roll and $0.29^{\circ}$ for pitch. The paired t-tests for the roll data (P=0.781) and the pitch data (P=0.169) showed no significant difference between the clinical photographs and the 3D model (P>0.05). Conclusion: By overcoming the limitations of previous NHP-recording techniques, our new method can accurately record patient NHP in a time-efficient manner. Our method can also accurately transfer the NHP to a 3D virtual model.

• Journal of Yeungnam Medical Science
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• v.2 no.1
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• pp.271-279
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• 1985

The authors treated a case of bimaxillary dentoalveolar protrusion corrected by anterior segmental osteotomies: As presurgical treatment & process, closing of the upper anterior spacing with fixed appliances was worked out, cephalometric predicition & model surgery was done, and fabrication of intra-arch acrylic resin splints were made. It was not necessary to make an intermaxillary fixation with wire after surgery. Only intramaxillary fixation of anterior retracted mobile segment with resin plate was required for 8 weeks. After surgical treatment, leveling of the upper and lower arch with rectangular arch wire were accomplished as the Intrusion of anterior teeth proceeded. We will continue to improve the class II molar relationship by using class II elastics and have a good occlusiion through the orthodontic treatment.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.2
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• pp.103-113
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• 2002

Distraction osteogenesis is a biologic process of new bone formation between the surfaces of bone segments that are gradually separated by incremental traction. Distraction osteogenesis is clinically applied as a new treatment modality of mandibular hypoplasia or bony defect area in maxillofacial area by many studies of distraction devices and method. But, disadvantages of distraction osteogenesis shows unfavorably long consolidation period and relapse tendency. Therefore, this experiment was designed to investigate the effectiveness of combined application of distraction and compression force for improving of bone quality and shortening of treatment period during distraction osteogenesis. Twenty-five Sprague-Dawley rats with $300{\sim}350gm$ were used. These were divided into two group as distraction group and combination group. The distraction group was added with conventional method during distraction osteogenesis, but the combination group was applied with compression force in the consolidation period. The rats were sacrificed for gross finding, radiographic and histologic findings at 3, 6 weeks after distraction. The results were as follow: 1. On radiographic finding, all combination of distraction and compression force group appeared more radiopacity than distraction group both at 3 weeks and 6 weeks after distraction group. 2. On histologic finding, the formation of mature lamellar bone were showed increasingly in combined group at 6weeks after distraction group. From this study, we may suggest that compression force application in consolidation period during distraction osteogenesis can be useful method to improve bone quality and to shorten the treatment period. But more experimental and clinical studies is necessitated on ideal application timing and method of compression force application during distraction osteogenesis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.5
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• pp.435-441
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• 2001

Orthognathic surgery for the correction of dentofacial deformities is a common elective procedure. That has proven over the years to be a safe operation with minimal long-term morbidity. But, there are many surgical complication including mal-union of the bone, TMJ problem, excessive bleeding, and permanent damage of inferior alveolar nerve. Among them excessive bleeding which focus is not clear is one of the serious complication because that is fatal and so a transfusion is performing for the prevention and management of that. Until the end of the 1980's, homologous blood transfusions were routinely necessary because of the large amounts of blood lost during surgery. Recently several blood-saving measures can be undertaken for orthognathic surgery patients before, during, and after the operation. We made a comparative study of an amount of blood loss, hematologic change and transfusion requirements based on a series of 40 consecutive patients undergoing single-jaw and double-jaw surgery. The purpose of this investigation was to make a comparative analysis of an amount of blood loss, post-operative hematologic change and duration of the procedure under induced hypotensive anesthesia in healthy orthognathic patients.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.2
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• pp.95-102
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• 2002

DM is a systemic disease with many complications. One of them, diabetic osteopenia is important sequelae and many authors reported reduced bone mass in diabetic rats. However, in mandible, study has been rare because of its anatomical limits. So the objective of this study was to investigate bony change in mandible of diabetic rats. Thirty-two adult rats were used in this study. Half of them were male and female respectively. In sixteen rats, streptozotocin was injected intraperitoneally to induce DM and the serum glucose concentration was checked to ensure the induction of DM prior to the time of sacrifice. At 1, 2, 3, 4, 6, 8, 12, 16weeks, control group and diabetic group rats were sacrificed respectively. And then bone mineral density of mandibles and femurs of the rats was measured using dual energy X-ray absorptiometry(DEXA). In addition serum osteocalcin and urine deoxypyridinoline were measured as markers of bone formation and resoption respectively. Mandibular and femoral bone density in streptozotocin induced rats was decreased with significance statistically after 4 weeks from injection. In mandible, comparing with femur, bone density was moderately decreased. The alveolar bone in mandible was more decreased bone density than the whole body in the mandible From these results, bone mineral density decreased in uncontrolled diabetic group with time, and especially alveolar bone was more destructive in the mandible. So authors think that consideration of reduced bone mineral density is necessary in dental procedure.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.5
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• pp.417-422
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• 2001

Objective: In many TMD cases, deformed and reduced condyle heads were frequently observed. This study was prepared to compare the dimensions between normal and symptomatic condyles, using MR images. Materials: One hundred and twenty one patients with clinical signs and MRI-confirmed diagnosis of disc displacement were selected for this study. Thirty eight TMJs from nineteen asymptomatic volunteers who had no clinical symptoms and no disc displacement on sagittal and coronal view of MRI, were served as normal. Methods: Symptomatic condyles were classified according to the severity of the anterior disc displacement. The amount of anterior disc displacement was evaluated at sagittal section, and they were classified into 4 groups as normal(N), little(G0), mild(G1), moderate(G2) and severe displacement(G3). The dimentions of condyle were measured at the 200% magnified view, by digitizing program. All dimensions were compared among each groups on the central section of sagittal and coronal views, and the statistical analysis was performed. Results: The mean value of anteroposterior length of normal condyle was $0.79{\pm}0.13cm$ at sagittal section and mediolateral length was $2.12{\pm}0.22cm$ on coronal section. The mean value of anteroposterior length of symptomatic condyle was $0.67{\pm}0.16cm$ at sagittal section and mediolateral length was $1.97{\pm}0.28cm$ on coronal section. Conclusions: The size of symptomatic condyle was smaller than normal TMJ. The size of condyle was decreased as the amount of the disc displacement was increased. The dimensional change was found on the anterior articular surface of condyle at the mild or moderate disc displacement. And at the case of severe disc displacement, dimensional change was found on the superior articular surface.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.5
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• pp.397-403
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• 2001

Purpose: The purpose of this study was to evaluate the postoperative stability of LeFort I osteotomy in two-jaw surgery of skeletal class III malocclusion and to help the establishment of treatment planning in patients with a skeletal class III malocclusion in the future. Materials and Methods: The lateral cephalograms of 14 patients who had been underwent two-jaw surgery via one-piece LeFort I osteotomy were traced and the landmarks were identified. Repeated tracings and construction of reference planes were done. Comparisons were made from the immediate postoperative to late postoperative results of each landmarks on the horizontal and vertical directions. Conclusions: 1. The horizontal changes of landmark ANS, point A, PNS and Mx6Rt between immediate postoperative to late postoperative data were statistically insignificant(p>0.05). 2. The vertical changes of landmark ANS, point A, PNS, Mx6Cr and Mx6Rt between immediate postoperative to late postoperative data were statistically insignificant(p>0.05). 3. The horizontal change of landmark Mx6Cr between immediate postoperative to late postoperative data was statistically significant(p<0.05). 4. Results showed that it was stable that one-piece LeFort I osteotomy in two-jaw surgery of skeletal class III malocclusion.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.5
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• pp.423-427
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• 2001

Objective: This study was prepared to figure out a certain dimension and morphology of the condyle at the central, medial and lateral aspects on MR images of asymptomatic volunteers, which could be comparable with those of the TMD patients' condyle. Materials: Sixty TMJs from 30 asymptomatic volunteers(15 male, 15 female) who had no clinical symptoms and no disc displacement on sagital and coronal view of MRI were served as normal. Method: MR images were taken from the asymptomatic volunteers and the dimension of the anteroposterior length, mediolateral width, height, convexities were measured through the images on the sagittal and coronal sections of mandibular condyle. Then, these data were collected and analyzed. Result: The mean value of anteroposterior length was $8.00{\pm}1.21mm$ at central section and mediolateral length was $21.40{\pm}2.32mm$ on coronal view. The anterior condylar length at medial side was the shortest and the convexity of anterior slop at the lateral side was proved to be the flattest among 3 sections. There were little dimensional and morphological differences at sagittal sections, but the mediolateral width of condyle at coronal section was significantly different between male and female. Conclusion: In sagittal sections, the anterior condyle length was shortest at medial side and the convexity of anterior slop was flattest at lateral side, and there were little dimensional and morphologic differences between male and female. In coronal section, male's condyle was more wider and flatter than female's.