• Journal of Korean Neurosurgical Society
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• v.38 no.3
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• pp.202-205
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• 2005

Objective : The purpose of this study is to measure the dimensions of foramen ovale and to localize the zygomatic point using computed tomography[CT] in Korean adults with idiopathic trigeminal neuralgia. Methods : Facial axial CT scans using the orbitomeatal plane were performed in 67patients [39males and 28females; mean age 58.8years] with idiopathic classic trigeminal neuralgia. We measured the size of the foramen ovale and localized the zygomatic point which was a skin marker over the ipsilateral zygoma that approximates the lateral projection of a straight line joining the centers of the two foramen ovale. Results : The axial dimensions of the foramen ovale on the orbitomeatal plane were of average length : $8.18{\pm}0.82mm$ [range $6.9{\sim}11.5mm$]. width : $4.06{\pm}0.86mm$ [$2.5{\sim}5.7mm$]. The average distance between the external acoustic meatus and the zygomatic point was $21.64{\pm}1.99mm$ [$16.3{\sim}25.0mm$] and the average distance of anterior margin of condylar process of mandible to zygomatic point was $4.29{\pm}1.19mm$ [$1.0{\sim}7.0mm$]. Conclusion : The anatomical understandings including the size of the foramen ovale and localization of the zygomatic point could be helpful in determining a plan of percutaneous approaches to foramen ovale.

• Structural Engineering and Mechanics
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• v.68 no.5
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• pp.603-619
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• 2018

In this research, an effective computational technique is carried out for nonlinear and post-buckling analyses of cracked imperfect composite plates. The laminated plates are assumed to be moderately thick so that the analysis can be carried out based on the first-order shear deformation theory. Geometric non-linearity is introduced in the way of von-Karman assumptions for the strain-displacement equations. The Ritz technique is applied using Legendre polynomials for the primary variable approximations. The crack is modeled by partitioning the entire domain of the plates into several sub-plates and therefore the plate decomposition technique is implemented in this research. The penalty technique is used for imposing the interface continuity between the sub-plates. Different out-of-plane essential boundary conditions such as clamp, simply support or free conditions will be assumed in this research by defining the relevant displacement functions. For in-plane boundary conditions, lateral expansions of the unloaded edges are completely free while the loaded edges are assumed to move straight but restricted to move laterally. With the formulation presented here, the plates can be subjected to biaxial compressive loads, therefore a sensitivity analysis is performed with respect to the applied load direction, along the parallel or perpendicular to the crack axis. The integrals of potential energy are numerically computed using Gauss-Lobatto quadrature formulas to get adequate accuracy. Then, the obtained non-linear system of equations is solved by the Newton-Raphson method. Finally, the results are presented to show the influence of crack length, various locations of crack, load direction, boundary conditions and different values of initial imperfection on nonlinear and post-buckling behavior of laminates.

• The korean journal of orthodontics
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• v.53 no.1
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• pp.35-44
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• 2023

Objective: Surgically assisted maxillary protraction is an alternative protocol in severe Class III cases or after the adolescent growth spurt involving increased maxillary advancement. Correction of the maxillary deficiency has been suggested to improve pharyngeal airway dimensions. Therefore, this retrospective study aimed to analyze the airway changes cephalometrically following surgically assisted maxillary protraction with skeletal anchorage and Class III elastics. Methods: The study population consisted of 15 Class III patients treated with surgically assisted maxillary protraction combined with skeletal anchorage and Class III elastics (mean age: 12.9 ± 1.2 years). Growth changes were initially assessed for a mean of 5.5 ± 1.6 months prior to treatment. Airway and skeletal changes in the control (T0), pre-protraction (T1), post-protraction (T2), and follow-up (T3) periods were monitored and compared using lateral cephalometric radiographs. Statistical significance was set at p < 0.05. Results: The skeletal or airway parameters showed no statistically significant changes during the control period. Sella to nasion angle, N perpendicular to A, Point A to Point B angle, and Frankfort plane to mandibular plane angle increased significantly during the maxillary protraction period (p < 0.05), but no significant changes were observed in airway parameters (p > 0.05). No statistically significant changes were observed in the airway parameters in the follow-up period either. However, Sella to Gonion distance increased significantly (p < 0.05) during the follow-up period. Conclusions: No significant changes in pharyngeal airway parameters were found during the control, maxillary protraction, and follow-up periods. Moreover, the significant increases in the skeletal parameters during maxillary protraction were maintained in the long-term.

• The korean journal of orthodontics
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• v.53 no.2
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• pp.125-136
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• 2023

Before progress was recently made in the application of temporary anchorage devices (TADs) in bio-mechanical design, orthodontists were rarely able to intrude molars to reduce upper posterior dental height (UPDH). However, TADs are now widely used to intrude molars to flatten the occlusal plane or induce counterclockwise rotation of the mandible. Previous studies involving clinical or animal histological evaluation on changes in periodontal conditions after molar intrusion have been reported, however, studies involving human histology are scarce. This case was a Class I malocclusion with a high mandibular plane angle. Upper molar intrusion with TADs was performed to reduce UPDH, which led to counterclockwise rotation of the mandible. After 5 months of upper molar intrusion, shortened clinical crowns were noticed, which caused difficulties in oral hygiene and hindered orthodontic tooth movement. The mid-treatment cone-beam computed tomography revealed redundant bone physically interfering with buccal attachment and osseous resective surgeries were followed. During the surgeries, bilateral mini screws were removed and bulging alveolar bone and gingiva were harvested for biopsy. Histological examination revealed bacterial colonies at the bottom of the sulcus. Infiltration of chronic inflammatory cells underneath the non-keratinized sulcular epithelium was noted, with abundant capillaries being filled with red blood cells. Proximal alveolar bone facing the bottom of the gingival sulcus exhibited active bone remodeling and woven bone formation with plump osteocytes in the lacunae. On the other hand, buccal alveolar bone exhibited lamination, indicating slow bone turnover in the lateral region.

• Archives of Plastic Surgery
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• v.51 no.1
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• pp.52-61
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• 2024

Background Although prepectoral implant-based breast reconstruction has recently gained popularity, dual-plane reconstruction is still a better option for patients with poor-quality mastectomy skin flaps. However, shoulder morbidity is aggravated by subpectoral reconstruction, especially in irradiated patients. This study aimed to demonstrate shoulder exercise improvement in subpectoral reconstruction by delayed prepectoral conversion with an acellular dermal matrix (ADM) inlay graft technique at the time of expander-to-implant exchange after irradiation. Methods Patients with breast cancer treated for expander-to-implant exchange after subpectoral expander insertion and subsequent radiotherapy between January 2021 and June 2022 were enrolled. An ADM inlay graft was inserted between the pectoralis major muscle and the previously inserted ADM. The ADM was sutured partially overlapping the pectoralis muscle from the medial side with the transition part, to the muscle border at the lateral side. Perioperative shoulder joint active range-of-motion (ROM) for forward flexion, abduction, and external rotation was also evaluated. Results A total of 35 patients were enrolled in the study. Active shoulder ROM significantly improved from 163 degrees preoperatively to 176 degrees postoperatively in forward flexion, 153 to 175 degrees in abduction, and 69 to 84 degrees in external rotation. There was no difference in patient satisfaction regarding the final outcome between the conventional prepectoral reconstruction group and the study group. Conclusion Shoulder exercises in irradiated patients who underwent subpectoral reconstruction were improved by delayed prepectoral conversion using an ADM inlay graft. It is recommended that subpectoral reconstruction not be ruled out due to concerns regarding muscle contracture and shoulder morbidity in radiation-planned patients with poor mastectomy skin flaps.

• The korean journal of orthodontics
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• v.54 no.5
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• pp.316-324
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• 2024

Objective: To evaluate tooth displacement and periodontal stress generated by the dual action vertical intra-arch technique (DAVIT) for open-bite correction using three-dimensional finite element analysis. Methods: A three-dimensional model of the maxilla was created by modeling the cortical bone, cancellous bone, periodontal ligament, and teeth from the second molar to the central incisor of a hemiarch. All orthodontic devices were designed using specific software to reproduce their morpho-dimensional characteristics, and their physical properties were determined using Young's modulus and Poisson's coefficient of each material. A linear static simulation was performed to analyze the tooth displacements (mm) and maximum stresses (Mpa) induced in the periodontal ligament by the posterior intrusion and anterior extrusion forces generated by the DAVIT. Results: The first and second molars showed the greatest intrusion, whereas the canines and lateral incisors showed the greatest extrusion displacement. A neutral zone of displacement corresponding to the fulcrum of occlusal plane rotation was observed in the premolar region. Buccal tipping of the molars and lingual tipping of the anterior teeth occurred with intrusion and extrusion, respectively. Posterior intrusion generated compressive stress at the apex of the buccal roots and furcation of the molars, while anterior extrusion generated tensile stress at the apex and apical third of the palatal root surface of the incisors and canines. Conclusions: DAVIT mechanics produced a set of beneficial effects for open-bite correction, including molar intrusion, extrusion and palatal tipping of the anterior teeth, and occlusal plane rotation with posterior teeth uprighting.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.3
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• pp.153-159
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• 2013

Purpose: Nowadays, checkbite methods and a digital sensor are used to analyze the movement of mandible. However, there are no study comparing two methods. Therefore, this study has compared measuring the condylar inclination methods by using the new ARCUSdigma 2 system and the checkbite method. Materials and methods: Young 20 adults without any orthodontic treatment experiences, missing teeth, and restorations with the change of occlusal plane were tested. Angles of condylar path were measured 3 times each, based on Camper's line, by using two methods. KaVo PROTAR Evo 7 semi-adjustable articulator was used and the data were statistically analyzed. Results: 1. The anterior sagittal condylar inclination by ARCUSdigma 2 system were measured as $26.97^{\circ}({\pm}7.38^{\circ})$ on the left side and $29.80^{\circ}({\pm}8.19^{\circ})$ on the right side. The lateral condylar inclination were measured as $5.75^{\circ}({\pm}3.47^{\circ})$ on the left side and $8.10^{\circ}({\pm}4.98^{\circ})$ on the right side. 2. The anterior sagittal condylar inclination by checkbite method were measured as $25.20^{\circ}({\pm}6.53^{\circ})$ on the left side and $28.18^{\circ}({\pm}7.38^{\circ})$ on the right side. The lateral condylar inclination were measured as $10.97^{\circ}({\pm}5.63^{\circ})$ on the left side and $12.03^{\circ}({\pm}5.22^{\circ})$ on the right side. There was no statistically significant difference between male and female (P>.05). 3. The lateral condylar inclinations of ARCUSdigma 2 were statistically significantly smaller than that of checkbite method (P<.05). Conclusion: In Both of 2 methods, there was no statistically significant difference between male and female (P>.05). However, the lateral condylar inclinations of ARCUSdigma 2 were statistically significantly smaller than that of checkbite method (P<.05).

• Journal of the Korean Arthroscopy Society
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• v.5 no.2
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• pp.69-73
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• 2001

Purpose : To evaluate the clinical results and widening of bony tunnel after anterior cruciate ligament(ACL) reconstruction using hamstring tendon with Ligament Anchor(LA) screw, which is newly designed fur fixation of graft into femur. Materials and Methods : Fifty eight patients who were followed up at least more than 2 years after ACL reconstruction with four strands of Hamstring tendon were included in this study. The graft was fixed with LA screw at femoral tunnel and with bioabsorbable interference screw at tibial tunnel. The average period of follow-up was 28 months. The clinical results such as physical examination and Lysholm knee score and radiological results. widening of bony tunnel and instrumented anterior laxity test with $Telos^{\circledR}$(Telos stress device; Austin & Associates, Inc., Polston, US) were evaluated. Results . The Lysholm knee score was 60.0 in average preoperatively and improved to 94.0 in average at follow up. On the Lachman test, there were mild(+) instability in 16 cases, moderate(++) in 24, severe(+++) in 18 preoperatively. 50 cases were converted to negative and 8 to mild instability at follow up. On instrumented anterior laxity test with $Telos^{\circledR}$, side to side difference in 20 lb was 12.9mm in average preoperatively, and was decreased to 3.1mm in average follow-up. The femoral tunnel was widened from 10.6mm postoperatively to 12.7mm$(21.1\%)$ at follow up on antero-posterior plane and from 10.7mm to 12.4mm$(16.5\%)$ on lateral plane. Tibial tunnels was also widened from 9.8mm to 11.8mm$(20.7\%)$ on antero-posterior plane and from 9.9mm to 11.7mm$(18.9\%)$ in lateral plane. Conclusion : ACL reconstruction with hamstring tendon and LA screw was one of the choice of grafts and fixatives in restoring knee stability and in improving clinical results with little complications such as excessive widening of bony tunnel.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.28 no.2
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• pp.363-385
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• 1998

In orthodontics and orthognathic surgery. cephalogram has been routine practice in diagnosis and treatment evaluation of craniofacial deformity. But its inherent distortion of actual length and angles during projecting three dimensional object to two dimensional plane might cause errors in quantitative analysis of shape and size. Therefore, it is desirable that three dimensional object is diagnosed and evaluated three dimensionally and three dimensional CT image is best for three dimensional analysis. Development of clinic necessitates evaluation of result of treatment and comparison before and after surgery. It is desirable that patient that was diagnosed and planned by three dimensional computed tomography before surgery is evaluated by three dimensional computed tomography after surgery. too. But Because there is no standardized normal values in three dimension now and three dimensional Computed Tomography needs expensive equipments and because of its expenses and amount of exposure to radiation. limitations still remain to be solved in its application to routine practice. If postoperative three dimensional image is constructed by pre and postoperative lateral and postero-anterior cephalograms and preoperative three dimensional computed tomogram. pre and postoperative image will be compared and evaluated three dimensionally without three dimensional computed tomography after surgery and that will contribute to standardize normal values in three dimension. This study introduced new method that computer-simulated three dimensional image was constructed by preoperative three dimensional computed tomogram and pre and postoperative lateral and postero-anterior cephalograms. and for validation of new method. in four cases of dry skull that position of mandible was displaced and four patients of orthognathic surgery. computer-simulated three dimensional image and actual postoperative three dimensional image were compared. The results were as follows. 1. In four cases of dry skull that position of mandible was displaced. range of displacement between computer-simulated three dimensional images and actual postoperative three dimensional images in co-ordinates values was from -1.8 mm to 1.8 mm and 94％ in displacement of all co-ordinates values was from -1.0 mm to 1.0 mm and no significant difference between computer-simulated three dimensional images and actual postoperative three dimensional images was noticed(p>0.05). 2. In four cases of orthognathic surgery patients, range of displacement between computer­simulated three dimensional images and actual postoperative three dimensional images in coordinates values was from -6.7 mm to 7.7 mm and 90％ in displacement of all co-ordinates values was from -4.0 to 4.0 mm and no significant difference between computer-simulated three dimensional images and actual postoperative three dimensional images was noticed(p>0.05). Conclusively. computer-simulated three dimensional image was constructed by preoperative three dimensional computed tomogram and pre and postoperative lateral and postero-anterior cephalograms. Therefore. potentiality that can construct postoperative three dimensional image without three dimensional computed tomography after surgery was presented.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.185-194
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• 2001

This study was designed to evaluate the effects of angulation changes of head posture on the enlargement ratios of a lateral headfilm depending on the vortical or horizontal rotation of the objects. A device was constructed to measure regional changes of enlargement ratios. The device was held within the cephalostat and cephalograms recorded at each measured degrees of the device tilting, vertically and horizontally. The enlargement ratios of the horizontal, vertical, and angular measurements on the films taken at each tilted angulations were obtained and compared with those on the films taken without rotation. In summary, the enlargement ratios of the horizontal linear measurements were decreased during horizontal rotations. The enlargement ratios of vortical measurements of the right side on the film were increased and those of the left side were decreased by the horizontal rotations. Enlargement ratios of horizontal measurements were affected further than those of vertical measurements by the same angular changes of the horizontal rotations. Therefore, a disruption of parallelism between the object's midsagittal plane and the film could result in distortion of the image while vertical rotation around the object's porionic axis would not significantly affect the enlargement ratios on the headfilm.