• Maxillofacial Plastic and Reconstructive Surgery
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• v.14 no.4
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• pp.327-339
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• 1992

This study was undertaken to investigate the effect of orthognathic surgery on occlusal force. The maximum bite force was measured in 26 dentofacial deformity patients, aged 14-26(mean age 20.3) years, before surgery and at IMF removal, 3, 6, and 12months postsurgery. To grope the correlation of bite force and skeletal change after orthognathic surgery, the cephalometric headplates were measured, tabulated and statistically analyzed. The results were as follows. 1. The presurgical maximum bite force was 13.7kg in upper first molar(rt. Side 12.7kg, it. Side 14.6kg). There was remarkable difference with that of normal occlusion. 2. The recovery of bite force was very significant in according to the operation method and the duration of IMF that was 7.6kg at IMF removal, 14.2kg at 3 months, 19.7kg at 6 months. 26.1kg at 12 months postsurgery. 3. To fasten the recovery and to increase the bite force after orthognathic surgery, the long IMF time and the injury to the masticatory muscle should be avoided by the internal rigid fixation and early physical exercise. 4. The bite force was positively correlated to the changes of mandibular plane angle, the angle between platatal plane and mandibular plan, the angle between occlusal plane and mandibular plane, and negatively correlated to the changes of mandibular body length in craniofacial structure. 5. There was no correlationship between bit force and mesial inclination of tooth long axis of first molar in this subject. 6. There was no correlation between the changes of bite force and the changes of mechanical advantage of the temporal and masseter muscle.

• International Journal of Oral Biology
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• v.43 no.2
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• pp.101-111
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• 2018

Understanding the classification of malocclusion is a crucial issue in Orthodontics. It can also help us to diagnose, treat, and understand malocclusion to establish a standard for definite class of patients. Principal component analysis (PCA) and k-means algorithms have been emerging as data analytic methods for cephalometric measurements, due to their intuitive concepts and application potentials. This study analyzed the macro- and meso-scale classification structure and feature basis vectors of 1020 (415 male, 605 female; mean age, 25 years) orthodontic patients using statistical preprocessing, PCA, random matrix theory (RMT) and k-means algorithms. RMT results show that 7 principal components (PCs) are significant standard in the extraction of features. Using k-means algorithms, 3 and 6 clusters were identified and the axes of PC1~3 were determined to be significant for patient classification. Macro-scale classification denotes skeletal Class I, II, III and PC1 means anteroposterior discrepancy of the maxilla and mandible and mandibular position. PC2 and PC3 means vertical pattern and maxillary position respectively; they played significant roles in the meso-scale classification. In conclusion, the typical patient profile (TPP) of each class showed that the data-based classification corresponds with the clinical classification of orthodontic patients. This data-based study can provide insight into the development of new diagnostic classifications.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.157-157
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• 2017

Titanium and its alloys that have a good biocompatibility, corrosion resistance, and mechanical properties such as hardness and wear resistance are widely used in dental and orthopedic implant applications. They can directly connect to bone. However, they do not form a chemical bond with bone tissue. Plasma electrolytic oxidation (PEO) that combines the high voltage spark and electrochemical oxidation is a novel method to form ceramic coatings on light metals such as titanium and its alloys. This is an excellent reproducibility and economical, because the size and shape control of the nano-structure is relatively easy. Silicon (Si), manganese (Mn), and magnesium (Mg) has a useful to bone. Particularly, Si has been found to be essential for normal bone, cartilage growth and development. Manganese influences regulation of bone remodeling because its low content in body is connected with the rise of the concentration of calcium, phosphates and phosphatase out of cells. Insufficience of Mn in human body is probably contributing cause of osteoporosis. Pre-studies have shown that Mg plays very important roles in essential for normal growth and metabolism of skeletal tissue in vertebrates and can be detected as minor constituents in teeth and bone. The objective of this work was to study nucleation and growth of bone-like apatite formation on Ti-6Al-4V in solution containing Mn, Mg, and Si ions after plasma electrolytic oxidation. Anodized alloys was prepared at 270V~300V voltages. And bone-like apatite formation was carried out in SBF solution for 1, 3, 5, and 7 days. The morphologies of PEO-treated Ti-6Al-4V alloy in containing Mn, Mg, and Si ions were examined by FE-SEM, EDS, and XRD.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.80-80
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• 2017

Titanium and its alloys that have a good biocompatibility, corrosion resistance, and mechanical properties such as hardness and wear resistance are widely used in dental and orthopedic implant applications. However, they do not form a chemical bond with bone tissue. Plasma electrolytic oxidation (PEO) that combines the high voltage spark and electro-chemical oxidation is a novel method to form ceramic coatings on light metals such as tita-nium and its alloys. This is an excellent re-producibility and economical, because the size and shape control of the nano-structure is relatively easy. Silicon (Si), manganese (Mn), and magne-sium (Mg) have a useful to bone. Particularly, Si has been found to be essential for normal bone, cartilage growth, and development. Mn influences regulation of bone remodeling be-cause its low content in body is connected with the rise of the concentration of calcium, phosphates and phosphatase out of cells. Pre-studies have shown that Mg plays very im-portant roles in essential for normal growth and metabolism of skeletal tissue in verte-brates and can be detected as minor constitu-ents in teeth and bone. In this study, Electrochemical behavior of plasma electrolytic oxidized films formed in solution containing Mn, Mg and Si ions were researched using various experimental in-struments. A series of Si-Mn-Mg coatings are produced on Ti dental implant using PEO, with the substitution degree, respectively, at 5 and 10%. The potentiodynamic polarization and AC impedance tests for corrosion behav-iors were carried out in 0.9% NaCl solution at similar body temperature using a potentiostat with a scan rate of 1.67mV/s and potential range from -1500mV to + 2000mV. Also, AC impedance was performed at frequencies anging from 10MHz to 100kHz for corrosion resistance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.12
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• pp.1585-1591
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• 2011

In this paper, we present a new exoskeleton-type data glove that can sense the movement of the human finger and reflect the force to the finger. The data glove is designed on the basis of the skeletal structure of the human hand, and the finger module has 1 degree-of-freedom because it includes three four-bar mechanism joints in series and a wire-coupling mechanism. In addition, the transmission ratio of the finger module is maintained at 1:1.4:1 over the entire movement range, and hence, the module can perform both extension and flexion. In addition, to enable adduction/abduction motion of the human hand, a unique MCP joint is designed by using two universal joints. To validate the feasibility of the data glove, master-slave control experiments based on force-position control between the data glove and the robot hand are conducted.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.74-74
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• 2018

Ti-6Al-4V alloys have been widely used as orthopedic materials because of their excellent corrosion resistance and mechanical properties. However, it does not bind directly to the bone, so it requires a surface modification. This problem can be solved by nanotube and micropore formation. Plasma electrolytic oxidation (PEO) treatment for micropore, which combines high-voltage spark and electrochemical oxidation, is a new way of forming a ceramic coating on light metals such as titanium and its alloys. This method has excellent reproducibility and can easily control the shape and size of the Ti alloy. In this study, formation of bioactive surface by PEO-treatment after $2^{nd}$ ATO technique of Ti-6Al-4V alloy was invesgated by various instrument. Nanotube oxide surface structure was formed on the surface by anodic oxidation treatment in 0.8 wt.% NaF and 1M $H_3PO_4$ electrolytes. After nanotube formation, nanotube layer was removed by ultrasonic cleaning. PEO-treatment was carried out at 280V for 3 minutes in the electrolytic solution containing the bioactive substance (Mg, Zn, Mn, Sr, and Si). The surface of Ti-6Al-4V alloy was observed by field emission scanning electron microscopy (FE-SEM, S-4800 Hitachi, Japan). An energy dispersive X-ray spectrometer (EDS, Inca program, Oxford, UK) was used to analyze the spectra of physiologically active Si, Mn, Mg, Zn, and Sr ions. The PEO film formed on the Ti-6Al-4V alloy surface was characterized using an X-ray diffractometer (TF-XRD, X'pert Philips, Netherlands). It is confirmed that bioactive ions play an essential role in the normal bone growth and metabolism of the human skeletal tissues.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.529-539
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• 1998

The effects of membrane surface charge originated from lipid head groups on ion channels were tested by analyzing the activity of single large conductance $Ca^{2+}-activated\;K^+$ (maxi K) channel from rat skeletal muscle. The conductances and open-state probability ($P_o$) of single maxi K channels were compared in three types of planar lipid bilayers formed from a neutral phosphatidylethanolamine (PE) or two negatively-charged phospholipids, phosphatidylserine (PS) and phosphatidylinositol (PI). Under symmetrical KCl concentrations $(3{\sim}1,000\;mM)$, single channel conductances of maxi K channels in charged membranes were $1.1{\sim}1.7$ times larger than those in PE membranes, and the differences were more pronounced at the lower ionic strength. The average slope conductances at 100 mM KCl were $251{\pm}9.9$, $360{\pm}8.7$ and $356{\pm}12.4$ $(mean{\pm}SEM)$ pS in PE, PS and PI membranes respectively. The potentials at which $P_o$ was 1/2, appeared to have shifted left by 40 mV along voltage axis in the membranes formed with PS or PI. Such shift was consistently seen at pCa 5, 4.5, 4 and 3.5. Estimation of the effect of surface charge from these data indicated that maxi K channels sensed the surface potentials at a distance of $8{\sim}9\;{\AA}$ from the membrane surface. In addition, similar insulation distance ($7{\sim}9\;{\AA}$) of channel mouth from the bilayer surface charge was predicted by a 3-barrier-2-site model of energy profile for the permeation of $K^+$ ions. In conclusion, despite the differences in structure and fluidity of phospholipids in bilayers, the activities of maxi K channels in two charged membranes composed of PS or PI were strikingly similar and larger than those in bilayers of PE. These results suggest that the enhancement of conductance and $P_o$ of maxi channels is mostly due to negative charges in the phospholipid head groups.

• Imaging Science in Dentistry
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• v.36 no.2
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• pp.95-101
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• 2006

Purpose : Bony strength is dependent on bone mass and bony structure. So this study was designed to investigate the relationship between the bone mass and bony trabecular characteristics. Subjects and Methods : Study subjects were 51 females (average age 68.6 years) and 20 males (average age 66.4 years). Bone mineral density (BMD, $grams/cm^2$) of proximal femur was measured by a dual energy X-ray absorptiometry (DEXA). Regions of interest (ROIs) were selected from the digitized radiographs of proximal femur. A customized computer program processed morphologic operations (MO) of ROIs. 44 skeletal variables of MO were calculated from ROIs on the Ward's triangle and greater trochanter of femur. WHO BMD classes were predicted by MO variables of the same ROI. Classification and Regression Tree analysis was used for calculating weighted kappa values, sensitivity and specificity of MO. Results : The discriminating factors of morphologic operation were branch point, branch point [per cm sq]. Age also played important role in distinguishing osteoporotic classes. The sensitivity of MO at Ward's triangle and Greater Trochanter was 91.8%, 65.6%, respectively. The specificity of MO was 100% at Ward's triangle and Greater Trochanter. Conclusion : Bony trabecular characteristics obtained using radiological bone morphometric analysis seem to be related to bone mass.

• Bulletin of the Korean Chemical Society
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• v.23 no.8
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• pp.1106-1109
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• 2002

Studies on subtle spacer ligand effects of AgCF3SO3 with 3,3'-Py2X (X = O vs S) have been carried out. The reaction of AgCF3SO3 with 3,3'-Py2O and 3,3'-Py2S produces [Ag(CF3SO3)(3,3'-Py2O)] and [Ag(3,3'-Py2S)] (CF3SO3), respectively. Crystallographic characterization of [Ag(CF3SO3)(3,3'-Py2O)] (monoclinic P1, a =8.405(2) $\AA$, b = 10.714(2) $\AA$, c = 18.031(2) $\AA$, $\alpha=$ 77.36(2), $\beta=107.83(2)^{\circ}$, $\gamma=$ 66.92(2), V = 1438.0(5) $\AA3$ , Z =2,R = 0.0486) reveals that the skeletal structure is an anion-bridged double-strand. The double-strands are packed like a plywood. The framework of [Ag(3,3'-Py2S)](CF3SO3) (orthorhombic Pcab, a = 17.330(2) $\AA$, b = 8.640(1) $\AA$, c = 19.933(6) $\AA$, V = 2985(1) $\AA3$ , Z =8, R = 0.0437) is a sinusoidal single-strand. The formation of each coordination polymer appears to be primarily associated with the donating ability and the confor ma-tional energy barrier of the spacer ligands. Thermal analyses indicate that [Ag(CF3SO3)(3,3'-Py2O)] and [Ag(3,3'-Py2S)](CF3SO3) are stable up to 250 $^{\circ}C$ and 210 $^{\circ}C$, respectively. For the anion exchangeability, the nature of the spacer ligand is more significant factor than the distance of silver(Ⅰ)···triflate.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.181-184
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• 2002

Currently, the lack of equipments for the medical practice and education made it impossible for the people in medical institution to carry out suitable experiments for observing human bodies. In this paper, the authors embodied three dimensional images and moving pictures for the human skeletal structure, digestive organs, cardiovascular system and their processes over the internet framework. The three dimensional images and moving picture made it possible for the general people as well as the specialists to observe and obtain informations with regard to the human body. specially, the authors realized a framework for visualizing the human bodies in three dimensional images, via which a detailed and realistic architecture for the human body and its organs tan be obtained. The system developed in this paper can be used in the practice and education of the people engaged in medical fields.