• The korean journal of orthodontics
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• v.39 no.4
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• pp.203-212
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• 2009

Objective: The aim of this study was to evaluate the strain induced in the cortical bone surrounding an orthodontic microimplant during insertion in a self-drilling manner. Methods: A 3D finite element method was used to simulate the insertion of a microimplant (AbsoAnchor SH1312-7, Dentos Co., Daegu, Korea) into 1 mm thick cortical bone. The shape and dimension of thread groove in the center of the cortical bone produced by the cutting flute at the apical of the microimplant was obtained from animal test using rabbit tibias. A total of 3,600 analysis steps was used to calculate the 10 turns and 5 mm advancement of the microimplant. A series of remesh in the cortical bone was allowed to accommodate the change in the geometry accompanied by the implant insertion. Results: Bone strains of well higher than 4,000 microstrain, the reported upper limit for normal bone remodeling, were observed in the peri-implant bone along the whole length of the microimplant. Level of strains in the vicinity of either the screw tip or the valley part were similar. Conclusions: Bone strains from a microimplant insertion in a self-drilling manner might have a negative impact on the physiological remodeling of cortical bone.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.11
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• pp.1081-1090
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• 2012

This study aims to track the longitudinal alteration pattern on the trabecular bone microarchitecture at tibial epiphysis induced by T-OA over time using in vivo micro computed tomography (${\mu}CT$). Ten SD rats were divided into control (n = 5) and T-OA (n = 5) groups. Anterior cruciate ligament transaction was performed for the T-OA group. The results showed that the alteration pattern on the trabecular bone microarchitecture at tibial epiphysis in the T.OA group was definitely different compared with that in the CON group from 0 to 8 weeks (approximately 4-16%, P > 0.05). In particular, a difference was observed in the bone formation and density distributions over time (from 0 or 4 to 8 weeks; approximately 5.15%, P < 0.05). An improved understanding of the alteration pattern on the trabecular bone microarchitecture at tibial epiphysis may assist in developing more targeted treatment interventions for T-OA.

• Restorative Dentistry and Endodontics
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• v.33 no.6
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• pp.570-579
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• 2008

The purpose of this study was to investigate the distribution of tensile stress of canal obturated maxillary second premolar with access cavity and notch-shaped class V cavity restored with composite resin using a 3D finite element analysis. The tested groups were classified as 8 situations by only access cavity or access cavity with notch-shaped class V cavity (S or N), loading condition (L1 or L2), and with or without glass ionomer cement base (R1 or R2). A static load of 500 N was applied at buccal and palatal cusps. Notch-shaped cavity and access cavity were filled microhybrid composite resin (Z100) with or without GIC base (Fuji II LC). The tensile stresses presented in the buccal cervical area, palatal cervical area and occlusal surface were analyzed using ANSYS. Tensile stress distributions were similar regardless of base. When the load was applied on the buccal cusp, excessive high tensile stress was concentrated around the loading point and along the central groove of occlusal surface. The tensile stress values of the tooth with class Ⅴ cavity were slightly higher than that of the tooth without class V cavity. When the load was applied the palatal cusp, excessive high tensile stress was concentrated around the loading point and along the central groove of occlusal surface. The tensile stress values of the tooth without class V cavity were slightly higher than that of the tooth with class V cavity.

• Restorative Dentistry and Endodontics
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• v.34 no.1
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• pp.69-79
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• 2009

The purpose of this study was to evaluate the influence of elastic modulus of restorative materials and the number of interfaces of post and core systems on the stress distribution of three differently restored endodontically treated maxillary second premolars using 3D FE analysis. Model 1, 2 was restored with a stainless steel or glass fiber post and direct composite resin. A PFG or a sintered alumina crown was considered. Model 3 was restored by EndoCrown. An oblique 500 N was applied on the buccal (Load A) and palatal (Load B) cusp. The von Mises stresses in the coronal and root structure of each model were analyzed using ANSYS. The elastic modulus of the definitive restorations rather than the type of post and core system was the primary factor that influenced the stress distribution of endodontically treated maxillary premolars. The stress concentration at the coronal structure could be lowered through the use of definitive restoration of high elastic modulus. The stress concentration at the root structure could be lowered through the use of definitive restoration of low elastic modulus.

• Journal of Korean Medicine Rehabilitation
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• v.25 no.2
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• pp.15-35
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• 2015

Objectives This study was performed to investigate the effects of Bujasasim-tang ethanol extract (BST) on oxidative stress, inflammation and osteoarthritic rat model. Methods To ensure safety of BST, heavy metal levels were measured and cytotoxicity test was done. In vitro, To evaluate antioxidative effects of BST, total phenolic contents, 1,1-diphenyl-2-picryl-hydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging activity, reactive oxygen species (ROS) levels were measured. Also, to evaluate anti-inflammatory effects of BST treated group, total nitric oxide (NO) and pro-inflammatory cytokines (IL-$1{\beta}$, IL-6, TNF-${\alpha}$) levels were measured in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. In vivo, We injected MIA $50{\mu}l$ (60 mg/ml) into knee joints of rats to induce osteoarthritis. Rats were divided into total 3 groups (normal, control, BST treated group, each n=7). Normal group was not treated at all without inducing osteoarthritis and taken normal diet. Control group was induced osteoarthritis by MIA and taken with 2 ml of distilled water once a day for 4 weeks. BST treated group was induced osteoarthritis by MIA and taken BST 2 ml (200 mg/kg/mouse) once a day for 4 weeks. We evaluated dynamic weight bearing with the Incapacitance Test Meter. At the end of experiment, the rats were sacrificed to observe the functions of liver and kidney, changes of WBC, neutrophil, lymphocyte, monocyte levels in blood, to evaluate the levels of pro-inflammatory cytokines, tissue inhibitor of metallopreteinases-1 (TIMP-1), matrix metalloproteinase-9 (MMP-9), prostaglandin $E_2$ ($PGE_2$), leukotriene $B_4$ ($LTB_4$) within serum. We observed change of articular structures by Hematoxylin & Eosin (H&E), safranin-O staining method and measured amount of cartilage by micro CT-arthrography. Statistical analysis was done by unpaired student's t-test with significance level at p<0.05 in SPSS 11.0 for windows. Results 1. Safety of the BST was identified. 2. AST, ALT, BUN, creatinine levels of BST treated group were within normal limit. In vitro, 1. DPPH and ABTS free radical scavenging activities of BST showed dose-dependent increase. 2. ROS production were significantly decreased. 3. Total nitric oxide (NO) and IL-$1{\beta}$ production were decreased. 4. IL-6 and TNF-${\alpha}$ production were significantly decreased. In vivo, 1. Weight bearing ability was significantly increased. 2. WBC, neutrophil, lymphocyte, monocyte levels in blood were decreased. 3. IL-$1{\beta}$ and TNF-${\alpha}$ levels in serum were significantly decreased. and the IL-6 level was decreased. 4. TIMP-1, MMP-9, $LTB_4$, $PGE_2$ levels in serum were significantly decreased. 5. Cartilage volume of BST treated group was significantly increased. Also changes of cartilage, synovial membrane, fibrous tissue were suppressed. Conclusions The results obtained in this study Bujasasim-tang have effects of antioxidative, anti-inflammatory, relieve pain and protection of cartilage. Therefore we expect that Bujasasim-tang is effective treatment for osteoarthritis.

• Restorative Dentistry and Endodontics
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• v.31 no.5
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• pp.359-370
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• 2006

The objective of this study was to investigate the effect of excessive occlusal loading on stress distribution on four type of cervical lesion, using a three dimensional finite element analysis (3D FEA). The extracted maxillary second premolar was scanned serially with Micro-CT. The 3D images were processed by 3D-DOCTOR. ANSYS was used to mesh and analyze 3D FE model. Four different lesion configurations representative of the various types observed clinically for teeth were studied. A static point load of 500N was applied to the buccal and lingual cusp (Load A and B). The principal stresses in lesion apex, and vertical sectioned margin of cervical wall were analyzed. The results were as follows 1. The patterns of stress distribution were similar but the magnitude was different in four types of lesion 2. The peak stress was observed at mesial corner and also stresses concentrated at lesion apex. 3. The compressive stress under load A and the tensile stress under load B were dominant stress. 4. Under the load, lesion can be increased and harmful to tooth structure unless restored.

• Journal of Korean Medicine Rehabilitation
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• v.25 no.4
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• pp.1-20
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• 2015

Objectives This study was intended to clarify the anti-inflammation and anti-oxidation effects of gamikyejakjimo-tang herbal acupuncture (GKHA) for osteoarthritis. Methods Osteoarthritis was induced by injection of MIA into right knee joint cavities of rats. Rats were divided into a total of 4 groups (n=8). The 4 groups were normal group, control group, positive comparison group and expeimental group. Indomethacin and GKHA were medicated for a total of 4 weeks. After that, functions of liver and kidney by AST, ALT, creatinine, BUN, DPPH and ABTS free radical scavenging activity, ROS (reactive oxygen species) production, NO (Total Nitric oxide), IL-$1{\beta}$, IL-6, TNF-${\alpha}$ production, weight changes in the hind legs of MIA-induced osteoarthritis rat, serum PGE2, TIMP-1, MMP-2, MMP-9, LTB4, hs-CRP, and white blood cells, neutrophils, lymphocytes, monocytes were measured. The volume of cartilage was observed by micro CT arthrography. H&E and Safranin-O staining were used to examine the injury of synovial tissue. Results 1. In the hind leg weight bearing measurement, level of weight was increased. 2. AST, ALT, BUN, creatinine were decreased. 3. The production of total white blood cell was decreased, and the production of neutrophils, lymphocytes, monocytes were significantly decreased. 4. The production of NO, PGE2, TIMP-1, MMP-2, MMP-9, LTB4 were significantly decreased, and the production of hs-CRP was also decreased but with no significance. 5. The cartilage volume was significantly increased. 6. In H&E staining and Safranin-O staning, the cartilage cell appeared to be proliferated, and proteoglycans appeared to be increased. Conclusions Based on the results above, Gamikyejakjimo-tang Herbal Acupuncture has anti-oxidation and anti-inflammation effects, which leads to suppressing the underlying causes and the progression of osteoarthritis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.1
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• pp.30-39
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• 2014

HanPoong Leading (HPL)-04 were prepared with different oriental medicines (balk of Kalopanax pictus balk, Chaenomelis Fructus, Angelica gigas root, Zingiber officinale, Raphanus sativus Linne and Saururus chinensis Baill.) to investigate the protective effects of HPL-04 on cartilage degradation in knee osteoarthritis (OA). Rat articular chondrocytes incubated with rhIL-$1{\alpha}$ markedly increased matrix metalloproteinase (MMP)-2 and 9 activities, decreased cell viability and reduced chondrogenic gene expression. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, MMP-2 and 9 activities and real time RT-PCR indicated that HPL-04 counteracted these harmful effects in dose-dependent manner. In addition, for experimental OA in vivo, monosodium iodoacetate (MIA, 0.5 mg/50 ${\mu}L$) was injected into knee joints of rats and administered HPL-04 to rats for 4 consecutive weeks after MIA treatment. The experimental data showed that treatment with HPL-04 significantly prevented of MMP-2 and 9 activities in articular cartilage. Histopathological and micro-CT evaluations of the knee joints also revealed that HPL-04 effectively ameliorated MIA-induced degenerative OA. In conclusion, HPL-04 has potential applicability for the prevention and treatment of degenerative OA.

• Journal of the Optical Society of Korea
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• v.20 no.5
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• pp.607-613
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• 2016

The pleura is known as an end target organ of exposure to toxic environmental materials such as fine particulate matter and asbestos. Moreover, long-term exposure to hazardous materials can eventually lead to fatal lung disease such as diffuse pleural fibrosis or mesothelioma. Chest computed tomography (CT) and ultrasound are gold standard imaging modalities for detection of advanced pleural disease. However, a diagnostic tool for early detection of pleural reaction has not been developed yet due to difficulties in imaging ultra-fine structure of the pleura. Optical coherence tomography (OCT), which provides cross-sectional images of micro tissue structures at a resolution of 2-10 μm, can image the mesothelium with a thickness of ~100 μm and therefore enables investigation of the early pleural reaction. In this study, we induced the early pleural reaction according to a time sequence after pleurodesis using talc, which has been widely used in the clinical field. The pleural reaction in talc grouped according to the time sequence (1st, 2nd, 4th weeks) showed a significant thickening (average thickness: 45 ± 7.5 μm, 80 ± 10.7 μm, 90 ± 12.5 μm), while the pleural reaction in sham and normal groups showed pleural change from normal to minimal thickening (average thickness: 16 ± 5.5 μm, 17 ± 4.5 μm, 15 ± 6.5 μm, and 12 ± 7.5 μm, 13 ± 2.5 μm, 12 ± 3.5 μm). The measurement of pleural reaction by pathologic examinations was well-matched with the measurement by OCT images. This is the first study for measuring the thickness of pleural reactions using a biophotonic modality such as OCT. Our results showed that OCT can be useful for evaluating the early pleural reaction.

• Restorative Dentistry and Endodontics
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• v.33 no.4
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• pp.323-331
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• 2008

Flexibility and fracture properties determine the performance of NiTi rotary instruments. The purpose of this study was to evaluate how geometrical differences between three NiTi instruments affect the deformation and stress distributions under bending and torsional conditions using finite element analysis. Three NiTi files (ProFile .06 / #30, F3 of ProTaper and ProTaper Universal) were scanned using a Micro-CT. The obtained structural geometries were meshed with linear, eight-noded hexahedral elements. The mechanical behavior (deformation and von Mises equivalent stress) of the three endodontic instruments were analyzed under four bending and rotational conditions using ABAQUS finite element analysis software. The nonlinear mechanical behavior of the NiTi was taken into account. The U-shaped cross sectional geometry of ProFile showed the highest flexibility of the three file models. The ProTaper, which has a convex triangular cross-section, was the most stiff file model. For the same deflection, the ProTaper required more force to reach the same deflection as the other models, and needed more torque than other models for the same amount of rotation. The highest von Mises stress value was found at the groove area in the cross-section of the ProTaper Universal. Under torsion, all files showed highest stresses at their groove area. The ProFile showed highest von Mises stress value under the same torsional moment while the ProTaper Universal showed the highest value under same rotational angle.