• 한국표면공학회지
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• 제29권2호
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• pp.81-92
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• 1996

The cementless fixation of bone ingrowth by porous coatings on artificial hip joint prostheses are replacing polymethylmethacrylate(PMMA) bone cement fixations. However, the major interests in the field of porous metal coating are environmental corrosivity accelerated by metal ion release, deterioration in the mechanical property of the coating, and the mechanical failure of the coatings as well as the substrate. Therefore, the selection of right materials for coatings and the development of porous coating techniques must be accomplished. Because of the existing problems in Ti and Ti alloys which are used extensively, this study is focused on the plasma spraying technique for coating on super stainless steel substrate. In order to determine the optimum conditions which satisfy the requirement for the porous coatings, under the plasma spraying, we selected the experimental parameters which extensively influenced on the characteristics of the coating through the pre-examination. Spray distance has been selected among 120, 160, and 200mm and primary gas flow rate among 70, 100, and 130 SCFH. Current and secondary gas($H_2$) flow rate was fixed at 400A, and 15 SCFH respectively. To understand the characteristics of the coatings, surface morphology, cross-sectional micro-structure, surface roughness, residual stress, and corrosion resistance were elucidated and the best conditions for the bone ingrowth improvement on artificial hip joint prostheses were found.

• 치과방사선
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• 제13권1호
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• pp.151-162
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• 1983

The author analyzed the morphologic changes of bone structure from 848 radiograph is (424 joints) of 212 patients with temporomandibular joint arthrosis, which were obtained by the oblque-Iateral transcranial projection and orthopantomography. The interelation of the bone changes and condylar head positions the results were as follows: 1. In the 212 patients with TMJ arthrosis, 210 patients(99.05%) show the condylar positional changes. Among them, 187 patients 989.05%) show the bone changes. 2. In TMJ arthrosis patients with bone changes, 10% patients(57.75%) show both the condylar positional changes and bone changes. 66 patients( %) show the condylar psoitional changes bilaterally and bone changes unilaterally. On the other hand, 11 patients (5.88%) show the condylar positional changes unilaterally and bone change bilaterally. 3. The bone changes in the TMJ arthrosis patients with the condylar positional changes were as follows: There were the flatlening of articular surface in 103 cases (26.55%) the erosion in 99cases 925.57%), and the erosion in 88 cases (22.68%). There were not much differences among the three types of bone changes. And the deformity in 70 cases (18.04%), the sclerosis in 22 cases(5.67%), the marginal protiferation in 6 cases(1.55%) were seen. 4. The regions of bone changes in TMJ arthrosis patients with condylar positional changes were as follows: They occurred at the condyle head(51.04%), the articular eminence(39.20%) and the articular fossa(9.60%) in that order. The condylar positional changes and bone changes according to the regions were as follows: a) In the bone changes at the condyle head, the flatteming (34.63%) was a most frequent finding and the deformity(27.63%) the erosion(24.32%) in the order. In the condylar positional changes, the downward positioning of condyle(41.44%) was a most frequent finding in the mouth closed state and the restricted movement within the articular fossa(35.46%) in the mouth open state. b) In the bone changes at the articular eminence, the eburnation(33.26%) was a most frequent finding and the flatteming(31.16%), the erosion(28.37%) in that order. In the condylar positional changes, the downward positionirg of condyle(39.81%) was a most frequent finding in the mouth closed state and the restricted movement within the articular fossa(24.77%) in the mouth open state. c) In the bone changes at the articular fossa, the eburnation(72.90%) was amost frequent finding and theerosion(17.76%), the sclerosis(9.35%) in that arder. In the condylar positional changes, the downward positionirg of condyle(41.5%) was a most frequent finding in the mouth closed state and the mormal positionirg of condyle(27.78%) in the mouth open state.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제18권3호
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• pp.515-527
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• 1996

The most serious problem resulting from estrogen deficiency induce osteo porosis. Recently, they make efforts to inquire a relation between hematopoietic organ and bone loss due to estrogen deficiency. Estrogen have an effect on growth and formation of skeletal system, and inhibit bone resorption under the influence of osteoblast and osteoclast, and basically inhibit the increase of hematopoietic progenitor and immune factor connected with bone resorption and prevent the osteoid formation. The purpose of this article was to observe the change of spleen and effect on hematopoietic function following estrogen administration. In this study, female rats of 150g weight was ovariectomized, after 70 days, experimental group was injected estrogen at interval of a week and sacrificed on 1, 2, 3, 4, 6 weeks. Control group was sacrificed after ovariectomy on 11, 12, 13, 14, 16 weeks without estrogen injection, and normal rats were sacrificed for harvest of spleen and femur. Paraffin sections and H&E stain was performed, and observed under light microscope. The obtained results were as follows. 1. From 11 to 12 weeks at bone marrow of control group, hematopoietic cells were decreased in comparison with normal group, and lipid infiltration was seen, and irregular bone remodelling was seen after 13 weeks. From 14 to 16 weeks, there were more decreased hematopoietic cells and lipid degeneration, and lipid degeneration of hematopoietic cells appeared. 2. All the bone marrow of experimental group, the structure of hematopoietic cells with decreased lipid infiltration was recovered from 2 weeks of estrogen adminstration and maintained to 6 weeks. 3. At spleen of control group, borders of white and red pulp was not well demarcated, and size of white pulp was decreased. 4. At spleen of experimental group, borders between white and red pulp have been well demarcated from 3 weeks of estrogen adminstration relatively, and white pulp was increased with distinct border. From above findings, we could regarded that estrogen deficiency due to ovariectomy influenced on hematopoietic cells of bone marrow and spleen, and histologic recovery of hematopoietic cells were observed after 3 weeks of estrogen adminstration even if it was not reach to normal group.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1994년도 추계학술대회
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• pp.71-74
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• 1994

In cementless total hip arthroplasty(THA), an initial stability of the femoral component is mandatory to achieve bony ingrowth and secondary long term fixation. Bone ingrowth depends strongly on relative micromotion and stress distributions at the interface. Primary stability of the femoral component can be obtained by minimizing the magnitude of relative micromotions at bone-prosthesis interface, Hence an accurate evaluation of interface behavior and stress/strain fields in the bone implant system may be relevant for better understanding of clinical situations and improving THA design. However, complete evaluation of load transfer in the bone remains difficult to assess experimentally, Hence, recently finite element method (FEM) was introduced in orthopaedic research field to fill the gap due to its unique capacity to evaluate stress in structure of complex shape, loading and material behavior. The authors developed the 3-dimensional numerical finite element model which is composed of totally 1179 elements off and 8 node blick. We also analyzed the micromotions at the bone-stem interface and mechanical behavior of existing bone prosthesis for a loading condition simulating the single leg stance. The result indicates that the values of relative motion for this well fit Multilock stem were $150{\mu}m$ in maximum, $82{\mu}m$ in minimum, and the largest relative motion developed in medial region of proximal femur with anterior-posterior direction. The proximal region of the bone was much larger in motion than the distal region and the stress pattern shows high stress concentration on the cortex near the tip of the stem. These findings indicates that the loading in the proximal femoral bone in the early postoperative situation can produce micromotions on the interface and clinically cementless TEA patient should not be allowed weight bearing strictly early in the postoperative period.

• Archives of Plastic Surgery
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• 제38권1호
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• pp.96-101
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• 2011

Purpose: In treatment of facial bone fracture, occurred in children, we generally use wires, miniplate, absorbable plate or their combination. These foreign bodies can be palpable, and sometimes may cause infections, and need reoperation for removing. When bone fragments are multiple, small or thin, they are hard to handle and make accurate reduction of all fragments. In these cases, a biodegradable tissue adhesive, Histoacryl$^{(R)}$ (n-butyl-2-cyanoacrylate), can be used as fixation technique for small, multiple, and thin fracture fragments. Methods: 3 years old and 6 years old children, who has comminuted fracture on frontal sinus, we used Histoacryl$^{(R)}$ for fixation of multiple bone fragments. After approaching by coronal incision, we pulled out all bone fragments and reconstructed bone fragments by Histoacryl$^{(R)}$ and fixed those on frontal sinus by absorbable plates. Results: Photographs and 3-dimensional CT obtained preoperatively and postoperatively. And we compared them each other in terms of accuracy of reconstructed bony contour. We could reconstruct almost all bone fragments easily along 3-dimensional structure and get excellent aesthetic results. There was no complication such as infection. Conclusion: In treatment of comminuted facial bone fracture, occurred in children, Histoacryl$^{(R)}$ is an excellent method for accurate reconstruction in small and thin bone fragments which cannot be fixed by wire, miniplate or absorbable plate without complication.

• Imaging Science in Dentistry
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• 제43권4호
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• pp.227-233
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• 2013

Purpose: This study was performed to analyze human maxillary and mandibular trabecular bone using the data acquired from micro-computed tomography (micro-CT), and to characterize the site-specific microstructures of trabeculae. Materials and Methods: Sixty-nine cylindrical bone specimens were prepared from the mandible and maxilla. They were divided into 5 groups by region: the anterior maxilla, posterior maxilla, anterior mandible, posterior mandible, and mandibular condyle. After the specimens were scanned using a micro-CT system, three-dimensional microstructural parameters such as the percent bone volume, bone specific surface, trabecular thickness, trabecular separation, trabecular number, structure model index, and degrees of anisotropy were analyzed. Results: Among the regions other than the condylar area, the anterior mandibular region showed the highest trabecular thickness and the lowest value for the bone specific surface. On the other hand, the posterior maxilla region showed the lowest trabecular thickness and the highest value for the bone specific surface. The degree of anisotropy was lowest at the anterior mandible. The condyle showed thinner trabeculae with a more anisotropic arrangement than the other mandibular regions. Conclusion: There were microstructural differences between the regions of the maxilla and mandible. These results suggested that different mechanisms of external force might exist at each site.

• 치과방사선
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• 제11권1호
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• pp.79-87
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• 1981

The author analysed the interrelation between the morphologic changes of bone Structures and the position of condylar head from the routine radiographs of 134 cases of the temporomandibular joint arthrosis. The frequencies of coincidence between the site of bone defrmity and condylar head positional change were examined. Also, the positional changes of condylar head and the direction of condylar movement in relation to the kind of bone deformities were observed. The results obtained were as follows; 1. In 52.65 per cent of total cases, the site, of positional change of condylar head was coincided with the site of bone deformans. The frequencies of the coincidence between these in the five items among seven items examined were above 53 per cent. From the results, it seems that the positional changes of condylar head were related with the morphological change of bone structure. 2. Eburnation and erosion. revealed frequently positional changes in the opening and closing position of the mouth, although in the early stages of the TMJ arthrosis. 3. In the bone deformans, during opene position of the mough 44.81 per cent of total cases revealed backword movement and 37.74 per cent showed forward movement. In closed position of the mouth, downward movement was revealed in 35.23 per cent of total cases and upward movement 28.41 per ,cent of total cases. 4. In the cases showing eburnation, the frequencies of coincidence between the site of positional change and bone deformans were 58.57 per cent of the total cases. that means it was high in the early stages of the TMJ arthrosis.

• Journal of Ginseng Research
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• 제37권4호
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• pp.435-441
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• 2013

This study investigated the effects of Korean Red Ginseng (KRG) on radiation-induced bone loss in C3H/HeN mice. C3H/HeN mice were divided into sham and irradiation (3 Gy, gamma-ray) groups. The irradiated mice were treated for 12 wk with vehicle, KRG (per os, p.o.) or KRG (intraperitoneal). Serum alkaline phosphatase (ALP), tartrate-resistant acid phosphatase, estradiol level, and biomechanical properties were measured. Tibiae were analyzed using micro-computed tomography. Treatment of KRG (p.o., 250 mg/kg of body weight/d) significantly preserved trabecular bone volume, trabecular number, structure model index, and bone mineral density of proximal tibia metaphysic, but did not alter the uterus weight of the mice. Serum ALP level was slightly reduced by KRG treatment. However, grip strength, mechanical property, and cortical bone architecture did not differ among the experimental groups. The results indicate that KRG can prevent radiation-induced bone loss in mice.

• Imaging Science in Dentistry
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• 제52권2호
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• pp.171-179
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• 2022

Purpose: The aim of this study was to assess the accuracy of cone-beam computed tomographic (CBCT) images obtained using different voxel sizes in measuring trabecular bone microstructure in comparison to micro-CT. Materials and Methods: Twelve human skull bones containing posterior-mandibular alveolar bone regions were analyzed. CBCT images were obtained at voxel sizes of 0.075mm(high: HI) and 0.2mm(standard: Std), while microCT imaging used voxel sizes of 0.06 mm (HI) and 0.12 mm (Std). Analyses were performed using CTAn software with the standardized automatic global threshold method. Intraclass correlation coefficients were used to evaluate the consistency and agreement of paired measurements for bone volume (BV), percent bone volume (BV/TV), bone surface (BS), trabecular thickness (TbTh), trabecular separation (TbSp), trabecular number (TbN), trabecular pattern factor(TbPf), and structure model index (SMI). Results: When compared to micro-CT, CBCT images had higher BV, BV/TV, and TbTh values, while micro-CT images had lower BS, TbSp, TbN, TbPf, and SMI values (P<0.05). The BV, BV/BT, TbTh, and TbSp variables were higher with Std voxels, whereas the BS, TbPf, and SMI variables were higher with HI voxels for both imaging methods. For each imaging modality and voxel size evaluated, BV, BS, and TbTh were significantly different(P<0.05). TbN, TbPf, and SMI showed statistically significant differences between imaging methods(P<0.05). The consistency and absolute agreement between micro-CT and CBCT were excellent for all variables. Conclusion: This study demonstrated the potential of high-resolution CBCT imaging for quantitative bone morphometry assessment.

• 한국임상수의학회지
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• 제2권1호
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• pp.155-159
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• 1985

The lesions of maxillary swelling observed during necropsy of a korean native pony aged 5 years old were consistent with osteodystrophia fibrosa microscopically. The maxillary lesion was characterized by completely altered bone structure showing complex processes of marked bone resorption with extensive fibrous replacement and accelerated osteoid formation.