• The Journal of Advanced Prosthodontics
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• v.10 no.3
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• pp.167-176
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• 2018

PURPOSE. The purpose of this study was to compare the new bone formation capability of zirconia with those of other synthetic bone grafts. MATERIALS AND METHODS. Twelve rabbits were used and four 6-mm diameter transcortical defects were formed on each calvaria. Each defect was filled with Osteon II (Os), Tigran PTG (Ti), and zirconia (Zi) bone grafts. For the control group, the defects were left unfilled. The rabbits were sacrificed at 2, 4, and 8 weeks. Specimens were analyzed through micro computed tomography (CT) and histomorphometric analysis. RESULTS. The Ti and Zi groups showed significant differences in the amount of newly formed bone between 2 and 4 weeks and between 2 and 8 weeks (P<.05). The measurements of total bone using micro CT showed significant differences between the Os and Ti groups and between the Os and Zi groups at 2 and 8 weeks (P<.05). Comparing by week in each group, the Ti group showed a significant difference between 4 and 8 weeks. Histomorphometric analysis also showed significant differences in new bone formation between the control group and the experimental groups at 2, 4, and 8 weeks (P<.05). In the comparison of newly formed bone, significant differences were observed between 2 and 4 weeks and between 2 and 8 weeks (P<.05) in all groups. CONCLUSION. Zirconia bone graft material showed satisfactory results in new bone formation and zirconia could be used as a new synthetic bone graft material.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.3
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• pp.221-226
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• 2007

Purpose The purpose of this study is to evaluation of effect on bone formation of PRP and fibrin sealant with deproteinized bovine bone(Bio-Oss) grafts on rabbit cranial defect. Material and Methods Twelve rabbits were used as experimental animal Two equal 9mm diameter cranial bone defects were created in each rabbit and immediately grafted with Bio-Oss only, Bio-Oss and PRP, and Bio-Oss and Fibrin sealant. Rabbits were sacrificed at 4 and 8 week. The defects were evaluated by histomorphometric analysis. Results Kruskal-Wallis tests were performed comparing new bone formation via histomorphometric analysis. No statistically significant difference of new bone formation was found between Bio-Oss only, Bio-Oss and PRP, and Bio-Oss and fibrin sealant at 4 and 8 weeks (P>0.05). Conclusion This study fails to find a stimulatory effect of PRP and Fibrin sealant on New bone formation of Bio-Oss grafts by histomorphometric analyses.

• Journal of Periodontal and Implant Science
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• v.29 no.3
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• pp.507-519
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• 1999

The ultimate objective of periodontal treatment is to stop disease progression and to regenerate destroyed periodontal tissues and thereby regain normal function. Growth factors are naturally found polypetides which stimulate many cellular activities pertaining to wound healing by acting as signal molecule in controlling cell movement, proliferation, and matrix production. Platelet derived growth factor (PDGF) is 28,000-35,000 Da molecular weight dimeric protein with 2 long positively charged polypeptide chains connected by sulfide bonds. The purpose of this study is to evaluate histologically the initial guided tissue regeneration in a periodontal defect f a beagle dog treated with a biodegradable membrane formed with polylactic acid (poly-L-lactic acid) and polyglycolic acid loaded with 200ng/$cm^2$ platelet derived growth factor. 2 beagle dogs were used in he experiment. $5mm{\times}6mm$ alveolar bone defect was formed in upper and lower canines and third premolars and a reference notch was placed. PDGF-BB non-containing membrane was used as control. Each defect was randomly assigned to the test roup or the control group. The dogs were sacrificed 3 weeks after membrane placement. Toluidine blue and multiple staining was done for histological analysis. In the 3 week specimen in the control group, no new one formation could be seen. Small amount f bone resorption below the notch could be seen. In the notch, loose connective tissue with infiltration of inflammatory cells could be seen. Also thin discontinuous new cementum could be seen and the membrane still retained its structure. Where PDGF-BB containing membrane was used, new bone formation could be seen in the notch at weeks and also continuous thin cementum could be seen. PDL cells were observed between new bone and new cementum and some were attached to bone and cementum. These results suggest that new bone and cementum formation seen when PDGF-BB loaded membrane was used was due to inhibition of downgrowth of epithelial cells and also due to continuous release of the growth factor. Further study on the resorption characteristics of the membrane nd the release characteristics of the PDGF-BB is necessary. Also, development of a membrane easier to use clinically is necessary.

• Journal of Periodontal and Implant Science
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• v.37 no.3
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• pp.497-509
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• 2007

Bone morphogenetic proteins(BMPs) are regarded as members of the transforming growth $factor-{\beta}$ superfamily with characteristic features in their amino acid sequences. A number of studies have demonstrated the biologic activities of BMPs, which include the induction of cartilage and bone formation. Recently there was a attempt to overcome a limitation of mass production, and economical efficieny of rh-BMPs. The method producing PTD by using bacteria have advantages of acquiry a mass of proteins. Hences, a new treatment which deliver protein employed by protein transduction domain(PTD) has been tried. The purpose of this study was to evaluate the bone regenerative effect of TATBMP-2 and TAT-HA2-BMP-2 employed by PTD from HlV-1 TAT protein for protein translocation in the rat calvarial model. An 8mm calvarial, critical size osteotomy defect was created in each of 32 male Spraque-Dawley rats(weight $250{\sim}300g$). The animals were divided into 4 groups of 32 animals each (4 animals/group/healing interval). The defect was treated with TATBMP-2/ACS(Absorbable collagen sponge) (TATBMP-2 0.1mg/ml), TAT-HA2-BMP-2/ACS(TAT-HA2-BMP-2 0.1mg/ml), ACS alone or left untreated for surgical control(negative control). The rats were sacrificed at 2 or 8 weeks postsurgery, and the results were evaluated histologically. The results were as follows: New bone formation were not significantly greater in the TATBMP-2/ACS group relative to negative, and positive control groups. New bone was evident at the defect sites in TAT-HA2-BMP-2/ACS group relative to negative, positive control and TATBMP-2 groups. There were a little bone regeneration in TATBMP-2 groups. While, enhanced local bone formation were observed in TAT-HA2-BMP-2 group. But, The results was not the same in all rat defects. Therefore, further investigations are required to develop a method. which disperse homogenously, and adhere to target cells.

• Journal of Korea Foundry Society
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• v.41 no.3
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• pp.241-251
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• 2021

7000-series aluminum alloys are noted for their superior strength compared with other Al alloys, and their billets are generally fabricated by direct-chill (DC) casting. Surface defects in a DC-cast aluminum billet are mainly related to exudation and the meniscus freezing phenomenon, which are influenced by alloy compositions, casting speed, and casting temperature. 7000-series aluminum alloys have a wide freezing range during solidification, which makes it easy for casting defects to occur. In this study, we investigated surface defect evolution in casting billets of Al-8Zn-2Mg-2Cu alloy fabricated by a DC casting process. The billets showed "wavy" or "dotted" surfaces. The wavy surface was formed by meniscus freezing at a lower casting speed (200 mm/min) and temperature (655 ℃). In the wavy surface, refined dendritic cells were observed in a concave region due to the constitutional supercooling caused by meniscus freezing. Meanwhile, at a higher casting temperature (675 ℃), the dotted surface was formed by pore formation. In the dotted surfaces in the billet formed at a high casting speed (230 mm/min), an exudation layer was formed by the high metallostatic head pressure. The dotted region and the smooth region had a refined dendritic morphology and a columnar morphology at the exudation layer, respectively. This is attributed to the formation of gas pores in the dotted region.

• Journal of Periodontal and Implant Science
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• v.54 no.2
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• pp.96-107
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• 2024

Purpose: Deproteinized bovine bone or synthetic hydroxyapatite are 2 prevalent bone grafting materials used in the clinical treatment of peri-implant bone defects. However, the differences in bone formation among these materials remain unclear. This study evaluated osteogenesis kinetics in peri-implant defects using 2 types of deproteinized bovine bone (Bio-Oss^® and Bio-Oss/Collagen^®) and 2 types of synthetic hydroxyapatite (Apaceram-AX^® and Refit^®). We considered factors including newly generated bone volume; bone, osteoid, and material occupancy; and bone-to-implant contact. Methods: A beagle model with a mandibular defect was created by extracting the bilateral mandibular third and fourth premolars. Simultaneously, an implant was inserted into the defect, and the space between the implant and the surrounding bone walls was filled with Bio-Oss, Bio-Oss/Collagen, Apaceram-AX, Refit, or autologous bone. Micro-computed tomography and histological analyses were conducted at 3 and 6 months postoperatively (Refit and autologous bone were not included at the 6-month time point due to their rapid absorption). Results: All materials demonstrated excellent biocompatibility and osteoconductivity. At 3 months, Bio-Oss and Apaceram-AX exhibited significantly greater volumes of formation than the other materials, with Bio-Oss having a marginally higher amount. However, this outcome was reversed at 6 months, with no significant difference between the 2 materials at either time point. Apaceram-AX displayed notably slower bioresorption and the largest quantity of residual material at both time points. In contrast, Refit had significantly greater bioresorption, with complete resorption and rapid maturation involving cortical bone formation at the crest at 3 months, Refit demonstrated the highest mineralized tissue and osteoid occupancy after 3 months, albeit without statistical significance. Conclusions: Overall, the materials demonstrated varying post-implantation behaviors in vivo. Thus, in a clinical setting, both the properties of these materials and the specific conditions of the defects needing reinforcement should be considered to identify the most suitable material.

• Archives of Plastic Surgery
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• v.33 no.6
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• pp.748-752
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• 2006

Purpose:Circular skin lesions between 10 and 35 mm in diameter generate problems often. Direct closure of the lesion risks excessive wound tension or wound dehiscence. Skin grafts heal slowly and often remain unsightly. Traditional skin flaps have a limited role. We treated this circular medium-sized skin lesion(10 - 35 mm sized) by reducing opposed multilobed(ROM) flap. Methods: ROM flap involves a series of semicircular lobes extending both cephalic and caudal from the defect. Direction of the semicircular multilobed flap is set parallel to relaxed skin tension line(RSTL) to minimize scar formation. First semicircle is drawn 60% in diameter of the defect. Second semicircles are drawn at the cephalic and caudal aspects of the original semicircles. These semicircles are 60% in diameter of the first semicircle. Additional semicircles are repeatedly drawn until the tension of skin flaps becomes free. ROM flap has a length-to-base ratio of 0.5 resulting in lower theoretical risk of end flap necrosis than a random pattern flap with a large ratio. The technique involves lobes most distant from the primary defect being transposed in turn closer to the defect. Results: The ROM flap reduces skin tension concerns, lowers the risk of flap necrosis and allows for quicker and more aesthetic healing. Results were generally good and major complications, such as dehiscence, infection, or delayed healing, did not occur. Conclusion: ROM flap repair allows the plastic surgeon an additional option when faced with a circular medium-sized skin lesion.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.4
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• pp.325-336
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• 2000

Bone morphogenetic protein-2/4 are members of Transforming Growth Factor-$\beta$(TGF-$\beta$) superfamily and they may induce formation of cartilage and bone in vivo. This study was performed to investigate the cellular target and period of action of BMP-2/4 and understanding of actions of BMP-2/4 at cellular level. The appearance of BMP-2/4 during healing of mandibular and periodontal defect in rat was evaluated immunohistochemically. 40 Sprague-Dawley strain white male rats, each weighing about 300gm were used. Bony defect was performed in the mandible and they were sacrificed at the day of 3rd, 10th, 20th, 30th after operation. The specimens were harvested and examined histologically and immunohistochemically by localization of anti-BMP-2/4. The results were as follows: 1. Woven bone was observed at 10th day and perfect healing of defect with compact bone and periodontal ligment space at 30th day. 2. Osteoprogenitor cells, osteoblastic cells and periosteum were positive reaction to immunohistochemical stain at 10th day. 3. Cells of bone marrow space and surface cells of osteocytes and cementoblasts were positive reaction to immunohistochemical stain at 20th day. 4. Newly formed osteocytes and cementocytes were positive reaction to immunohistochemical stain at 30th day. From the above findings, we could conclude that BMP-2/4 acted significant roles as factors of induction, proliferation and differentiation during bone healing process.

• Archives of Craniofacial Surgery
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• v.19 no.1
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• pp.35-40
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• 2018

Background: When a skin defect occurs, clinicians must work to restore the original skin quality as soon as possible. Accordingly, an artificial dermis can be used to supplement the wound and prevent severe scar contracture formation. The Terudermis is an artificial dermis that is simple and easy to use. We investigated the effectiveness of the Terudermis in the treatment of facial skin defects by analyzing previous relevant cases treated in our institution. Methods: We retrospectively examined 143 patients who were treated with the Terudermis graft in facial skin defect at Dong Kang General Hospital in 2015 and 2016. The patients' age, sex and location, wound size, complications were analyzed. In addition, the patients were asked to complete a self-satisfaction questionnaire after 18 months from the completion of treatment. The results were compared with that of autologous full-thickness skin graft (FTSG) and split-thickness skin graft (STSG) patients in same period. Results: The mean self-satisfaction scores evaluated by patients were $4.1{\pm}1.0$, $4.0{\pm}1.3$ and $3.5{\pm}1.8$ for the Terudermis graft, FTSG and STSG patients, respectively. With respect to complications, there were fewer incidences of hematoma, partial skin loss and complete skin loss in the Terudermis graft patients. Conclusion: In the present study, the Terudermis, when used to treat post-traumatic facial skin defects, is a good alternative option to obtain satisfactory aesthetic outcomes. Also, the Terudermis grafting is a simple and easy treatment method to perform.

• Journal of Periodontal and Implant Science
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• v.40 no.4
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• pp.172-179
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• 2010

Purpose: Accurate and exact measurement is an important factor for generating meaningful results in any properly designed study. If all the participating examiners are able to yield similar results, it will be possible to evaluate the objective results of the study more easily and quickly. The purpose of this study was to evaluate the intra- and inter-examiner reproducibility of histometric measurements in the intrabony periodontal defect model. Methods: One wall intrabony defects were surgically created at the distal aspect of the second and the medial aspect of the fourth mandibular premolars in the right and left jaw quadrants in twenty beagle dogs and the defect sites received the following ${\beta}$-tri calcium phosphate, growth differentiation factor-0, growth differentiation factor-100 and sham surgery. Histometric analysis was performed after 8 weeks. Histometric parameters were recorded and repeated at three months interval by three examiners. Intra- and inter-examiner reproducibility was assessed. Results: Most parameters of all the groups showed high intra- and inter-examiner reproducibility. Parameters including defect height, bone regeneration height, cementum regeneration height, and formation of junctional epithelium yielded interexaminer correlation ${\geq}0.9$. The intra-examiner reproducibility showed a high result, over 0.9. Conclusions: Histometric evaluation of the one-wall intra-alveolar periodontal defect model showed high reproducibility not only for a single given examiner but also among the three examiners.