中炭素鋼의 疲勞强度의 定量的 評價

尹命辰 慶一大學校 1996 論文集 Vol.13 No.2

It is not clearly known how surface defects or inclusions of a medium carbon steel affect a fatique strength. In this study, we use SM35C specimens with spheroidized cementite structure to eliminate dependence of micro structure of fatigue crack. The investigation was carried out by crack closure, threshold condition and relation of defects size and fatigue limit. Experimenta findings are obtained as follows : (1) Fatigue crack initiation point of medium carbon steel with spheroidized cementite structure is surface defects. (2) Non-propagating crack length of smooth specimen and the critical size of defect is coincide. (3) In this case, fatigue limit of artificially defected specimen is lower than that of a flawless one, however, there exist allowance size of defect which don't get to influence at fatigue limit. (4) The critical length of the non-propagating crack of smooth specimen is the critical size of defect in transient area which decide threshold condition in steel with spheroidized cementite structure.

섬유소 밀봉제재를 이용한 백서의 두개골 임계결손의 치유

윤민호,구상환,박승하,RoyCOgle,이병일 대한성형외과학회 2003 Archives of Plastic Surgery Vol.30 No.1

This study was designed to evaluate the capacity of fibrin sealant to mediate the repair of critical size defects of rat calvaria. Twenty-four rats were randomized into four groups(n=6) and an 8-mm circular calvarial defect was made in each rat. In Group I and II, as control groups, defects were left untreated and evaluated at postoperative 6th and 12th week, respectively. In Group III and IV, defects were treated with fibrin sealant implantation and evaluated at the same point of time as in Group I and II, respectively. Results were examined by gross and histologic findings, simple radiographic study, and radiodensitometric analysis for bony density quantitatively. By gross and simple radiographic findings, animals with fibrin sealant implantation generally showed thick coverage of defects and focal radioopacity within defect area, but non-treated animals showed only fibrous healing. Histologically, small amount of new appositional bone growth was only seen at the edge of the defect at 6th week in Group III, but in Group IV, there are substantial amounts of new immature bone with well-organized patterns within the defect at 12th week postoperatively. In the radiodensitometric analysis, there was no statistically significant difference between Group I and Group III at 6th week. Compared with Group II, however, Group IV showed significant bony healing (p=0.0225) at 12th week. In conclusion, the fibrin sealant appeared to be an effective mediator in bone regeneration of this critical-sized calvarial defect model, but long-term implantation period should be needed for optimal results.

Investigation of a pre-clinical mandibular bone notch defect model in miniature pigs: clinical computed tomography, micro-computed tomography, and histological evaluation

Patricia L. Carlisle,Teja Guda,David T. Silliman,Wen Lien,Robert G. Hale,Pamela R. Brown Baer 대한구강악안면외과학회 2016 대한구강악안면외과학회지 Vol.42 No.1

Objectives: To validate a critical-size mandibular bone defect model in miniature pigs. Materials and Methods: Bilateral notch defects were produced in the mandible of dentally mature miniature pigs. The right mandibular defect remained untreated while the left defect received an autograft. Bone healing was evaluated by computed tomography (CT) at 4 and 16 weeks, and by micro-CT and non-decalcified histology at 16 weeks. Results: In both the untreated and autograft treated groups, mineralized tissue volume was reduced significantly at 4 weeks post-surgery, but was comparable to the pre-surgery levels after 16 weeks. After 16 weeks, CT analysis indicated that significantly greater bone was regenerated in the autograft treated defect than in the untreated defect (P=0.013). Regardless of the treatment, the cortical bone was superior to the defect remodeled over 16 weeks to compensate for the notch defect. Conclusion: The presence of considerable bone healing in both treated and untreated groups suggests that this model is inadequate as a critical-size defect. Despite healing and adaptation, the original bone geometry and quality of the pre-injured mandible was not obtained. On the other hand, this model is justified for evaluating accelerated healing and mitigating the bone remodeling response, which are both important considerations for dental implant restorations.

Circumferential bone grafting around an absorbable gelatin sponge core reduced the amount of grafted bone in the induced membrane technique for critical-size defects of long bones

Cho, J.W.,Kim, J.,Cho, W.T.,Kim, J.K.,Song, J.H.,Kim, H.J.,Masquelet, A.C.,Oh, J.K. J. Wright ; Butterworth-Heinemann ; Elsevier Scien 2017 Injury Vol.48 No.10

Objectives: The objectives of the study were to introduce a circumferential bone graft around an absorbable gelatin sponge core using an induced membrane technique, to assess its ability to reduce the required amount of graft and to maintain the bone graft, and to evaluate the clinical outcomes in the management of critical-size bone defects. Patients and methods: Circumferential bone grafting using a staged induced membrane technique for managing critical-size bone defects was performed in 21 patients. Postoperative computed tomography scans were performed 7days after Hemovac drain removal and 3 months after bone grafting. Volumetric measurements of the defect size, gelatin sponge proportion, and amount of grafted bone were performed by two independent observers using three-dimensional (3D) software. Results: The critical-size defects were located at the metadiaphyseal area of 11 tibias, eight femurs, and two humeri. The average defect size was 8.9cm in length and 65.2cm<SUP>3</SUP> in volume. The absorbable gelatin sponge core replaced 21.4% (average) of the defect volume. There was no significant deterioration in the shape of the grafted bone among the serial 3D models. Eighteen patients (86%) were healed radiographically at 9.1 months (average). Conclusion: Our study suggests that circumferential bone grafting in association with the induced membrane technique could reduce the required amount of bone graft and adequately maintain graft position and shape, with favourable clinical outcomes.

중탄소강의 피로크랙 개폐구의 특성 및 피로강도의 평가

윤명진 한국공작기계학회 1997 한국생산제조학회지 Vol.6 No.1

It is not clearly known how surface defects or inclusions of a medium carbon steel affect a fatigue strength. In this study, we used SM35C specimens with spheroidized cementite structure to eliminate dependence of miro structure of fatigue crack. The investigation was carried out by behavior of crack closure at non-propagating crack and effect of the fatigue limit according to the artificial defects size. Experimental findings are obtained as follows : (1) Fatigue crack initiation point of medium carbon steel with spheroidized cementite structure is at the surface defects. (2) Non-propagating crack length of smooth specimen is equal to the critical size of defect. (3) Considering the opening and closure behavior of fatigue crack, the defect shape results in various crack opening displacement, while it does not affects the fatigue limit level of medium carbon steel with spheroidized cementite structure. 4) The critical length of the non-propagating crack of smooth specimen is the same as critical size of defect in transient area which determines threshold condition in steel with spheroidized cementite structure.

Histomorphometric Study on Healing of Critical Sized Defect in Rat Calvaria using Three Different Bovine Grafts

( Khvan Ekaterina ),( Yemi Kim ),( Ji Youn Kim ),( Myung Rae Kim ),( Sung O Kim ),( Sun Jong Kim ) 한국조직공학·재생의학회 2012 조직공학과 재생의학 Vol.9 No.5

The objective of this study was to evaluate the feasibility of a new xenograft material Ti-Oss (Chiyewon, Guri, Korea) by investigating the degree of new bone formation compared with that of other commonly used xenografts Bio-Oss(R)(Geistlich Pharma AG, Wolhusen, Switzerland) and OCS-B(R)(NIBEC, Seoul, Korea). Forty rats were used in the study. The animals were randomly allocated into four groups of 10 animals each. The Group 1`s calvarial defect was untreated, Group 2`s defect was filled with Bio-Oss(R)(Geistlich Pharma AG), Group 3`s defect was filled with OCS-B(R)(NIBEC), and Group 4`s defect was filled with Ti-Oss(R)(Chiyewon). The animals were sacrificed at 2 (n=5) and 8 (n=5) weeks for histomorphometric analysis. The histomorphometric analysis showed the statistically significant difference between the groups with a mean bone formation of 0.35±0.10 mm (8.75%) for Bio-Oss(R) group, 0.19±0.04 mm (4.75%) for OCS-B(R) group, 0.26±0.04 mm (6.5%) for Ti-Oss(R) group at 2 week healing period. At 8 weeks, a mean bone formation of 1.93±0.18 mm (48.25%) for Bio-Oss(R) group, 1.12±0.11 mm (28%) for OCS-B(R) group, 1.50±0.28 mm (37.5%) for Ti-Oss(R) group showed the statistically significant difference (p < 0.05). Within the limits of present study, it was concluded that the newly investigated xenograft, Ti-Oss(R), revealed biocompatibility and effectiveness in bone formation. Ti-Oss(R) could be proposed as a potential material for filling osseous defects. Further clinical trials of the new bovine xenograft Ti-Oss(R) are needed for an understanding its relevance in dentistry.

교원질 제재(Zyderm^(�))가 백서의 두개골 결손 치유에 미치는 영향

이병일,정하영,동은상,한승규,구상환,박승하,김우경 大韓成形外科學會 2004 Archives of Plastic Surgery Vol.31 No.1

Effects of 4 Different Alloplastic Materials on Bone Regeneration in Rabbit Calvarial Defects

( Sun Jong Kim ),( Jin Won Lim ),( Jae Jun Ryu ),( Jin Soo Ahn ),( In Ho Han ),( Sang Wan Shin ) 한국조직공학·재생의학회 2009 조직공학과 재생의학 Vol.6 No.1

The purpose of this study was to compare bone regeneration in 8-mm defects in 8 New Zealand White rabbit calvaria using 4 different alloplastic bone substitutes. Four 8-mm calvarial defects were made in the parietal bone of each animal. The defects were filled with Bongros-HA™(Bioalpha, Seongnam, Korea), micro macroporous biphasic calcium phosphate(MBCP™, Biomatlante, France), Osteon™(Dentium Co, Seoul, Korea) and Cerasorb (R)(Curasan, Kleinsthei, Germany). Two animals died after surgery. Two rabbits were sacrificed after 4 weeks, and the other 4 were sacrificed after 8 weeks. Data analysis included the qualitative assessment of the calvarial specimens. Histomorphometric analysis was performed to quantify the amount of new bone within the defects. It was found that Osteon™-treated defects had significantly more new bone after 8 weeks thanall other groups. Osteon™ was an effective alloplastic bone substitute which showed reliable osseous healing of critical size defects in the rabbit calvarium. From the results of this study, it is suggested that TCP-coated HA may induce a better bone regeneration ability than either HA or TCP or both.

Bone Healing Properties of Autoclaved Autogenous Bone Grafts Incorporating Recombinant Human Bone Morphogenetic Protein-2 and Comparison of Two Delivery Systems in a Segmental Rabbit Radius Defect

Choi, Eun Joo,Kang, Sang-Hoon,Kwon, Hyun-Jin,Cho, Sung-Won,Kim, Hyung Jun Korean Association of Maxillofacial Plastic and Re 2014 Maxillofacial Plastic Reconstructive Surgery Vol.36 No.3

Purpose: This study aims to validate the effect of autoclaved autogenous bone (AAB), incorporating Escherichia coli-derived recombinant human bone morphogenetic protein-2 (ErhBMP-2), on critical-sized, segmental radius defects in rabbits. Delivery systems using absorbable collagen sponge (ACS) and fibrin glue (FG) were also evaluated. Methods: Radius defects were made in 12 New Zealand white rabbits. After autoclaving, the resected bone was reinserted and fixed. The animals were classified into three groups: only AAB reinserted (group 1, control), and AAB and ErhBMP-2 inserted using an ACS (group 2) or FG (group 3) as a carrier. Animals were sacrificed six or 12 weeks after surgery. Specimens were evaluated using radiology and histology. Results: Micro-computed tomography images showed the best bony union in group 2 at six and 12 weeks after operation. Quantitative analysis showed all indices except trabecular thickness were the highest in group 2 and the lowest in group 1 at twelve weeks. Histologic results showed the greatest bony union between AAB and radial bone at twelve weeks, indicating the highest degree of engraftment. Conclusion: ErhBMP-2 increases bony healing when applied on AAB graft sites. In addition, the ACS was reconfirmed as a useful delivery system for ErhBMP-2.

우골에서 추출한 골형성단백을 이용한 백서 두개골 결손부 치유에 관한 연구

채윤필(Yun Pil Chae),이종호(Jong Ho Lee),김수경(Soo Kyung Kim),여환호(Hwan Ho Yeo) 대한구강악안면외과학회 1997 대한구강악안면외과학회지 Vol.23 No.2

Bovine BMP had been partially purified by guanidine HCI extraction and heparin affinity chromatography. It had distinct 3 bands between 20kDa and 30kDa in SDS-polyacrylamide gel electrophoresis. The critical size defect of rat calvaria, 8mm size in diameter, was used to establish osteoinductive activity of BMP and other bone graft materials. Bovine BMP plus IBM(inactivated bone matrix) as a carrier, allogenic demineralized freeze-dried bone (DFDB) and autogenous cortico-cancellous bone were implanted into the 12 rat skull defect of each group in order to evaluate repairing capacity The animals were sacrificed at the week of 2nd, 4th, 6th and 8th after operation The results were as follows 1. In the BMP-IBM complex Implantation group, the defect has been repaired completely by the 8th postoperative week. At 2 week, duster of chondroblast and cartilage appeared around the BMP-coated implant matrix. Calcification began at 6 week. At 8 week, the woven bone changed lamella bone with hematopoietic marrow and it has been bridged the both end of skull defect. 2. The repairing speed and quantity of new bone formation of BMP-IBM complex implant were superior to those of autogenous bone graft and DFDB implant. The defect which was filled with DFDB healed not only by new bone but also by retained implanted bone. The inflammatory and immune reaction of DFDB graft were more apparent than those of BMP implant and autogenous bone graft. 3. It has been assumed that the bovine BMP could be effectively used for the treatment of complicated bone defects in oral and maxillofacial region.