• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.1
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• pp.87-94
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• 2001

The present study was performed to investigate the effect of $HTR^{(R)}$ (Hard Tissue Replacement) on osteogenesis in the mandibular bone defects. Eight adult male white rabbits weighing 2.5 to 3.0kg were used. Four bone defects (8mm in diameter and 4mm in depth) were made at the both mandibular body. In the control group, the right mesial bone defect was filled with blood clot and spontaneously healed. In the DFDB group, the right distal bone defect was filled with xenogenic demineralized freeze-dried bone. In the $HTR^{(R)}$ group, the left mesial bone defect was filled with $HTR^{(R)}$. In the $HTR^{(R)}-membrane$ group, the left distal bone defect was filled with $HTR^{(R)}$ and covered with BioMesh membrane. The rabbits were sacrified at 2,4,6 and 9 weeks after the operation and microscopic examination was performed. Results obtained were as follows: In the control and DFDB groups, inflammatory cells and the fibrous connective tissue existed and the bone growth was slower than $HTR^{(R)}$ group by 6 week, and there was intervention of the soft tissue at 9 week. In the $HTR^{(R)}$ group, bone trabeculi extended between the $HTR^{(R)}$ particles without intervention of inflammatory cells and the connective tissue at 4 and 6 weeks. In addition, extensive osseous ingrowth into the $HTR^{(R)}$ particles was observed at 9 week. Bone formation was more active in the $HTR^{(R)}$ group than the control and DFDB groups. There was not obvious difference in the bone healing rate between the $HTR^{(R)}$ and the $HTR^{(R)}-membrane$ group. These results suggest that the $HTR^{(R)}$ promotes osteogenesis in the bone defects and the $HTR^{(R)}$ group has no difference in comparison with the $HTR^{(R)}-BioMesh^{(R)}$ membrane group in bone healing.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.6
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• pp.557-564
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• 2000

The bone graft materials can be grossly divided into autogenous bone, allogenic bone, xenogenic bone, and alloplastic material. Much care was given to other bone graft materials away from autogenous bone due to its additional operation for harvesting, delayed resorption and limitation of quantity. Demineralized freeze-dried bone(DFDB) and hydroxyapatite are the representatives of bone graft materials. As resorbable hydroxyapatite is developed in these days, the disadvantage of nonresorbability can be overcome. So we planned to study on the strength and the bone formation at the rats calvarial defects of DFDB graft and those of the composite graft with DFDB and resorbable hydroxyapatite. We used the 16 male rats weighting range from 250 to 300 gram bred under the same environment during same period. After we made the 6mm diameter calvarial defect, we filled the DFDB in 8 rats and DFDB and resorbable hydroxyapatite in another 8 rats. We sacrificed them at the postoperative 1 month and 2 months with the periostium observed. As soon as the specimens were delivered, we measured the compressive forces to break the normal calvarial area and the newly formed bone in calvarial defect area using Instron(Model Autograph $S-2000^{(R)}$, Shimadzu, Japan). The rest of the specimens were stained with H&E(Hematoxylin & Eosin) and evaluated with the light microscope. So we got the following results. 1. In every rats, there was no significant difference between the measured forces of normal bone area and those of the bone graft area. 2. In 1 month, the measured forces at DFDB graft group were higher than those of the DFDB and resorbable hydroxyapatite composite graft group(P<0.05). 3. In 2 months, there was no significant differences between the measured forces of DFDB graft group and those of the DFDB and resorbable hydroxyapatite composite graft group. 4. In lightmicroscopic examination, most of the grafted DFDB were transformed into bone in 1 month and a large numbers of hydroxyapatite crystal were observed in DFDB and resorbable hydroxyapatite composite graft group in 1 month. 5. Both group showed no inflammatory reaction in 1 month. And hydroxyapatite crystals had a tight junction without soft tissue invagination when consolidated with newly formed bone. 6. In both groups, newly formed bone showed the partial bone remodeling and the lamellar bone structures and some of reversal lines were observed in 2 months. From the above results, it is suggested that DFDB and resorbable hydroxyapatite composite graft group had a better resistance to compressive force in early stage than DFDB graft group, but there would be no significant difference between two groups after some period. And it is suggested that the early stage of bone formation procedure of DFDB and resorbable hydroxyapatite composite graft group was slight slower than that of DFDB graft group, but there would be no significant difference between two groups after some period.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.5
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• pp.406-414
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• 2011

Thermally induced bone necrosis during implant surgery is a rare phenomenon and a potential contributing factor to implant failure. The frictional heat generated at the time of surgery causes a certain degree of necrosis of the surrounding differentiated and undifferentiated cells. The bone necrosis occurred in the mandible in all three cases, leading to a soft tissue lesion and pain. In each case, radiolucent areas appeared in the middle and apical portions of the implant 4 weeks after surgery. Thermally induced bone necrosis did not improve following systemic antibiotic medication, necessitating surgical treatment. The nonintegrated implants were removed, and meticulous debridement of dead bone and granulation tissue was performed. Then, new implants were implanted along with the placement of autogenous and xenogenic bone covered with a collagen membrane. No further complications occurred after re-operation. The radiolucencies around the new implants gradually resolved entirely, and the soft tissue lesions healed successfully. At 4-5 months after reoperation, implant loading was initiated and the implant-supported restorations have been functioning. The aim of this case report is to present the successful clinical treatment of three cases suspected to be caused by thermally induced bone necrosis after implant drilling.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.6
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• pp.391-397
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• 2012

Purpose: The purpose of this study was to evaluate the effectiveness of the platelet-rich fibrin (PRF) used in combination with the porcine cancellous bone as a scaffold, in promoting bone regeneration in the bone defects ofthe rabbit calvaria. Methods: Ten rabbits were used in the study. Three round-shaped defects (diameter 8.0 mm) were created in the rabbit calvaria and were filled with nothing (control group), porcine cancellousbone (Experimental Group 1, porcine bone) and PRF-mixed porcine cancellous bone (Experimental Group 2). TS-GBB is a xenogenic bone-substitute product comprised of a high heat-treated mineralized porcine cancellous bone. Animals were sacrificed at 6 weeks and 12 weeks for the histological and radiographic evaluations. Results: In the micro computed tomography and histological results, the experimental groups 1 and 2 showed more bone formation, remodeling, and calcification than the control group. The new bone formation ratio showed theGroup 2 to be larger than Group 1 at6 and 12 weeks. However, there was no significant difference between the experimental groups 1 and 2 in the new bone formation area, at the 6 and 12 weeks (P>0.05). Conclusion: The PRF-mixed group showed more bone formation than the porcine cancellousbonegroup (TS-GBB), butthere was a no significant difference. The PRF may not lead to enhanced bone healing when grafted with the porcine cancellous bone.

• Archives of Plastic Surgery
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• v.37 no.4
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• pp.323-328
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• 2010

Purpose: Adipose-derived stromal cells (ADSCs) are multipotent cells that have been found to promote wound healing through the process of angiogenesis and reepithelialization. Generally, it is well known that the antigenicity of ADSCs doesn't affect stem cell therapy. In this study, we investigated the effect of allogeneic ADSCs in the wound healing process by applying allogeneic ADSCs on the wound healing splint model of mice. Methods: Adipose tissue was harvested from the epididymal fat pads of BALB/c and C57BL/6 mice. Twenty four mice BALB/c were divided into three groups; control, isogeneic, and allogeneic groups. Two full thickness defects with 6 mm diameters were created on the back of BALB/c mice. $1{\times}10^6$ ADSCs from BALB/c mice were applied on the isogeneic group. In the allogeneic group, ADSCs from the C57BL/6 mice were applied. No cells were applied to the control group. The sizes of the wounds were evaluated in 3, 5, 7, 10, and 14 days after the wounds were applied, and tissues were harvested in 7 and 14 days for histological analysis. Results: Wound healing rates had showed significant increase in 10, and 14 days when the isogeneic group was compared to the control group, but the allogeneic group showed significantly decrease compared to the isogeneic group (p<0.05). Histological scores in the isogeneic group were significantly high, but significantly lower in the allogeneic group when compared to the isogeneic group in 2 weeks (p<0.05). In the isogeneic group, thick inflammatory cell infiltration with abundant capillaries were observed in 1 week, and thick epithelium with many large capillaries were observed in 2 weeks. Conclusion: When isogeneic ADSCs were applied to wounds, they presented a faster wound healing rate compared to controls and the allogeneic group. Unlike general stem cell therapy, these findings suggest that cell therapy targeted at enhancing wound healing may benefit from the use of ADSCs with identical antigenicity, as opposed to allogeneic or xenogenic ADSCs.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.576-587
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• 2010

Background: Effective decellularization and fixation process is critical, in order to use xenogenic valves clinically. In the present study, we decellularized bovine pericardium using sodium dodecyl sulfate (SDS) and N-lauroyl sarcosinate, treated with $\alpha$-galactosidase, and then fixed in various manners, to find out the most effective tissue preservation & fixation procedure. Material and Method: Bovine pericardium was decellularized with SDS and N-lauroyl sarcosinate, and treated with $\alpha$-galactosidase. Both groups were fixed differently, by varying glutaraldehyde (GA) or EDC (1-ethyl-3-(3-dimethyl aminopropyl)-carbodiimide)/N-hydroxysuccinamide (NHS) treatment conditions. Thereafter, physical examination, tensile strength test, thermal stability test, cytotoxicity test, pronase test, pronase-ninhydrin test, purpald test, permeability test, compliance test, H&E staining, DNA quantification, and $\alpha$-galactose staining were carried out to each groups. Result: GA fixed groups showed better physical properties and thermal stability than EDC/NHS fixed groups, EDC/NHS-GA dual fixed groups showed better physical properties and thermal stability than EDC/NHS fixed groups, and showed better thermal stability than GA fixed groups. In pronase test and pronase-ninhydrin test, GA fixed groups and EDC/NHS-GA dual fixed groups showed stronger crosslinks than EDC/NHS groups. Permeability and compliance tended to increase in EDC/NHS-GA dual fixed groups, compared to GA fixed groups. But, EDC/NHS-GA dual fixed groups had stronger tensile strength and lower cytotoxicity than GA fixed groups. Conclusion: We have verified that EDC/NHS-GA dual fixation can make effective crosslinks and lower the toxicity of GA fixation. Henceforth, we will verify if EDC/NHS-GA dual fixation can lower calcifications & tissue failure in vivo experiment.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.3
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• pp.243-248
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• 2009

Purpose: Rehabilitation of the edentulous posterior maxilla with dental implants often poses difficulty because of insufficient bone volume caused by pneumatization of the maxillary sinus and by crestal bone resorption. Sinus grafting technique was developed to increase the vertical height to overcome this problem. The present study was designed to evaluate the sinus floor augmentation with anorganic bovine bone (Bio-$cera^{TM}$) using histomorphometric and clinical measures. Patients and methods: Thirteen patients were involved in this study and underwent total 14 sinus lift procedures. Residual bone height was ${\geq}2mm$ and ${\leq}6mm$. Lateral window approach was used, with grafting using Bio-$cera^{TM}$ only(n=1) or mixed with autogenous bone from ramus and/or maxillary tuberosity(n=13). After 6 months of healing, implant sites were created with 3mm diameter trephine and biopsies taken for histomorphometric analysis. The parameters assessed were area fraction of new bone, graft material and connective tissue. Immediate and 6 months after grafting surgery, and 6 months after implantation, computed tomography (CT) was taken and the sinus graft was evaluated morphometric analysis. After implant installation at the grafted area, the clinical outcome was checked. Results: Histomorphometry was done in ten patients.Bio-$cera^{TM}$ particles were surrounded by newly formed bone. The graft particles and newly formed bone were surrounded by connective tissue including small capillaries in some fields. Imaging processing revealed $24.86{\pm}7.59%$ of new bone, $38.20{\pm}13.19%$ connective tissue, and $36.92{\pm}14.51%$ of remaining Bio-$cera^{TM}$ particles. All grafted sites received an implant, and in all cases sufficient bone height was achieved to install implants. The increase in ridge height was about $15.9{\pm}1.8mm$ immediately after operation (from 13mm to 19mm). After 6 months operation, ridge height was reduced about $11.5{\pm}13.5%$. After implant installation, average marginal bone loss after 6 months was $0.3{\pm}0.15mm$. Conclusion: Bio-$cera^{TM}$ showed new bone formation similar with Bio-$Oss^{(R)}$ histomorphometrically and appeared to be an effective bone substitute in maxillary sinus augmentation procedure with the residual bone height from 2 to 6mm.