• 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 the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.4
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• pp.282-291
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• 2004

Pure-phase beta-tricalcium phosphate(${\beta}$-TCP) proved to be a bone regeneration material, providing the patient with vital bone at the defect site in a reasonable time, making a second surgical procedure for bone harvesting unnecessary. This study compares bone healing and BMP 2/4 expression in cranial defects in rabbits grafted with autogenous bone and ${\beta}$-TCP. Thirty New Zealand White rabbits was divided into 3 group of 10 animals each. Bilateral calvarial defects were made in the parietal bones of each animal. ${\beta}$-TCP placed in one defect and the other defects was filled with autogenous bone. The animal were sacrificed at 4, 8 and 12 weeks. Immunohistochemical analysis was used to investigate the expression of BMP 2/4. 1. The new bone formation around autogenous bone from 4 weeks and ${\beta}$-TCP from 8 weeks. 2. In autogenous bone graft, BMP 2/4 expression was decreased from 4 to 12 weeks. 3. In ${\beta}$-TCP graft, BMP 4 expression was increased from 8 to 12 weeks. But, BMP 2 was observed from 12 weeks. This study showed that bone healing, regeneration and, BMP 2/4 expression are delayed in grafted ${\beta}$-TCP than autogenous bone.

• Journal of Periodontal and Implant Science
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• v.40 no.4
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• pp.180-187
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• 2010

Purpose: This study evaluated the spontaneous healing capacity of surgically produced cranial defects in rabbits with different healing periods in order to determine the critical size defect (CSD) of the rabbit cranium. Methods: Thirty-two New Zealand white rabbits were used in this study. Defects of three sizes (6, 8, and 11 mm) were created in each of 16 randomly selected rabbits, and 15-mm defects were created individually in another 16 rabbits. The defects were analyzed using radiography, histologic analysis, and histometric analysis after the animal was sacrificed at 2, 4, 8, or 12 weeks postoperatively. Four samples were analyzed for each size of defect and each healing period. Results: The radiographic findings indicated that defect filling gradually increased over time and that smaller defects were covered with a greater amount of radiopaque substance. Bony islands were observed at 8 weeks at the center of the defect in both histologic sections and radiographs. Histometrical values show that it was impossible to determine the precise CSD of the rabbit cranium. However, the innate healing capacity that originates from the defect margin was found to be constant regardless of the defect size. Conclusions: The results obtained for the spontaneous healing capacity of rabbit cranial defects over time and the underlying factors may provide useful guidelines for the development of a rabbit cranial model for in vivo investigations of new bone materials.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.5
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• pp.417-433
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• 2006

Purpose : Platelet rich plasma (PRP) is an autologous material with many growth factors, such as BMPs, PDGF, $TGF-{\beta}_1$, $TGF-{\beta}_2$, VEGF, and IGF, facilitating bone healing process. The prominent osteoconductive activity and the biodegradable nature of beta-tricalciumphosphate (${\beta}-TCP$) for bone grafts in animal experiments have been reported. The purpose of this study was to evaluate the effect of PRP on the osteogenesis of ${\beta}-TCP$. Materials & Methods : Two artificial calvarial bone defects were made in 32 rabbits which were divided into 2 groups. In one group of 16 rabbits, autogenous bone / ${\beta}-TCP$ was grafted on each side of cranial bone defect. In the other group of 16 rabbits, mixture of ${\beta}-TCP$ and PRP / PRP alone was grafted on each side of the cranial bone defect. The animals were sacrificed at 2, 4, 8, and 12 weeks after surgery. The specimens were harvested and examined histologically and immunohistochemically by the expression of BMP2/4/7, PDGF, VEGF and $TGF-{\beta}_1$. Results : The mean volume of new bone formation was significantly higher at 4, 8, 12 weeks in autogenous graft than that in ${\beta}-TCP$. The BMP2/4 expression was significantly higher at 4 weeks in autogenous bone graft and at 4 weeks in mixture of ${\beta}-TCP$ and PRP and at 12 weeks in ${\beta}-TCP$. The expression of BMP7, PDGF, VEGF and $TGF-{\beta}_1$ showed no significant difference in autogenous, ${\beta}-TCP$, mixture of ${\beta}-TCP$ and PRP, and PRP alone during grafted bone regeneration. Conclusion : The results showed that PRP had no additional value in promoting healing process of ${\beta}-TCP$ grafts.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.38
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• pp.27.1-27.9
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• 2016

Background: The objective of this study was to place bone graft materials in cranial defects in a rabbit model and compare their bone regenerating ability according to the size and density of demineralized dentin matrix (DDM). Methods: We selected nine healthy male rabbits that were raised under the same conditions and that weighed about 3 kg. Two circular defects 8 mm in diameter were created in each side of the cranium. The defects were grafted with DDM using four different particle sizes and densities: 0.1 mL of 0.25- to 1.0-mm particles (group 1); 0. 2 mL of 0.25- to 1.0-mm particles (group 2); 0.1 mL of 1.0- to 2.0-mm particles (group 3); and 0.2 mL of 1.0- to 2. 0-mm particles (group 4). After 2, 4, and 8 weeks, the rabbits were sacrificed, and bone samples were evaluated by means of histologic, histomorphometric, and quantitative RT-PCR analysis. Results: In group 1, osteoblast activity and bone formation were greater than in the other three groups on histological examination. In groups 2, 3, and 4, dense connective tissue was seen around original bone even after 8 weeks. Histomorphometric analysis of representative sections in group 1 showed a higher rate of new bone formation, but the difference from the other groups was not statistically significant. RT-PCR analysis indicated a correlation between bone formation and protein (osteonectin and osteopontin) expression. Conclusions: DDM with a space between particles of $200{\mu}m$ was effective in bone formation, suggesting that materials with a small particle size could reasonably be used for bone grafting.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.1
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• pp.49-58
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• 2008

Objective: The Purpose of the study was to investigate the bone morphogenic protein expression of rhBMP-2(recombinant human bone morphogenic protein-2) as singnaling molecule and ${\beta}-TCP$(Tricalcium phosphate) as a bone substitute and carrier medium of rhBMP-2. Materials and Methods: 16 rabbits divided into 2 group of each 8 rabbit. Two standardized bone defect, round bilateral defect was made in the cranium of the 8 rabbit of first group, and was grafted with $150{\sim}500{\mu}m$ diameter ${\beta}-TCP$ 0.25g in one side, which was soaked with rhBMP-2, and autogenous bone was grafted on another side as a positive control. Second group of 8 rabbit, only ${\beta}-TCP$ was grafted with same size and same manner. After 2, 4, 8, and 12 weeks, specimen was taken for microscopic immunohiostochemical and histomorphometric analysis. Result: Grafting ${\beta}-TCP$ with rhBMP show the early formation of the bone regenerative factor (BMP-4) and more quantity of new bone formation than only use of ${\beta}-TCP$ (8,12 week), even show less new bone formation than autogenous bone. Conclusion : The experimental study result that ${\beta}-TCP$ graft combination with rhBMP-2 as a delivery system is an effective with osteoinductive capacity and biodegradable properties, so that provide clinical availibility of composite use in reconstruction of bony defect.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.4
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• pp.264-273
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• 2002

Pulsed electromagnetic field (PEMF) was used first to induce osteogenesis in 1974. The appliance which was consisted of the Helmholtz coil configuration have used to osteogensis. The objective of this study was to determine whether PEMF, a frequency of 100 Hz and magnetic field strength of 38 gauss applied to the calvarial defect in rabbit, could affect the induction of osteogenesis and the healing of the graft bone. This field should not produce excitation of nerve or muscle and heating the tissue. To evaluate the effect of PEMF on osteogenesis, 16 rabbit under the same condition was divided into 8 experimental groups and 8 control groups. 10 mm calvarial bone defects were formed around sagittal suture. The defect of left side was left without graft while the defect of right side was grafted by bone harvested from left side. A pulsed electromagnetic field was applied for 8 hours per day. Each group was sacrificed after 1 week, 2 weeks, 4 weeks, 8 weeks. Microscopic specimens were obtained from the calvarial bone defects and surrounding tissue using Hematoxylin-Eosin staining method. The results were as follows. 1. In the group which pulsed electromagnetic field was applied, new bone formation filled up the defect was observed after 4 and 8 weeks effectively. 2. There are no difference in the healing period for the fusion between the bone and graft bone. According to the result, the PEMF with 38 Gauss, 100 Hz was very effective in the healing of bone defect and new bone formation. So The PEMF will be useful in clinical aspect for oseteogenesis.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.1
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• pp.164-174
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• 1996

In order to develop the allogeneic bone implants instead of autogenous bone grafts for maxillofacial reconstruction, undemineralized freeze-dried human bone was processed. The freeze-dried human bone was implanted into the cranial and mandibular defects of the rabbits. The implants were evaluated clinically, roentgenographically and histomophometrically. And immunohistochemical evaluation of the implants was performed on the rat. The results were as follows : 1. When compared with control defects of $0.8{\times}0.8\;cm$, the implants on the rabbit defects displayed complete osseous bridging clinically and roentgenographically. Histomophometrically a minimal inflammatory cell infiltrate was present but the defects healed well clinically. 2. When compared with control grafts, the freeze-dried implants on the rat muscle displayed decreased antigenicity by immunohistochemical evaluation, due to freeze-drying process. 3. Undemineralized freeze-dried human bone in this study can be preserved as a bank bone in this study and seems to be applicable for clinical allogeneic bone grafts.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.4
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• pp.428-434
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• 2008

Introduction: Piezosurgery device is one of the most commonly used instrument on the intraoral surgery such as maxillary sinus lift and autogeneous bone graft. Piezosurgery instrument also contains the tips that are manufactured especially for the convenient bone graft, which now many surgeons apply them for collecting bone graft materials in the curettage method for the restoration of skull defects. However, objective data has not been shown concerning the effects about bone graft with using Piezosurgery. Therefore we investigated the effects of Piezosurgery on the rabbit-skull defect healing. Materials & Methods: To investigate the regeneration of the bony defect with various bone graft, 10 adult New Zealand white rabbits (average weight : $2.8{\pm}0.3kg$, about 12weeks) were used. The four circular bony defects measuring 6mm in diameter were made with Piezosurgery device on each rabbit cranial bone. The harvested bone tissues during defect formation were also used for autogeneous bone graft. They were grafted into the defects in a various type; block type (Group 1), particulated type by the bone mill (Group 2), chopped type by curette shaped Piezosurgery tip (Group 3), the defect without any graft was served as control (control group). The animals were sacrificed after 6 weeks and bone regeneration capacity was evaluated histomorphometrically. Result & Conclusion: Autogeneous bone graft harvested using a Piezosurgery instrument showed satisfactory bone regeneration. There was no conspicuous difference bone prepared among by bone mill or Piezosurgery and block bone graft. Therefore, the bone harvested from the intraoral site near the operation field using the piezosurgery device can be a feasible and reliable graft for intraoral bony defects.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.4
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• pp.360-373
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• 2006

The purpose of this research was to investigate whether pulsed electromagnetic field (PEMF) stimulation applied to the rabbit cranial defects grafted with ${\beta}$-tricalcium phosphate (${\beta}$-TCP) could affect the new bone formation. With 16 New Zealand white rabbits under the same condition, bilateral calvarial bone defects were formed around the sagittal suture line. The defect on the left side was grafted with ${\beta}$-TCP, while on the right side was grafted by harvested autogenous bone. PEMF was applied to 8 rabbits for 8 hours per day. The bony specimen were divided into 3 groups, the group 1 was autogenous bone grafted specimen, the group 2 was ${\beta}$-TCP grafted with PEMF, and the group 3 was ${\beta}$-TCP grafted without PEMF. We investigated the bone regeneration & growth factor expression at 2, 4, 6, and 8 weeks. As a result, BMP 2 was expressed in the group 1 from 2 weeks, the group 2 from 4 weeks, and the group 3 from 6 weeks. BMP 4 was expressed in the group 1 from 2 weeks, in the group 2 and the group 3 from 4 weeks. 4. There was no significant difference in expression pattern of BMP 7, PDGF, VEGF, and TGF-${\beta}$1 during grafted bone regeneration in group 1, 2, and 3. According to our results, PEMF stimulation could be effective on the new bome formation in animal study, and have a feasibility of clinical use.