• The Journal of Korean Academy of Prosthodontics
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• v.34 no.4
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• pp.722-745
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• 1996

The purpose of this study is to investigate the effect of constant direct current electrical stimulation in healing the bone defects and surrounding tissues of the endo-oseous(TPS-IMZ) implants. Implants were inserted in the femur of adult dogs. Then a constrant direct current of approximately $10{\mu}A$ was applied. Artificial bone defects were prepared on one side of the implant site. Experimental groups were divided into 4 : control group : bone defect without treatment group I : bone defect filled with hydroxyapatite powders group II : bone defect, in which a negative and positive electrodes were inserted 5mm apart from both sides of the implant group III : bone defect, in which negative current was directly connected to the IMZ implant and a positive electrode was placed 10mm apart from the implant The animals were sacrificed in the 1st, 2nd, 4th and 8th week after implantation for the light microscopic examination. The results obtained were as follows : 1. In electrically stimulated experimental groups, new bone formation and osseointegration around implants were accelerated. 2. Group III showed the greatest activity in new bone formation. Osteoconductivity around HA particles was observed in group 1. 3. The defect area of the control group was healed by forming new bone, which grew from the underlying cancellous bone. The defect areas of the electrically stimulated experimental groups were healed by newly formed bone, which grew upward from the cancellous bone and downward from the periosteum. 4. 8 weeks after implantation, all the groups showed good osseointegration between the surrounding bone and implants.

• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.179-190
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• 2008

Purpose: In this study, the effect of micro-macroporous biphasic calcium phosphate(MBCP) incorporated with inorganic polyphosphate for bone regeneration in the calvaria of rabbit was evaluated. Materials and Methods: The procedure of guided bone regeneration was performed with titanium reinforced expanded polytetrafluoroethylene(TR-ePTFE) membrane. Four animal groups were compared : 1) TR-ePTFE membrane for negative control group, 2) TR-ePTFE membrane filled with MBCP for positive control group, 3) TR-ePTFE membrane filled with MBCP soaked in 4% inorganic polyphosphate for experimental group I, and 4) TR-ePTFE membrane filled with MBCP soaked in 8% inorganic polyphosphate for experimental group II. Results: 1. Negative control group showed the highest new bone formation at 16 weeks. 2. Positive control group showed the smallest new bone formation compared to other groups. 3. 8% inorganic polyphosphate induced more volume of bone formation, otherwise experimental group II did not show significant difference compared to negative control group. Conclusion: These results suggest that inorganic polyphosphate has a promoting effect on bone regeneration, possibly by enhancing osteoconductivity of the carrier and by increasing osteoinductivity of the defected alveolar bone tissue.

• Journal of Periodontal and Implant Science
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• v.39 no.1
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• pp.95-102
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• 2009

Purpose: The aim of this report is to investigate the efficacy of anorganic bovine bone xenograft(Bio-$Oss^{(R)}$) at maxillary sinus floor augmentation. Materials and methods: Two male patients who missed maxillary posterior teeth were included. They were performed maxillary sinus floor augmentation using anorganic bovine bone xenograft(Bio-$Oss^{(R)}$). After 10 or 13 months, the regenerated tissues were harvested using trephine drills with 2 or 4mm diameter and non-decalcified specimens were made. The specimens were examined histologically and histomorphometrically to investigate graft resorption and new bone formation. Results: Newly formed bone was in contact with Bio-$Oss^{(R)}$ particles directly without any gap between the bone and the particles. The proportions of newly formed bone were $23.4{\sim}25.3%$ in patient 1(Pt.1) and 28.8% in patient 2(Pt.2). And the proportions of remained Bio-$Oss^{(R)}$ were $29.7{\sim}30.2%$ in Pt.1 and 29.2% in Pt.2. The fixtures installed at augmented area showed good stability and the augmented bone height was maintained well. Conclusion: Anorganic bovine bone xenograft(Bio-$Oss^{(R)}$) has high osteoconductivity and helps new bone formation, so that it can be used in maxillary sinus floor augmentation.

• Journal of Veterinary Clinics
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• v.40 no.2
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• pp.85-92
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• 2023

Fractures in the horse industry are challenging and a common cause of death in racehorses. To accelerate fracture healing, tissue engineering (TE) provides promising ways to regenerate bone tissues. This study aimed to evaluate the osteogenic effects of biphasic calcium phosphate collagen (BCPC) graft, bone morphogenetic protein 2 (BMP2), mesenchymal stem cell (MSC), and platelet-rich plasma (PRP) treatments in horses. Four thoroughbred horses were included in the study, and, in each horse, three cortical defects with a diameter of 5 mm and depth of 10 mm were formed in the third metacarpal bones (MC) and metatarsal bones (MT). The defects were randomly assigned to one of six treatment groups (saline, BCPC, BMP2, MSC, PRP, and control). Injections of saline, BMP2, PRP, or MSCs were made at 1, 3, and 5 weeks after defect surgery. Bone regeneration effects were assessed by radiography, quantitative computed tomography (QCT), micro-computed tomography (μCT), histopathological, and histomorphometric evaluation. The new bone ratio (%) in the histomorphometric evaluation was higher in the BMP2 group than in the control and saline groups. Radiographic and QCT values were significantly higher in the BCPC groups than in the other groups. QCT values of the BMP2 group were significantly higher than in the control and saline groups. The present study demonstrated that BCPC grafts were biologically safe and showed osteoconductivity in horses and the repeated injections of BMP2 without a carrier can be simple and promising TE factors for treating horses with bone fractures.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.6
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• pp.491-497
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• 2001

Polymethylmethacrylate(PMMA) is currently commonly used material for the reconstruction of bone defects and fixation of joint prosthetics following congenital and acquired causes. Although PMMA has widespread use, it does not possess the ideal mechanical characteristics with osteoconductivity and osteoinductivity required. In order to overcome these problem, addition of bovine bone drived defatting demineralized bone(BDB) powders to a PMMA bone cement was done for improvement of physical property and bone forming characteristics of composite. In order to investigate the influence of BDB reinforcement on the PMMA, we measured physical property of compressive, tensile, flexural strength, and scanning electron microscopic examinations. The results were obtained as follows: 1. The PMMA forms a solid cellular matrix with open cells about $100{\mu}m$ in variable size and incorporating BDB. BDB aggregates inside the cells form a porous network that is accessible from the outer surface. 2. The physical properties were compressive strength of mean $22.74{\pm}1.69MPa$, tensile strength of mean $22.74{\pm}1.69MPa$, flexural strength of mean $77.53{\pm}6.93MPa$. Scanning electron microscopic examinations were revealed that there was DBD particles form a highly porous agglomerates. BDB can be added PMMA in the form of dried powders, the composites are applicable as bone substitutes. BDB and PMMA mixture is shown to produce a class of composites that due to their microstructure and improved mechanical properties may be suitable for application as bone subsitutes. The mechanical and material properties of the BDB-PMMA bone substitute composites are competitive with those properties of a porous ceramic matrix of other hydroxyapatite and with those of natural bones.

• Journal of the Korean Ceramic Society
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• v.45 no.10
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• pp.618-624
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• 2008

Various calcium phosphate bioceramics are distinguished by their excellent biocompatibility and osteoconductivity. Especially, the exceptional biodegradability of $\beta$-TCP makes it a bone graft substitute of choice in many clinical applications. The activation of osteoclasts, differentiated from macrophage precursor cells, trigger a cell-mediated resorption mechanism that renders $\beta$-TCP biodegradable. Based on this evidence, we studied the biodegradation process of granular-type $\beta$-TCP bone graft substitute through in vitro and in vivo studies. Raw 264.7 cells treated with RANKL and M-CSF differentiated into osteoclasts with macrophage-like properties, as observed with TRAP stain. These osteoclasts were cultured with $\beta$-TCP nano powders synthesized by microwave-assisted process. We confirmed the phagocytosis of osteoclasts by observing $\beta$-TCP particles in their phagosomes via electron microscopy. No damage to the osteoclasts during phagocytosis was observed, nor did the $\beta$-TCP powders show any sign of cytotoxicity. We also observed the histological changes in subcutaneous tissues of rats implanted with granule-type $\beta$-TCP synthesized by fibrous monolithic process. The $\beta$-TCP bone graft substitute was well surrounded with fibrous tissue, and 4 months after implantation, 60% of its mass had been biodegraded. Also, histological findings via H&E stain showed a higher level of infiltration of lymphocytes as well as macrophages around the granule-type $\beta$-TCP. From the results, we have concluded that macrophages play an important role in the biodegradation process of $\beta$-TCP bone graft substitutes.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.3
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• pp.311-316
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• 2008

Calcium phosphate cement (CPC) has been used as bone substitute successfully due to good biocompatibility and osteoconductivity. One of the important mechanical characteristics of CPC is flowablility, which can be evaluated by measuring rheological parameters. However, there have been few studies that measured rheological properties of CPC. The purpose of this study was to evaluate the rheological properties of CPC paste mixed with 2 kinds of setting solutions, 2% hydroxyprophyl methylcellulose (HPMC) and 35% polyacrylic acid (PAA). The CPC used was dicalcium phosphate dihydrate (DCPD). Rheological properties of CPC paste were measured using rheometer. The statistical analysis was carried out with Mann-whitney test with Bonferronis collection. CPC with both setting solutions showed shear thinning behavior. CPC with 2% HPMC showed signigicantly higher complex viscosity than CPC with 35% PAA(p<0.05).

• Journal of Korean Foot and Ankle Society
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• v.14 no.1
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• pp.58-65
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• 2010

Purpose: This study was performed to evaluate the clinical outcomes of operative treatment using porous hydroxyapatite for intraarticular calcaneal fracture of joint depression type. Materials and Methods: Twenty patients with intraarticular calcaneal fracture were followed up for more than 1 year. The period to union was calculated to evaluate the osteoconductivity of porous hydroxyapatite used as bone graft substitute. The measurement of Bohler angle, Gissane angle and the degree of articular surface depression was performed through preoperative and postoperative radiographs. The clinical evaluation was performed according to hindfoot score of the American Orthopaedic Foot and Ankle Society (AOFAS) and scale of the Creighton-Nebraska health foundation (CNHF). Results: Bohler angle and Gissane angle had improved significantly from preoperative average $10.4^{\circ}$, $117.8^{\circ}$ to average $22.6^{\circ}$, $113.5^{\circ}$ immediate postoperatively, and had maintained to average $21.2^{\circ}$ and $114.4^{\circ}$ at the last follow-up. The degree of articular surface depression had improved significantly from preoperative average 4.8 mm to 1.5 mm at the last follow-up. All cases achieved bone union, and the interval to union was average 12.8 weeks. AOFAS score was average 85.2 points at last follow-up. There were 7 excellent, 10 good, and 3 fair results according to the CNHF scale. Therefore, 17 cases (85%) achieved satisfactory results. Conclusion: Plate fixation using porous hydroxyapatite seems to be one of effective treatment methods for intraarticular calcaneal fracture of joint depression type, because of supporting the reduction of subtalar articulation by augmenting bony defect and facilitating bone formation. Further evaluation about long-term radiological changes and histological analysis on hydroxyapatite implantation site should be required.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.4
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• pp.371-377
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• 2014

In tissue engineering, a scaffold is a three-dimensional(3D) structure that serves as a template for regeneration the functions of damaged tissues or organs. Among materials for scaffolds, polycaprolactone(PCL) and ${\beta}$-tricalcium phosphate(${\beta}$-TCP) are biodegradable and biocompatible. In this study, we fabricated 3D PCL, blended PCL (60 wt %)/${\beta}$-TCP (40 wt %), and pure ${\beta}$-TCP scaffolds by a multi-head scaffold fabrication system. Scaffolds with a pore size of $600{\pm}20{\mu}m$ was observed by scanning electron microscopy. The effects of 3D PCL, blended PCL (60 wt %)/${\beta}$-TCP (40 wt %) and pure ${\beta}$-TCP scaffolds were analyzed by evaluating their mechanical characteristics. In addition, in an in-vitro study using osteoblast-like saos-2 cells, we confirmed the effects of 3D scaffolds on cellular behaviors such as cell adhesion and proliferation. In summary, the 3D blended PCL (60 wt %)/${\beta}$-TCP (40 wt %) scaffold was found to be suitable for human cancellous bone in terms of its the compressive strength, biocompatibility, and osteoconductivity. Thus, blending PCL and ${\beta}$-TCP could be a promising approach for fabricating 3D scaffolds for effective bone regeneration.

• Journal of Periodontal and Implant Science
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• v.37 no.4
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• pp.871-879
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• 2007

Purpose: The purpose of this study was to evaluate the bone regeneration of novel biodegradable amorphous calcium phosphate. Materials and Method: An 8-mm, calvarial, critical-size osteotomy defect was created in each of 20 male Sprague-Dawley rats(weight $250{\sim}300g$). The animals were divided into two groups of 10 animals each and allowed to heal for 2 weeks(10 rats). The first group was the control group and the other group was the experimental group which received the novel biodegradable calcium phosphate. Results: The healing of the calvarium in the control group was uneventful. The histologic results showed little bone formation in the control group. The experimental group which received the novel biodegradable calcium phosphate showed a normal wound healing. There were a lot of new bone formation around the biomaterial in 2 weeks. The bone formation increased in 8 weeks when compared to 2 weeks and there was a significant bone increase as well(P<0.01). The nobel biodegradable calcium phosphate showed statistical significance when compared to the control group (P<0.05). The novel biodegradable calcium phosphate in 8 weeks showed a significant increase in bone formation when compared to 2 weeks $(40.4{\pm}1.6)$(%). The biodegradable calcium phosphate which is made from mixing calcium phosphate glass(CPG), NaCO and NaOH solution, is biocompatible, osteoconductive and has a high potency of bone formation. Conclusion: We can conclude that the novel biodegradable calcium phosphate can be used as an efficient bone graft material for its biodegradability and osteoconductivity.