• The Korean Journal of Ceramics
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• v.6 no.3
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• pp.214-218
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• 2000

Hydroxyapatite (HA) and $\beta$-tricalcium phosphate ($\beta$-TCP) are bio-compatible materials with bones and teeth. HA has been widely applied as bone substitutes because of chemical stability in vivo, while $\beta$-TCP has higher resorbability than HA when the material is implanted in a bone defect. In the present study, both HA and $\beta$-TCP porous ceramics were soaked in the simulated body fluid in order to investigate the reaction between the materials and the fluid. After the soaking test, carbonate hydroxyapatite was formed on HA surface at 1 week, and then the amount of precipitates increased with increasing period of the soaking test. While $\beta$-TCP was not dissolved in the fluid, carbonate hydroxyaopatite was also formed on $\beta$-TCP surface after 12 weeks, and the amount of precipitates was less than that on HA. In vitro behavior of HA was similar to that in vivo, but in vitro behavior of $\beta$-TCP was not similar to that in vivo.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.4
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• pp.259-265
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• 2010

Purpose: This study was aimed to evaluate the effect of different sizes of $\beta$-TCP/ HA particles on vertical bone augmentation using titanium mesh in the cranium of rabbits. Materials and methods: Six white rabbits weighing 5kg were used. Four circular grooves of 6mm diameter were made by trephine, and five small holes were drilled in the inner surface of each circular gooves. Different sizes of grafts (small 0.3 - 0.5 mm, medium 0.5 - 1.0, large 1.0 - 2.0 mm) were placed respectively in the experimental groups. Titanium mesh (height 3 mm, width 6 mm) was placed. After 8weeks healing period, the rabbits were euthanized, and the specimens were prepared for histological findings. New bone formation and remaining graft area were measured to calculate the ratio of areas occupying the inner space of titanium mesh. Mann-Whitney U-test and Wilcoxon signed rank-test were used for statistical analysis ($\alpha$ = .05). Results: The experimental groups with $\beta$-TCP/HA graft showed a significantly higher new bone formation (P = .003). Comparing different sizes of $\beta$-TCP/HA, there was no statistical difference in terms of new bone formation. The vertical bone formation (i.e. new bone and graft area) was significantly greater in $\beta$-TCP/HA groups (P = .001). In comparison between different sizes of $\beta$-TCP/HA, medium size group had significantly greater area than large particle size group (P = .039). Conclusion: The use of $\beta$-TCP/HA with titanium mesh showed a higher vertical bone formation, particularly the medium sized $\beta$-TCP/HA particles (0.5 - 1.0 mm) produced better results in vertical bone augmentation.

• Korean Journal of Materials Research
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• v.25 no.4
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• pp.165-170
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• 2015

Ceramics biomaterials are useful as implant materials in orthopedic surgery. In this study, porous HA(hydroxyapatite)/${\beta}$-TCP(tricalcium phosphate) composite biomaterials were successfully fabricated using HA/${\beta}$-TCP powders with 10-30 wt% $NH_4HCO_3$ as a space holder(SH) and $TiH_2$ as a foaming agent, and MgO powder as a binder. The HA/${\beta}$-TCP powders were consolidated by spark plasma sintering(SPS) process at $1000^{\circ}C$ under 20 MPa conditions. The effect of SH content on the pore size and distribution of the HA/${\beta}$-TCP composite was observed by scanning electron microscopy(SEM) and a microfocus X-ray computer tomography system(SMX-225CT). These microstructure observations revealed that the volume fraction of the pores increased with increasing SH content. The pore size of the HA/${\beta}$-TCP composites is about $400-500{\mu}m$. The relative density of the porous HA/${\beta}$-TCP composite increased with decreasing SH content. The porous HA/${\beta}$-TCP composite fabricated with 30%SH exhibited an elastic modulus similar to that of cortical bone; however, the compression strength of this composite is higher than that of cortical bone.

• Journal of the Korean Ceramic Society
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• v.41 no.3
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• pp.202-209
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• 2004

Hydroxyapatite(HA)/TiO$_2$ composite powders were prepared by mixing of spherical TiO$_2$ (10-15 nm, 500 nm) and needle-shaped HA (50-70 nm, 120-250 nm) powders which had been synthesized through precipitation, sol-gel and hydrothermal methods. From the three types of starting composite powders (HA/TiO$_2$ wt% of 75/25, 50/50, and 25/75), dense $\beta$-TCP/TiO$_2$ composites were prepared by hot-pressing at 800-100$0^{\circ}C$ for 30 min under the pressure of 30 ㎫ in Af atmosphere. The $\beta$-TCP/TiO$_2$ composites showed different microstructures and sintering densities depending on their powder morphology, composition and sintering temperature. With increasing the sintering temperature and the content of TiO$_2$, sintered density was increased and microstructure became more homogeneous.

• Journal of Periodontal and Implant Science
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• v.39 no.sup2
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• pp.223-230
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• 2009

Purpose: Synthetic bone products such as biphasic calcium phosphate (BCP) are mixtures of hydroxyapatite (HA) and ${\beta}$-tricalcium phosphate (${\beta}$- TCP). In periodontal therapies and implant treatments, BCP provides to be a good bone reconstructive material since it has a similar chemical composition to biological bone apatites. The purpose of this study was to compare bone regeneration capacity of two commercially available BCP. Methods: Calvarial defects were prepared in sixteen 9-20 months old New Zealand White male rabbits. BCP with HA and ${\beta}$- TCP (70:30) and BCP with Silicon-substituted hydroxyapatite (Si-HA) and ${\beta}$-TCP (60:40) particles were filled in each defect. Control defects were filled with only blood clots. Animals were sacrificed at 4 and 8 week postoperatively. Histomorphometric analysis was performed. Results: BCP with HAand ${\beta}$- TCP 8 weeks group and BCP with Si-HA and ${\beta}$- TCP 4 and 8 weeks groups showed statistically significant in crease (P <0.05) in augmented area than control group. Newly formed bone area after 4 and 8 weeks was similar among all the groups. Residual materials were slightly more evident in BCP with HA and ${\beta}$- TCP 8 weeks group. Conclusions: Based on histological results, BCP with HA and ${\beta}$- TCP and BCP with Si-HA and ${\beta}$- TCP appears to demonstrate acceptable space maintaining capacity and elicit significant new bone formation when compared to natural bone healing in 4 and 8 week periods.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.9
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• pp.791-797
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• 2014

Abstract Scaffold used as a carrier of the cell has been actively conducted using plenty of technology in tissue engineering. ${\beta}$-tricalcium phosphate (${\beta}$-TCP) material has shown good biocompatibility and osteoconductive ability when it was implanted as a bone graft substitute in osseous defect in human and animal studies for bone regeneration. In this study, we fabricated the blended polycaprolactone (PCL) and ${\beta}$-TCP scaffold by the polymer deposition system (PDS). The PCL/${\beta}$-TCP scaffold was fabricated at a temperature of $110^{\circ}C$, pressure of 650 kPa, and scan velocity of 100 mm/sec. The Overall geometry and size of the scaffold were fixed circle type with a diameter of 10 mm and a height of 4 mm. PCL/${\beta}$-TCP scaffold was observed by scanning electron microscopy. Cell attachment and proliferation of the scaffold containing 30 wt% ${\beta}$-TCP was superior to those containing 10 wt% and 20 wt% ${\beta}$-TCP.

• The Journal of Advanced Prosthodontics
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• v.6 no.4
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• pp.285-294
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• 2014

PURPOSE. The purpose of this study was to evaluate the properties of a porous zirconia scaffold coated with bioactive materials and compare the in vitro cellular behavior of MC3T3-E1 preosteoblastic cells to titanium and zirconia disks and porous zirconia scaffolds. MATERIALS AND METHODS. Titanium and zirconia disks were prepared. A porous zirconia scaffold was fabricated with an open cell polyurethane disk foam template. The porous zirconia scaffolds were coated with ${\beta}$-TCP, HA and a compound of ${\beta}$-TCP and HA (BCP). The characteristics of the specimens were evaluated using scanning electron microscopy (SEM), energy dispersive x-ray spectrometer (EDX), and x-ray diffractometry (XRD). The dissolution tests were analyzed by an inductively coupled plasma spectrometer (ICP). The osteogenic effect of MC3T3-E1 cells was assessed via cell counting and reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS. The EDX profiles showed the substrate of zirconia, which was surrounded by the Ca-P layer. In the dissolution test, dissolved $Ca^{2+}$ ions were observed in the following decreasing order; ${\beta}$-TCP > BCP > HA (P<.05). In the cellular experiments, the cell proliferation on titanium disks appeared significantly lower in comparison to the other groups after 5 days (P<.05). The zirconia scaffolds had greater values than the zirconia disks (P<.05). The mRNA level of osteocalcin was highest on the non-coated zirconia scaffolds after 7 days. CONCLUSION. Zirconia had greater osteoblast cell activity than titanium. The interconnecting pores of the zirconia scaffolds showed enhanced proliferation and cell differentiation. The activity of osteoblast was more affected by microstructure than by coating materials.

• The Journal of Advanced Prosthodontics
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• v.3 no.3
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• pp.161-165
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• 2011

PURPOSE. This randomized clinical trial was conducted to assess the safety and effectiveness of the ErhBMP-2 in alveolar bone regeneration as well as preservation of the ${\beta}$-TCP bone graft material that contains ErhBMP-2. MATERIALS AND METHODS. This study involved 72 patients at the 3 study centers. The patients, who were divided into 2 groups: the experiment group who had ErhBMP-2 coated TCP/HA and the control group who had TCP/HA graft material alone transplanted immediately after tooth extraction. CT was taken before and 3 months after the transplantation and healing status was compared between the two groups. The efficacy endpoints that were used to measure the degree of bone induction included alveolar bone height and 3 measurements of bone width. The paired t test was used to determine the significance of the changes (P<.05). RESULTS. Changes in alveolar bone height were $-1.087{\pm}1.413$ mm in the control group and $-.059{\pm}0.960$ mm in the experimental group (P<.01). At 25% extraction socket length [ESL], the changes were $0.006{\pm}1.149$ mm in the control group and $1.279{\pm}1.387$ mm in the experimental group. At 50% ESL, the changes were $0.542{\pm}1.157$ mm and $1.239{\pm}1.249$ mm, respectively (P<.01 for 25% ESL, and P<.05 for 50% ESL). During the experiment, no adverse reactions to the graft material were observed. CONCLUSION. ErhBMP-2 coated ${\beta}$-TCP/HA were found to be more effective in preserving alveolar bone than conventional ${\beta}$-TCP/HA alloplastic bone graft materials.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.5
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• pp.203-207
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• 2019

Calcium phosphates such as hydroxyapatite (HAp), tricalcium phosphate (${\beta}$-TCP), and biphasic calcium phosphate (BCP, HAp/${\beta}$-TCP) have been prepared via hydrothermal treatment. The synthesis was conducted by reacting ($Ca(OH)_2$) aqueous solution with phosphoric acid ($H_3PO_4$) under different hydrothermal synthesis conditions (temperatures up to $150^{\circ}C$ and pH lower than 12). The effects of initial precursor Ca/P ratio (1.30, 1.50 and 1.67) and post heat treatment on the phase evolution behavior of the powders and sintered ceramics were investigated. The phases of resulting powders and sintered ceramics were controllable by adjusting the initial Ca/P ratio. A single HAp phase without any noticeable second phase was obtained for the initial Ca/P ratio of 1.67 in the overall heat treatment range. Pure ${\beta}$-TCP and biphasic calcium phosphate (HAp/${\beta}$-TCP) were synthesized from precursor solutions having Ca/P molar ratios of 1.30 and 1.50, respectively, after having been heat treated at $900^{\circ}C$ or higher. Dense ceramics with translucency were obtained at considerably lower sintering temperatures.

• Journal of Periodontal and Implant Science
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• v.46 no.1
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• pp.57-69
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• 2016

Purpose: The aim of this pilot study was to determine the osteoconductivity and dimensional stability of augmented sinuses using different ratios of biphasic calcium phosphate (BCP) in a rabbit sinus model. Methods: Each sinus of New Zealand white rabbits (2.5-3.5 kg) was assigned to one of two groups: BCP with a hydroxyapatite to ${\beta}$-tricalcium phosphate (HA:${\beta}$-TCP) ratio of 70:30 (group TCP30) and BCP with an HA:${\beta}$-TCP ratio of 30:70 (group TCP70). After preparing a window in the antral wall of a sinus, the Schneiderian membrane was elevated, and the applicable material was grafted. A fluorochrome calcein green was injected five days before euthanizing the animals at four months post-surgery. The specimens were analyzed histologically, histomorphometrically, and by using micro-computed tomography (micro-CT). Results: Micro-CT analysis revealed that the total augmented volume and the new bone volume did not differ significantly between the two groups whereas the resorption of materials was greater in the TCP70 group. The trabecular thickness, number, and separation also did not differ significantly between the two groups. Histomorphometrically, the areas of total augmentation, new bone, and residual material, as well as the ratio of new-bone-material contact did not differ significantly between the groups. Histologically, the residual particles were more scattered in the TCP70 group than in the TCP30 group. The fluorescence of the calcein green did not differ notably between the two groups. Conclusions: The osteoconductivity and dimensional stability of the two BCPs with different ratios tested in this study were comparable after four months of healing. Therefore, we conclude that both BCPs show promise as a bone substitute for sinus augmentation.