• Title/Summary/Keyword: Hydroxyapatite (HAP)

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Addition of Hydroxyapatite to Toothpaste and Its Effect to Dentin Remineralization

  • Sadiasa, Alexander;Jang, Dong-Woo;Nath, Subrata Deb;Seo, Hyung Seok;Yang, Hyn Mo;Lee, Byong Taek
    • Korean Journal of Materials Research
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    • v.23 no.3
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    • pp.168-176
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    • 2013
  • In this study, hydroxyapatite (HAp) was incorporated into toothpaste and its effect on the remineralization and restoration of dental enamel was evaluated. Different sets of toothpaste were incorporated with HAp levels of 0%, 5%, 10 %, and 15 %. The filler particles of the resulting toothpaste samples were observed via SEM and XRD and compared with compositions of several commercially available toothpastes, showing that the HAp was successfully incorporated into the toothpaste samples. Different sets of human enamel were inflicted with lesions and then treated with the different fabricated toothpaste samples for five minutes three times a day for seven days. During the treatment, the teeth were subjected to demineralization and remineralization cycles to simulate the effect of natural saliva. The surface of the enamel samples were observed using SEM before and after one week of treatment, showing the formation of HAp layers on the surfaces of the enamel samples. The effect of the toothpaste on the lesions was observed using an inverted light microscope and the lesion depth was found to decrease as the concentration of HAp in the toothpaste used increased. HAp was successfully incorporated in the toothpaste and its presence was found to lessen lesion depths and improve tooth remineralization.

Effect of MgO-P2O5 Sintering Additive on Microstructure of Sintered Hydroxyapatite (HAp) Bodies and Their In-Vitro Study

  • Lee, Byong-Taek;Youn, Hyeong-Chul;Lee, Chi-Woo;Song, Ho-Yeon
    • Korean Journal of Materials Research
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    • v.17 no.2
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    • pp.100-106
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    • 2007
  • The effects of $MgO-P_2O_5$ based sintering additive on the microstructure and material and biological properties of hydroxyapatite $(HAp,\;Ca_{10}(PO_4)_6(OH)_2)$ ceramic were investigated using XRD, SEM and TEM techniques. The $MgO-P_2O_5$ sintering additive improved the material properties and increased the grain size in the sintered HAp bodies. As the content of sintering additive increased over 4 wt%, a small amount of the HAp phase was decomposed and transformed to ${\beta}-TCP$. In the 2 wt% $MgO-P_2O_5$ content HAp sintered body, the maximum values of density and hardness were respectively about 3.10 gm/cc and 657 HV. However, the maximum fracture toughness in the HAp body containing 8 wt% $MgO-P_{2}O_{5}$ was about $1.02MPa{\cdot}m^{1/2}$ due to the crack deflection effect. Human osteoblast like MG-63 cells and osteoclast like raw 264.7 cells were well grown and fully covered all of the HAp sintered bodies. The osteoblast cells were grown with spindle-shaped and the osteoclast cells had a grape-like round shape.

A Study of Hydroxyapatite Production from Waste Oyster Used Mechanochemical Treatment

  • Kim, Sun-Tae;Oh, Chi-Jung;Kim, Wan-Tae;Kim, Young-Sig;Kim, Myong-Jun
    • Proceedings of the IEEK Conference
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    • 2001.10a
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    • pp.469-471
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    • 2001
  • Dry grinding of a mixture of CaCO$_3$ and Ca(H$_2$PO$_4$)$_2$.$H_2O$ was conducted using a planetary ball mill in order to investigate solid state reaction for a synthesis of hydroxyapatite(Ca$_{10}$(PO$_4$)$_{6}$(OH)$_2$, HAp) through mechanochemical treatment method. The raw materials, which are composed of waste oyster and calcium biphosphate Ca(H$_2$PO$_4$)$_2$.$H_2O$, were mixed and then treated mechanochemically. The synthesis of hydroxyapatite(Ca$_{10}$(PO$_4$)$_{6}$(OH)$_2$, HAp) from the mixture was almost completed by about 60 minute grinding. The formation of HAp monophase in the ground mixture was characterized through X-ray diffraction (XRD) analysis. Moreover, the formation of HAp monophase depending on the grinding time was improved by increasing the grinding time.ime.ime.

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The ESCA Analysis of Hydroxyapatite Thin Films Deposited by RF Sputtering (RF 스퍼터링으로 증착된 하이드록시아파타이트 박막의 ESCA 분석)

  • Jung, Chan-Hoi;Lee, Jun-Hee;Kim, Soon-Kook;Kim, Myung-Han;Yu, Jae-Keun;Kim, Seung-Eon
    • Korean Journal of Materials Research
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    • v.16 no.4
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    • pp.264-271
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    • 2006
  • RF sputtering process was applied to produce thin hydroxyapatite(HAp) films on Ti-6Al-4V alloy substrates. The effects of different heat treatment conditions on the chemical composites between HAp thin films and Ti-6Al-4V alloy substrates were studied. After deposition, the HAp thin films were heat treated for 1h at $400^{\circ}C,\;600^{\circ}C\;and\;800^{\circ}C$ under the atmosphere, and analyzed O/M, FESEM-EDX and ESCA, respectively. Experimental results represented that interface of HAp thin films and Ti-6Al-4V alloy substrates was composed Ti-OH, TiO, TiN, $Al_2O_3,\;V_2O_3,\;VO_2$. pyrophosphate and decreased carbide followed by the increase of heat treatment temperature.

Ag Impregnated HAp Coatings on Alumina Substrate by IBAD and Its Biological Test (IBAD를 이용하여 알루미나 위에 HAp를 Coating하는 연구와 이의 항균력 시험)

  • Park, Eui-Seo;Kim, Taik-Nam;Yim, Hyuk-Jun;Kim, Yun-Jong;Hwang, Deuk-Soo;Kim, Jung-Woo;Kim, Sun-Ok
    • The Journal of Engineering Research
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    • v.3 no.1
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    • pp.181-187
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    • 1998
  • Hydroxyapatite was used as implant materials, because it has a good biocompatibility and is similar to human bone. However it is not expected to have a high strength as implant materials because of a low fracture strength after sintering of HAp. Alumina ($\alpha$-alumina) shows a stable chemical properties and high strength in physiological environments. Thus it was tried to use a HAp coatings on Alumina substrate as implant materials. In this study, HAp was coated on Alumina substrate by lon Beam Assisted Deposition(IBAD). Then Ag was impregnated on HAp coating layer, which showed antimicrobial effects. To carry out the ion exchange of $Ag^+$ with $Ca^{2+}$ in HAp on the surface, HAp coated alumina substrate was immersed in 20ppm, 100ppm $AgNO_3$ solution at room temperature for 48 hours. Antimicrobial test was studied by using bacteria, which normally caused periprosthetic infections. The follwing bacteria was used in antimicrobial test. Escherichia coli, Pseudomonas aeruginosa (gram negative) and staphylococcus epidermidis (gram positive). Ag impregnated HAp shows very good antimicrobial effects against these bacteria. The surface structure of sample, which was treated in $AgNO_3$ solution was studied by SEM, XRD. Ag release curve was studied in Simulated Body Fluid (SBF) solution.

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Characteristics according to the Amount of HAp Added in Resin for Tooth Repair

  • Hwang, Sungu;Lim, Jinhyuck;Ryu, Suchak
    • Journal of the Korean Ceramic Society
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    • v.56 no.6
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    • pp.521-525
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    • 2019
  • A study was conducted to investigate the possibility of a composite material containing a composite resin as a matrix and hydroxyapatite (HAp) powder as a substitute material for tooth repair. As the content of HAp increased, hardness value (111.9 HV at 9%) increased and flexural strength (73.3 MPa at 9%) decreased. Observation of the microstructure after immersion in a simulated body fluid (SBF) solution confirmed a dense structure due to mutual coagulation and curing. It was thought that fine HAp recrystals were formed with the lapse of time, and they were entangled to form a condensation structure and had a dense structure. In addition, since the activity was shown by the ion migration on the surface of a tooth, it was highly likely that a biocompatible bond occurred during tooth contact. Therefore, it could be used as a substitute material for tooth repair.

Fabrication of CNT-Reinforced HAp Composites by Spark Plasma Sintering

  • Sarkar, Swapan Kumar;Youn, Min-Ho;Oh, Ik-Hyun;Lee, Byong-Taek
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.1082-1083
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    • 2006
  • Carbon nanotube (CNT) reinforced hydroxyapatite (HAp) composites were fabricated by using the spark plasma sintering process with surfactant modified CNT and HAp nano powder. Without the dependency on sintering temperature, the main crystal phase existed with the HAp phase although a few contents of ${\beta}-TCP$ (Tri calcium phosphate) phase were detected. The maximum fracture toughness, $(1.27\;MPa.m^{1/2})$ was obtained in the sample sintered at $1100^{\circ}C$ and on the fracture surface a typical intergranular fracture mode, as well as the pull-out pmhenomenon of CNT, was observed.

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Microstructures of HAp and HAp-Ag Composite Coating Layer Prepared by RS Magnetron Sputtering (RE Magnetron Sputtering에 의해 제조된 HAp와 HAp-Ag복합코팅층의 미세조직)

  • Lee, Hee-Jung;Oh, Ik-Hyun;Park, Sang-Shik;Lee, Byong-Taek
    • Journal of the Korean Ceramic Society
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    • v.41 no.4
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    • pp.328-333
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    • 2004
  • Hydroxyapatite (HAp) and HAp-Ag composite layers were coated on ZrO$_2$and Si wafer substrates by RF magnetron sputtering technique. The thickness of coating layers was in the range of 0.7∼1.0$\mu\textrm{m}$ and its roughness was 3∼4nm. The heat treated HAp coating layers were composed with nano-sized crystallines. However, the HAp-Ag composite layers showed the mixed structure with crystalline and amorphous phases. The Ca/P ratio of the as-received HAp coating layer was 1.9, but, the value was decreased as the Ag content with increased. Also, the Vickers hardness of HAp coating layer decreased as the Ag content increase.

The Sorption Kinetic Studies and Development of Mixed Culture for Removal of Nonpoint Pollution Source (비점오염원 처리를 위한 혼합여재의 개발 및 흡착 Kinetic 연구)

  • Chung, Woojin;Lee, Sijin
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.4
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    • pp.37-44
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    • 2012
  • This study investigated on the adsorption of nonpoint pollution source using the Sand, hydroxyapatite(HAP), Zeolite and mixed culture. The adsorption of nonpoint pollution source on Sand, hydroxyapatite(HAP), Zeolite and mixed culture was investigated during a series of batch adsorption experiments. After the batch absorption experiments analysed COD, T-N, T-P on adsorption water. The experimental data was analysed using the pseudo-first-order adsorption kinetic models. Langmuir and Freundlich isotherm models were tested for their applicability. The maximum adsorbed amount $(Q_{max})$ of COD were found to be sand 0.0511mg/g, HAP 0.1905mg/g, Zeolite 1.0366mg/g and Mixed media 0.7444mg/g. The maximum adsorbed amount $(Q_{max})$ of T-N were found to be sand 0.0159mg/g, HAP 0.0537mg/g, Zeolite 0.5496mg/g and Mixed media 0.1374mg/g. The maximum adsorbed amount $(Q_{max})$ of T-P were found to be sand 0.0202mg/g, HAP 0.1342mg/g, Zeolite 0.0462mg/g and Mixed media 0.1180mg/g. As a result, the mixed media was effective to remove nonpoint pollution source.

The Effects of HAp and BCP Nano Powders Synthesized by Microwave-Assisted Synthesis on the Activation of Osteoblast and Osteoclast (마이크로웨이브법에 의해 제조된 HAp 및 BCP 분말이 뼈모세포 및 파골세포의 활성에 미치는 영향)

  • Song, Ho-Yeon;Min, Young-Ki;Yang, Hun-Mo;Mang, Joo-Yang
    • Korean Journal of Materials Research
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    • v.17 no.12
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    • pp.669-675
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    • 2007
  • Hydroxyapatite (HAp) and biphasic calcium phosphate (BCP) nano powders were synthesized using the microwave-assisted synthesis process dependent on pH and microwave irradiation time. The average size of a powder was less than 100 nm in diameter. Through in-vitro cytotoxicity tests by an extract dilution method, the HAp and BCP nano powders have shown to be cytocompatible for L-929 fibroblast cells, osteoblastlike MG-63 cells and osteoclast-like Raw 264.7 cells. The activation of osteoblast was estimated by alkaline phosphatase (ALP) activity. When the HAp and BCP were treated to MG-63 cells, alkaline phosphatase activities increased on day 3, compared with those of the untreated cells. Also, the collagen fibers increased when the HAp and BCP powders suspension were treated to MG-63 cells, compared to those of the untreated cells. Quantitative alizarin red S mineralization assays showed a trend toward increasing mineralization in osteoblast cultured with powder suspension. In conclusion, hydroxyapatite and biphasic calcium phosphate appeared to be a bone graft substitute material with optimal biocompatibility and could be further applied to clinical use as an artificial bone graft substitute.