Journal articles: 'Hydroxyapatite Testing'

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Akbar, Achmad Fitriadi, and Sari Edi Cahyaningrum. "Characterization and Anti-Bacterial Activity Testing of the Nano Hydroxyapatite-Clove (Eugenia Caryophyllus) Against Streptococcus Mutans Bacteria." Indonesian Journal of Chemical Science 11, no. 1 (May 1, 2022): 1–8. http://dx.doi.org/10.15294/ijcs.v11i1.51037.

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Hydroxyapatite is one of the materials as a source of calcium and phosphate in the tooth remineralization process. Several studies have shown that hydroxyapatite produces strong antibacterial activity against caries-causing bacteria. Dental caries are one of the tooth scrapings suffered by many people. Dental caries are caused by Streptococcus mutans. In addition to hydroxyapatite, essential oil derived from cloves also has a good antimicrobial function. The eugenol content in cloves can kill bacteria that are resistant to antibiotics. This study aims to determine the results of the physicochemical characterization and antibacterial test of Streptococcus mutans in the clove-hydroxyapatite nanoformulation. This study used a nano-hydroxyapatite-clove test material with various compositions of 0.5 mL, 1 mL, 2 mL, 3 mL, and 4 mL of clove oil, 1% hydroxyapatite, Tween, and propylene glycol. The results of FT-IR characterization showed OH, C-H, C-O, C=O, PO43-, and CO32- functional groups. In PSA testing, the smallest size is indicated by the variation in the composition of 1ml clove oil, which is 16.07nm. The measurement of the antibacterial activity test showed that the hydroxyapatite-clove nanoformulation was able to inhibit the growth of Streptococcus mutans bacteria, with normally distributed data (p=0,05) and produce a significant probability,000 (p<0,05).

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Suciu, Oana, Liviu Bereteu, Gheorghe Drăgănescu, and Teodora Ioanovici. "Determination of the Elastic Modulus of Hydroxyapatite Doped with Magnezium through Nondestructive Testing." Advanced Materials Research 814 (September 2013): 115–22. http://dx.doi.org/10.4028/www.scientific.net/amr.814.115.

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In this paper there are presented determination methods of longitudinal elasticity modulus based on processing and analysis of vibration signals which are the results of an impulse from a small rigid ball applied on some samples of hydroxyapatite with discoid form. Hydroxyapatite is a bioactive bioceramics used, usually in implants, rods and screws covering, in order to allow human tissue to adhere to implant surface. In order to improve mechanical properties of hydroxyapatite it is doped with magnesium. This chemical element exists in normal bone tissue; it doesnt create any compatibility problem and has a stabilizing role in heat treatments stopping undesirable phase transformations.

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Gross, K. A., and C. C. Berndt. "In vitro testing of plasma-sprayed hydroxyapatite coatings." Journal of Materials Science: Materials in Medicine 5, no. 4 (April 1994): 219–24. http://dx.doi.org/10.1007/bf00121092.

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Lawarti, Riska Amelia, and Sari Edi Cahyaningrum. "Potential Antibacterial Activity of Hydroxyapatite Composite And Green Betel Leaf Extract (Piper betle L.) Against Streptococcus mutans Bacteria." Indonesian Journal of Chemical Science 11, no. 1 (May 1, 2022): 41–49. http://dx.doi.org/10.15294/ijcs.v11i1.51059.

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Dental caries is a common oral disease and the main bacteria causing it is Streptococcus mutans. Hydroxyapatite is a material consisting of calcium and phosphate components that have dual abilities as remineralizing and antibacterial agents. In addition to hydroxyapatite, phenolic compounds and tannins in green betel leaf extract also have antimicrobial functions. Tannins and phenols act as poisons for microbes by inhibiting the enzyme activity of interfering microbes. The purpose of this study was to determine the physicochemical character and antibacterial activity of Streptococcus mutans from oral hydroxyapatite preparations and green betel leaf extract. In this study, hydroxyapatite and green betel leaf extract were used as oral preparations with variations in the addition of green betel leaf extract 0.1; 0.3; 0.5; 0.7 and 1 gram. The results of the FTIR analysis explain the absorption bands of the functional groups PO43-, OH and CO32- from hydroxyapatite, as well as the C=O and C-O groups from green betel leaf extract which have shifted the wave number, indicating that there has been a bond between hydroxyapatite and metabolite compounds in betel leaf extract. green. In PSA testing, the smallest particle size was indicated by the variation of hydroxyapatite composite and 0,3 gram green betel leaf extract, which was 690.08 nm. Testing the antibacterial activity of the hydroxyapatite-green betel leaf extract composite showed inhibitory activity against Streptococcus mutans bacteri.

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Burmawi, Novesar Jamarun, Syukri Arief, and Gunawarman. "Caracterization and Compressive Strength of Biocomposite Hydroxyapatite-Borosilicate with Hight Temperature Sintering." MATEC Web of Conferences 248 (2018): 01005. http://dx.doi.org/10.1051/matecconf/201824801005.

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The use of Hydroxyapatite as bone graft material continues to increase. To utilize hydroxyapatite, it is often formed into biocomposite. The formation of hydroxyapatite biocomposite intended to address the fragile hydroxyapatite weaknesses. The added element in the formation of this biocomposite is borosilicate. Mixing of this material is arranged with certain composition using ball miling. To form a test specimen, it was printed with compacting force of 5 KN, 15 KN and 25 KN. Test results Compressive Strength.and XRD showed that addition of borosilicate did not change the compound that is hydroxyapatite, but the intensity of hydroxyapatite tends to decrease with addition of borosilicate amount, this is corroborated by FTIR testing. For visible compressive strength, the maximum value occurs at 75: 25 compositions, ie 45 MPa, 42.9 MPa and 52.3 MPa. This suggests that the addition of borosilicate in biocomposite formation does not alter hydroxyapatite compound and can generally increase the compressive strength and modulus of elasticity to 25% wt% borosilicate addition.

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Faisal, Hendri, Rida Evalina Tarigan, and Julkardo Lase. "Antibacterial Activity of Ag-Hidroxyapatite Composite of Bone-in Tuna (Thunnus albacores) Against Streptococcus mutans." JURNAL SAINS NATURAL 12, no. 2 (April 29, 2022): 78. http://dx.doi.org/10.31938/jsn.v12i2.378.

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Calcium from fish bones have not been widely used for human needs. Calcium in the medical field is used as a hydroxyapatite compound, such as in the manufacture of bones and dentures, as an additive in the manufacture of toothpaste, and usage in drug delivery. This study aims to determine whether the Ag-Hydroxyapatite composite has an inhibitory capability against Streptococcus mutans bacteria. This research is an experimental study through laboratory testing by synthesizing Ag-Hydroxyapatite from tuna fish bones (Thunnus albacores) and testing its antibacterial activity against Streptococcus mutans bacteria. The results showed that the tuna fish bone samples formed hydroxyapatite compounds and the results of the Ag-Hydroxyapatite composite had antibacterial activity against Streptococcus mutans bacteria, the statistical test results showed a significant difference from the negative control group. Ag-hydroxyapatite composite has antibacterial activity against Streptococcus mutansKeywords: Tuna (Thunnus albacores); Hydroxyapatite; Argentum; Antibacterial; Streptococcus mutans ABSTRAKUji Aktivitas Antibakteri Komposit Ag-Hidroksidaapatit dari Tulang Ikan Tuna (Thunnus albacores) terhadap Streptococcus mutansKalsium dari tulang ikan, belum banyak dimanfaatkan untuk kebutuhan manusia. Kalsium dalam dunia medis dimanfaatkan menjadi senyawa Hidroksiapatit. seperti pada pembuatan tulang dan gigi palsu, sebagai bahan tambahan dalam pembuatan pasta gigi dan juga digunakan sebagai penghantar obat. Penelitian ini bertujuan untuk mengetahui apakah komposit Ag-Hidroksiapatit memiliki daya hambat terhadap bakteri Streptococcus mutans. Penelitian ini merupakan penelitian yang bersifat eksperimental melalui pengujian laboratorium dengan mensintesis Ag-Hidroksiapatit dari tulang ikan tuna (Thunnus albacores) dan menguji aktivitas antibakteri terhadap bakteri Streptococcus mutans. Hasil penelitian menunjukan bahwa dari sampel tulang ikan tuna terbentuk senyawa Hidroksiapatit dan hasil komposit Ag-Hidroksiapatit memiliki aktifitas antibakteri terhadap bakteri Streptococcus mutans, hasil uji statistik menunjukkan adanya perbedaan signifikan terhadap kelompok kontrol negatif. Komposit Ag-hidrokiapatit memiliki aktifitas antibakteri terhadap bakteri Streptococcus mutansKeywords: Tuna (Thunnus albacores); Hydroxyapatite; Argentum; Antibacterial; Streptococcus mutans

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R., Dr Mohammed. "Assessment of shear bond strength of Polycarboxylate cement reinforced by different amounts of Hydroxyapatite." Mustansiria Dental Journal 7, no. 2 (March 19, 2018): 161–65. http://dx.doi.org/10.32828/mdj.v7i2.393.

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This study was done to assess bond strength of Polycarboxylate cement reinforcedby different amount of Hydroxyapatite. In this study a hydroxyapatite materials wereadded to Polycarboxylate cement at different ratios;10%, 15%, 20%, 25% and 30% (by weight ) and the bond strength was detected by construction a cylinders from thesemixed materials, constructed on exposed dentine of human extracted premolar teethand by Zwick’s universal testing machine the bond strength were detected for thesemixed materials. Results showed that the Polycarboxylate reinforced byhydroxyapatite has higher bond strength than conventional Polycarboxylate cementand the hydroxyapatite powder to Polycarboxylate cement powder ratio by weightbest to be 20%. The addition of hydroxyapatite to conventional Polycarboxylatecement increased its bond strength to dentine.

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Chen, P., X. Chen, Y. Wang, and P. Wang. "Preliminary study on the upcycle of non-structural construction and demolition waste for waste cleaning." Materiales de Construcción 70, no. 338 (April 15, 2020): 220. http://dx.doi.org/10.3989/mc.2020.13819.

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This study proposes a method to convert non-structural calcium-rich construction and demolition waste fines into adsorbents of heavy metal ions by mixing waste fines with diammonium hydrogen phosphate solution to produce hydroxyapatite, which has high surface areas and excellent ion-exchange capacity with heavy metal ions. As a result, environmental polluting waste is converted into environmentally cleaning material. Waste putty powders was chosen as the representative waste to investigate the detailed formation process of hydroxyapatite and the key reaction parameters of the reaction. Results showed that hydroxyapatite can be produced on waste putty particles. Higher ageing temperatures or longer ageing duration are beneficial to the yield and crystallinity of the produced hydroxyapatite. Adsorption testing confirmed that Ni2+ can replace Ca2+ in the hydroxyapatite lattice, leading to the formation of a new crystal, arupite (Ni3(PO4)2•8H2O), and contributing to a modest adsorption capacity for Ni2+ (15 mg/g) for the hydroxyapatite-containing waste putty.

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Narayan, Roger J. "Hydroxyapatite/diamondlike Carbon Nanocomposites: A Novel Surface Modification to Extend Orthopaedic Prosthesis Lifetimes." Journal of Materials Research 20, no. 9 (September 2005): 2288–95. http://dx.doi.org/10.1557/jmr.2005.0284.

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Conventional plasma-sprayed hydroxyapatite coatings suffer from many difficulties that have limited their use in orthopaedic implants, including uneven resorption rates, poor fracture toughness, and poor adhesion to medical alloys. The placement of a diamondlike carbon buffer layer may overcome these obstacles by providing unique chemical inertness, hardness, and cell-interaction properties at the implant–tissue interface. Nanocrystalline hydroxyapatite and amorphous diamondlike carbon films were prepared by room-temperature pulsed-laser deposition of hydroxyapatite and graphite targets, respectively. Scanning electron microscopy, transmission electron microscopy, x-ray diffraction, and microscratch adhesion testing were used to determine surface morphology, interfacial structure, and adhesion of the bilayer coatings. Nanocrystalline hydroxyapatite/diamondlike carbon coatings have several potential orthopaedic applications, including use in hip prostheses.

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Bao, Quan He, Chao Sun, Chen Zhang, and Jie Qing Zhang. "Dip Coated Magnesium-Substituted Hydroxyapatite Coatings on Magnesium Alloy for Biomedical Applications." Journal of Biomimetics, Biomaterials and Biomedical Engineering 25 (October 2015): 83–89. http://dx.doi.org/10.4028/www.scientific.net/jbbbe.25.83.

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Magnesium-substituted hydroxyapatite coatings have been deposited on magnesium alloy for biomedical applications by sol–gel technology. The Ca(10−x)Mgx(PO4)6(OH)2 coatings obtained, with magnesium contents up to x = 1.5, show dense and compact and with visible cracks. The results of Hydrogen (H2) evolution testing in Hank’s solution show that magnesium-substituted hydroxyapatite coatings can improve the corrosion resistance of magnesium alloy.

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Marković, D., V. Živojinović, V. Koković, and V. Jokanović. "Hydroxyapatite as a Root Canal System Filling Material: Cytotoxicity Testing." Materials Science Forum 453-454 (May 2004): 555–60. http://dx.doi.org/10.4028/www.scientific.net/msf.453-454.555.

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Cao, H. D., Yan Fei Tan, Xiao Yan Lin, Hong Song Fan, and Xing Dong Zhang. "Cytocompatibility Testing of Hydroxyapatite/Collagen Composite Cross-Linked with Glutaraldehyde." Key Engineering Materials 288-289 (June 2005): 223–26. http://dx.doi.org/10.4028/www.scientific.net/kem.288-289.223.

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Glutaraldehyde was increasingly used to improve the stability of the collagen-based biomaterials as cross-linking. To investigate in vitro cytotoxicity of Hydroxyapatite/Collagen (HA/COL) composite with glutaraldehyde (GA) as cross-link reagent, which was abbreviated as cHA/COL, the mouse fibroblasts L929 cell was selected. The method of MTT colorimetric assay was adopted to evaluate the availability of cells. After cultured for 24h、 48h, the attachment and morphology of L929 cell on the surface of this material were observed by scanning electron microscopy (SEM) and fluorescent microscopy. MTT analysis indicated L929 cells cultured on cHA/COL had a perfect growth capacity. Cells proliferated well and cell colonization was observed on the materials by scanning electron microscopy and fluorescent microscopy. It demonstrated that cHA/COL composite exhibited good cytocompatibility and might be suitable as bone substitutes. The result provided the evidence for further animal experiment in vivo.

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Sirait, M., K. Sinulingga, N. Siregar, M. E. Doloksaribu, and Amelia. "Characterization of hydroxyapatite by cytotoxicity test and bending test." Journal of Physics: Conference Series 2193, no. 1 (February 1, 2022): 012039. http://dx.doi.org/10.1088/1742-6596/2193/1/012039.

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Abstract Hydroxyapatite has been synthesized as a bone graft material by analyzing the membrane made according to the cytotoxicity test and bending test. The method used is dry ball milling. Cytotoxicity testing was carried out by making isolated osteoblast cells cultured in a 75 cm2 cell flask containing a minimum of essential media. Based on the cytotoxicity test, it was found that hydroxyapatite is not toxic with cell viability above 60% (non-toxic requirements ISO 10993-5). From the variation of the hydroxyapatite mixture used, the average cell viability was (100.48 ± 11.98)%. A mixture of 2.5% Ag and 5% Ag with hydroxyapatite also provides good viability, which is above 60%, which means it is not toxic. The results of the analysis of the bending test and the compressive test showed that the larger the hydroxyapatite mixture, the lower the bending and compressive test results. The maximum bending test on a 10% mixture is 22.1 M.Pa and the compressive test on a 5% mixture is 16 °ShD.

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Nascimento, L., M. Medeiros, J. Calasans-Maia, A. Alves, Antonella M. Rossi, Gutemberg Alves, J. M. Granjeiro, and M. Calasans-Maia. "Osseoinduction Evaluation of Hydroxyapatite and Zinc Containing Hydroxyapatite Granules in Rabbits." Key Engineering Materials 493-494 (October 2011): 252–57. http://dx.doi.org/10.4028/www.scientific.net/kem.493-494.252.

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This study investigated the osteoinductive potential of granules of stoichiometric hydroxyapatite (HA) and 0.5% zinc containing hydroxyapatite (ZnHA) in intramuscular (IM) site of rabbit’s abdomen. The biomaterials were both used in granular form, with 75% porosity and particle diameter between 450 and 500μm, sintered at 1100°C. Both materials performed adequately on a multiparametric in vitro cytocompatibility assay, indicating their suitability for in vivo testing. After approval by the Ethics Commission on Teaching and Research in Animals, fifteen rabbits were submitted to general anesthesia, incision and tissue dilatation, and a small site was created for HA (right incision) and ZnHA (left incision) intramuscular implantation. The animals were killed after 2, 4 and 12 weeks for biomaterials and surrounding tissues removal. Histological analysis after 2 weeks revealed the presence of granulation tissue surrounding biomaterials with multinucleated giant cells and no newly formed bone for both materials. After 4 weeks there was fibrous tissue involving the material and few inflammatory cells. Following 12 weeks it was observed the presence of connective tissue surrounding the biomaterial, cellularized enough for the two experimental groups, but it was not observed the presence of bone matrix associated with the biomaterials. We conclude that both biomaterials are cytocompatible and did not present the property of osseoinduction after 12 weeks of implantation.

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Wongmaneerung, Rewadee. "Effect of M-Type Hexaferrites on Mechanical and Magnetic Properties of Hydroxyapatite Ceramics." Key Engineering Materials 751 (August 2017): 611–16. http://dx.doi.org/10.4028/www.scientific.net/kem.751.611.

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The overall aim of this study is to establish the inter-relationships between phase formations, mechanical properties and magnetic properties of the novel ceramic in hydroxyapatite system for biomaterial applications. First, barium hexaferrite and strontium hexaferrite powders were prepared as M-type hexaferrite phases. Hydroxyapatite was prepared from cockle shells via co-precipitation method. After that, a combination between hydroxyapatite+barium hexaferrite and hydroxyapatite+strontium hexaferrite was mixed together then shaping and sintering at 1200 °C for 2 h. The sintered samples were characterized phase formation, mechanical and magnetic properties by using X-ray diffraction (XRD), Universal testing and VSM measurements, respectively. XRD patterns for all samples showed a combination between hydroxyapatite and hexaferrite phases. Compressive strength of all samples tends to increase with increasing of the amount of hexaferrite phases due to densification mechanism. However, the increasing of these values, it appears that there is no difference in the statistical significant. For magnetic properties, the coexistence of barium hexaferrite and strontium hexaferrite phases reveals magnetic hysteresis loops, showing the change from diamagnetic to ferromagnetic behavior.

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Djustiana, Nina, Elin Karlina, Arief Cahyanto, Zulia Hasratiningsih, and Rosidah Nurhayati. "Uji Kekerasan Resin Komposit Olahan Sendiri dengan Filler Hidroksiapatit dari Tulang Ikan Air Tawar." Jurnal Material Kedokteran Gigi 7, no. 2 (September 1, 2018): 45. http://dx.doi.org/10.32793/jmkg.v7i2.372.

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Resin composite is one of the restoration materials used in dentistry. The study toward resin composite was being done to improve mechanical properties and the biocompatibilities, one of the ways by using hydroxyapatite filler. State of the aim of this study was to evaluate the hardness number of resin composite with hydroxyapatite filler from fresh water fish bones. The study was true experimental using five samples of resin composites processed with hydroxyapatite filler from fresh water fish bones and five samples of fabricated resin composites (GC Solare P) as a control. Hardness was evaluated using the Vickers microhardness testing machine (Leco). The average hardness number of resin composite processed was 18.384 VHN and resin composite made by factory was 27.952 VHN. The results were analyzed statistically by t independent (α=0.05) and showed significantly difference between resin composite processed with hydroxyapatite filler from fresh water fish bones compared to fabricated resin composite. The conclusion from this study showed that the hardness number of resin composite processed with hydroxyapatite filler from fresh water fish bone is lower than fabricated resin composite.

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Goranova, Kristina L., Anne Kathrine Kattenhøj Sloth Overgaard, and Ivan Gitsov. "Hydroxyapatite-poly(d,l-lactide) Nanografts. Synthesis and Characterization as Bone Cement Additives." Molecules 26, no. 2 (January 15, 2021): 424. http://dx.doi.org/10.3390/molecules26020424.

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This paper reports the creation of hydroxyapatite/polyester nanografts by “graft-from” polymerization of d,l-lactide with [Ca5(OH)(PO4)3]2 as the initiator and tin(II)-2-ethylhexanoate as the catalyst. Model polymerizations were performed with cyclooctanol as initiator to confirm the grafting on the surface of the hydroxyapatite nanocrystals. Polymers with the highest molecular mass (Mn) between 4250 Da (cyclooctanol) and 6100 Da (hydroxyapatite) were produced. In both cases the molecular mass distributions of the polymers formed were monomodal. The materials obtained were characterized by size-exclusion chromatography, NMR and FT-IR spectroscopy, and thermal methods. Their suitability as additives for commercial bone cement (Simplex P Speedset, Stryker Orthopaedics) has been confirmed by thermal analysis techniques and mechanical testing. The results obtained show that addition of the hydroxyapatite/ polyester nanografts improved both thermal and mechanical properties of the bone cement.

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Sirajunisha, H., A. Krishnaveni, D. Sellathamil Selvaraj, and T. Balakrishnan. "Cationic and Anionic Substitutions in the Antibacterial and Biocompatibility Properties of Sol-Gel Derived Hydroxyapatite Nanocomposites." Journal of Scientific Research 66, no. 05 (2022): 103–19. http://dx.doi.org/10.37398/jsr.2022.660514.

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This paper deals the synthesis and characterization of Pure Hydroxyapatite (Pure HAp) nanopowderan its nanocomposites. Hydroxyapatite - Zinc (HAp-Zn), Hydroxyapatite - Manganese (HAp-Mn) Hydroxyapatite - Titanium (HAp-Ti) and Hydroxyapatite - reduced Graphene oxide (HAp-rGO). The impact of Zn, Mn, Ti and rGO on the underlying, morphological, antimicrobial property and biocompatibility of hydroxyapatite nanopowders are contemplated. The structural characterization analysed through XRD. Pure HAp, HAp-Ti and HAp-rGO displayed hexagonal structure and fuse of Zn and Mn in the host lattice changed the construction into orthorhombic and rhombohedral. The normal crystallite size goes from 51 nm to 37 nm for different nanocomposites. The consolidation of cations (Zn2+ Mn2+ and Ti4+) and anion (CO3 2- ) diminished the crystallite size. Blended nanocomposites has hexagonal construction though there is hexagonal to orthorhombic progress in HAp-Zn and hexagonal to rhombohedral change in HAp-Mn nanocomposites The presence of functional groups in the samples is investigated utilizing FTIR examination. Surface morphology and compound organizations are examined utilizing Scanning Electron Microscope (SEM) and Energy Dispersive X-beam investigation (EDX) individually. The in-vitro antibacterial exercises and biocompatibility of the combined hydroxyapatite and its nanocomposite are examined utilizing Kirby-Bauer antibacterial testing and MTT assay individually. The outcomes show that Titanium and reduced Graphene Oxide fused hydroxyaptite nanocomposites are more harmful against every bacterial strain and didn't show any harmfulness against living tissues.

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Harahap, Kholidina Imanda, Henniza Rahmi, and Metta Winni. "Effect of Hydroxyapatite Synthesized from Tilapia Fish Scale Waste on the Shear Bond Strength of GIC and RMGIC to Enamel Layer (<i>In Vitro</i> Study)." Materials Science Forum 1069 (August 31, 2022): 135–43. http://dx.doi.org/10.4028/p-i3ag7g.

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Indonesia is a country that has many types of freshwater fish, one of which is tilapia. The consumption of tilapia among the people of Indonesia is quite high. So that, it will produce a lot of fish scale waste. Fish scales can be used as a natural source of hydroxyapatite because they contain calcium. The aim of this study was to evaluate the effect of hydroxyapatite synthesized from tilapia fish scale (Oreochromis niloticus) on the shear bond strength of glass ionomer cement and resin modified glass ionomer cement to enamel layer. Hydroxyapatite was synthesized from tilapia fish scale (Oreochromis niloticus) by calcination method at 800°C. Sample was made from glass ionomer cement (GIC) and resin modified glass ionomer cement (RMGIC) combined with 2, 5 and 8%wt of hydroxyapatite, respectively. Sample was bonded to enamel layer of human premolar tooth. The shear bond strength of sample was tested by using Universal Testing Machine. The result showed that shear bond strength were increased for higher concentration of hydroxyapatite that added to glass ionomer cement or resin modified glass ionomer cement. The maximum of shear bond strength of GIC Group is 6,38 ± 0,05MPa after 8%wt hydroxyapatite addition. The maximum of shear bond strength of RMGIC Group is 6,59 ± 0,06 MPa after 8%wt hydroxyapatite addition. There were significance differences among all group tested (p <0.05). It can be concluded that hydroxyapatite synthesized from tylapia fish scale can increase the shear bond strength of glass ionomer cement and resin modified glass ionomer cement.

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Behnamghader, Aliasghar, Reyhaneh Neghabat Shirazi, Alain Iost, and Denis Najjar. "Surface Cracking and Degradation of Dense Hydroxyapatite through Vickers Microindentation Testing." Applied Mechanics and Materials 66-68 (July 2011): 614–19. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.614.

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Surface degradation and cracking of dense hydroxyapatite were evaluated through Vickers micro indentation using indentation loads ranged from 25 gf to 2000 gf. Crack lengths, imprint diameters and the number of lateral cracks and chips were measured using SEM. The crack length-indentation load data were analyzed with regard to the specific relations of Palmqvist and fully developed radial cracks. Crack type transition load from Palmqvist to median crack was experimentally assessed through serial sectioning technique. The analytical estimated transition load, based on the theoretical relation of the indentation load and crack lengths showed a good agreement with one obtained from experimental itinerary. Palmqvist and median cracks were identified in low and medium indentation loads, respectively. High indentation load could also lead to the formation of lateral cracks and chips. The tendency for lateral cracking was evaluated taking into account the number of lateral cracks and chips. The chips were found to be appeared just after test in higher indentation load, whereas in medium loads they could be detectable only after several weeks.

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Yamamura, Keiko, Hisashi Iwata, and Toshihisa Yotsuyanagi. "Synthesis of antibiotic-loaded hydroxyapatite beads andin vitro drug release testing." Journal of Biomedical Materials Research 26, no. 8 (August 1992): 1053–64. http://dx.doi.org/10.1002/jbm.820260807.

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Calabrese, L., F. Fabiano, M. Currò, C. Borsellino, L. M. Bonaccorsi, V. Fabiano, R. Ientile, and E. Proverbio. "Hydroxyapatite Whiskers Based Resin Composite versus Commercial Dental Composites: Mechanical and Biocompatibility Characterization." Advances in Materials Science and Engineering 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/2172365.

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A systematic evaluation of mechanical and biocompatibility properties of different volume fractions of hydroxyapatite whiskers in comparison with three commercial dental composites filled with micro- and nanosilica particles was carried out. Six groups with different hydroxyapatite whiskers mass fractions were taken into account in order to be compared with the performances of silica particles based composites group. Flexural properties were evaluated via a universal testing machine (2.5 kN Zwick Line) with a 2 kN load-cell (sensitivity 0.001 N). The test was replicated 10 times for the seven experimental groups to better identify statically the significance of the mechanical performances data. MTT quantitative colorimetric assay was performed in order to evaluate the mitochondrial activity of living cells exposed to different resin composites. Data obtained show better interfacial interaction with filler/matrix until 20 wt% of hydroxyapatite whiskers partially replaced silica particles filler. After this threshold, the mechanical performances decrease dramatically due to both the hydroxyapatite agglomerates formation and the low degree of resin conversion. In addition, biocompatibility test showed less cytotoxic effect with the addition of 20 wt% of hydroxyapatite in comparison with higher rates.

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Zhu, Qing Xia, Wei Hui Jiang, Chuan Shao, and Yi Bao. "Thermophysical and Mechanical Properties of Carbonated Hydroxyapatite." Key Engineering Materials 512-515 (June 2012): 989–93. http://dx.doi.org/10.4028/www.scientific.net/kem.512-515.989.

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The carbonated hydroxyapatite (CHA) was synthesized by precipitation-calcination method. The influences of carbonate subsitution on high-temperature sintering, thermal expansion coefficient (CET) and flexural strength were investigated by the high-temperature dilatometer, scanning electron microscopy (SEM) and universal testing machine. The results showed that the sintering temperatures of CHA were related to the initial carbonate contents. The sintering temperature decreased with increasing initial carbonate contents. The CET of CHAs decreased with the increase of carbonate content, due to the stoma caused by the partially decompostion of CHAs. The CHA ceramics tested were as strong in flexure strength when compared to non-carbonated hydroxyapatite.

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Best, Serena, Shuo Zou, Roger A. Brooks, Jie Huang, Neil Rushton, and William Bonfield. "The Osteogenic Behaviour of Silicon Substituted Hydroxyapatite." Key Engineering Materials 361-363 (November 2007): 985–88. http://dx.doi.org/10.4028/www.scientific.net/kem.361-363.985.

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Dense and porous HA and Si-HA discs and granules with varying percentages of silicon substitution have been produced and physically and chemically characterised using scanning electron microscopy, surface area analysis, porosimetry, density measurement, image analysis, Xray diffraction, X-ray fluorescence, FT-infrared spectroscopy and in-vitro and in-vivo testing. Results have shown that cell adhesion in-vitro and bone apposition in-vivo are enhanced by the presence of silicon substitution in the hydroxyapatite structure. The biological response to the materials appears to indicate an optimum outcome for levels of silicon substitution of 0.8wt%.

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Srinivasan, D., R. Balasundaram, M. Ravichandran, G. Sakthi balan, S. Vijay, and S. Vishnu. "Wear behavior of hydroxyapatite reinforced polymer composite for biomedical applications." Surface Topography: Metrology and Properties 10, no. 1 (January 19, 2022): 015008. http://dx.doi.org/10.1088/2051-672x/ac4a43.

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Abstract In medical fields, hydroxyapatite (HA) is used for restoring the human bones and teeth. Nowadays, newer bio composites are being developed to replace the broken or removed teeth in human using hydroxyapatite. The original teeth may be removed from human, due to various reasons such as tooth decay, periodontal disease and gum diseases. Due to the bioactivity property of HA, it helps the tooth to grow. In this work, tribological properties of HA powder reinforced composite are investigated. Three most important factors that affect the properties of the composites were chosen and varied during wear testing of the composites. The HA powder weight %, applied load (P) and sliding distance (SD) were varied on the basis of Taguchi’s experimental design. Analysis of variance (ANOVA) and (Signal to Noise) SN ratio analysis was used to study the influence of each factor on the specific wear rate (SWR). It was concluded that the HA wt% highly influences the SWR of the composite during pin on disc testing.

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Li, Ai Min, Kang Ning Sun, and Run Hua Fan. "The Influence of Sintering Temperature on the Mechanical Properties and Microstructure of Carbon Nanotubes/Zirconia/Hydroxyapatite Biocomposites." Applied Mechanics and Materials 423-426 (September 2013): 38–42. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.38.

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Carbon nanotubes/zirconia/hydroxyapatite biocomposites was prepared by hot-pressing sintering under Ar atmosphere. The influence of sintering temperature on the mechanical properties and microstructure of carbon nanotube/zirconia/hydroxyapatite biocomposites was studied. We tested the bending strength and fracture toughness by universal electronic materials testing machine. The component of the composites was tested by XRD. The fracture surface of the composites was observed by SEM. The results indicate that the bending strength and fracture toughness of the composites is lower when the sintering temperature is lower than 1200°C. The difference of bending strength and fracture toughness at 1200°C and 1300°C is little. The number of them has risen markedly than the low temperature which reached to189.2MPa and 1.8MPa·m-1/2 respectively. The composition of the composites is mainly of hydroxyapatite, zirconia, carbon nanotubes, and a small amount of calcium phosphate, which indicated that part of the hydroxyapatite has decomposed. SEM photographs show that the fracture surface of the composites sintered at 1200 °C and 1300 °C is ductile fracture status and has bigger density.

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Witzler, Markus, Patrick Frank Ottensmeyer, Martin Gericke, Thomas Heinze, Edda Tobiasch, and Margit Schulze. "Non-Cytotoxic Agarose/Hydroxyapatite Composite Scaffolds for Drug Release." International Journal of Molecular Sciences 20, no. 14 (July 21, 2019): 3565. http://dx.doi.org/10.3390/ijms20143565.

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Healing of large bone defects requires implants or scaffolds that provide structural guidance for cell growth, differentiation, and vascularization. In the present work, an agarose-hydroxyapatite composite scaffold was developed that acts not only as a 3D matrix, but also as a release system. Hydroxyapatite (HA) was incorporated into the agarose gels in situ in various ratios by a simple procedure consisting of precipitation, cooling, washing, and drying. The resulting gels were characterized regarding composition, porosity, mechanical properties, and biocompatibility. A pure phase of carbonated HA was identified in the scaffolds, which had pore sizes of up to several hundred micrometers. Mechanical testing revealed elastic moduli of up to 2.8 MPa for lyophilized composites. MTT testing on Lw35human mesenchymal stem cells (hMSCs) and osteosarcoma MG-63 cells proved the biocompatibility of the scaffolds. Furthermore, scaffolds were loaded with model drug compounds for guided hMSC differentiation. Different release kinetic models were evaluated for adenosine 5′-triphosphate (ATP) and suramin, and data showed a sustained release behavior over four days.

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Das, Ashish, and Mukul Shukla. "Multifunctional hydroxyapatite and hopeite coatings on SS254 by laser rapid manufacturing for improved osseointegration and antibacterial character: A comparative study." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 234, no. 7 (May 18, 2020): 720–27. http://dx.doi.org/10.1177/0954411920917851.

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Orthopaedic metallic implant’s long-term success strongly depends upon the two main factors: osseointegration and antibacterial character. Bioceramic (hydroxyapatite and hopeite) coatings have been proven effective for getting strong osseointegration and antibacterial character. However, deterioration of bioceramic coatings during the implantation period can adversely affect its overall biological performance. To conquer this issue, this research work recommends an innovative process route of laser rapid manufacturing for depositing bioceramic (hydroxyapatite and hopeite) coatings with metallurgical bonding. Microstructure, phase composition, antibacterial efficacy and bioactivity were evaluated using scanning electron microscopy, X-ray diffraction, fluorescence-activated cell sorting technique and simulated body fluid immersion test. The promising results obtained from these characterizations and testing establish the new process route laser rapid manufacturing as an effective alternative to deposit multifunctional bioceramic (hydroxyapatite and hopeite) coatings on metallic prosthetic–orthopaedic implants.

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Rohmadi, Rohmadi, Widyanita Harwijayanti, Ubaidillah Ubaidillah, Joko Triyono, Kuncoro Diharjo, and Pamudji Utomo. "In Vitro Degradation and Cytotoxicity of Eggshell-Based Hydroxyapatite: A Systematic Review and Meta-Analysis." Polymers 13, no. 19 (September 23, 2021): 3223. http://dx.doi.org/10.3390/polym13193223.

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Objective: This review focuses on the in vitro degradation of eggshell-based hydroxyapatite for analyzing the weight loss of hydroxyapatite when applied in the human body. Cytotoxicity tests were used to observe cell growth and morphological effects. A systematic review and meta-analysis were conducted to observe the weight loss and viable cells of hydroxyapatite when used for implants. Method: Based on the Population, Intervention, Comparison, and Outcome (PICO) strategy, the articles used for literature review were published in English on SCOPUS, PubMed, and Google Scholar from 1 January 2012 to 22 May 2021. Data regarding existing experiments in the literature articles the in vitro degradation and cytotoxicity testing of eggshell-based hydroxyapatite determined the biocompatibility of the materials. A meta-analysis was conducted to calculate the mean difference between the solutions and soaking times used for degradation and the stem cells used for cytotoxicity. Results: From 231 relevant studies, 71 were chosen for full-text analysis, out of which 33 articles met the inclusion criteria for degradation and cytotoxicity analysis. A manual search of the field of study resulted in three additional articles. Thus, 36 articles were included in this systematic review. Significance: The aim of this study was to highlight the importance of the biocompatibility of eggshell-based hydroxyapatite. The weight loss and viability cells of eggshell-based hydroxyapatite showed optimum results for viable cells requirements above 70%, and there is a weight loss of eggshell-based hydroxyapatite for a material implant. The meta-analysis indicated significant differences in the weight loss of eggshell-based hydroxyapatite materials with different soaking times and solutions used. The various kinds of stem cells for incubation of cultured cells in contact with a device, either directly or through diffusions with various kinds of stem cells from animals and humans, yielded viability cells above 70%.

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Ghiara, Giorgia, Stefano Trasatti, Andrea Goglio, and Pierangela Cristiani. "Testing novel multicomposite materials for electromethanogenesis." E3S Web of Conferences 334 (2022): 08012. http://dx.doi.org/10.1051/e3sconf/202233408012.

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Electromethanogenesis is an innovative technology that uses a microbial electrochemical system to produce methane from CO2, in a power-to-gas (BEP2G) concept. The results of experimental tests of new and cost-effective carbonaceous materials for electrode are presented here. The study aims at optimizing electromethanogenesis processes at laboratory level in mesothermic condition. As part of the experiments, hydrogenotrophic microorganisms (Family Metanobacteriaceae of Archaea domains) were selected from a mixed consortium taken from a biogas digestate and inoculated in double-chamber bioelectrochemical systems. The maximum amount of methane produced was 0.3 - 0.8 mol/m2g (normalized to the cathode area) with carbon cloth electrodes. Aiming at improving the methane productivity, innovative materials for the electrodes were now studied, creating porous high-surface composites, and studying nitrogen carbons doped with Cu and hydroxyapatite (Multicomposite Cu@/HAP/C), as chemical catalysts for CO2 reduction (CO2RR). The description of the procedure for the Multicomposite Cu@/HAP/C production is reported in detail.

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Guimarães, Bruno, Susana I. L. Gomes, Elisabetta Campodoni, Monica Sandri, Simone Sprio, Magda Blosi, Anna L. Costa, Mónica J. B. Amorim, and Janeck J. Scott-Fordsmand. "Environmental Hazards of Nanobiomaterials (Hydroxyapatite-Based NMs)—A Case Study with Folsomia candida—Effects from Long Term Exposure." Toxics 10, no. 11 (November 18, 2022): 704. http://dx.doi.org/10.3390/toxics10110704.

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Hydroxyapatite (HA) is a calcium phosphate used in many fields, including biomedical applications. In particular, ion-doped HA nanomaterials (nHA) are developed for their increased bioactivity, particularly in the fields of regenerative medicine and nanomedicine. In this study, we assessed the ecotoxicological impact of five nHA materials: a synthesized calcium hydroxyapatite (CaP-HA), superparamagnetic iron-doped hydroxyapatite (Fe-HA), titanium-doped hydroxyapatite (Ti-HA), alginate/titanium-doped hydroxyapatite hybrid composite (Ti-HA-Alg), and a commercial HA. The soil ecotoxicology model species Folsomia candida (Collembola) was used, and besides the standard reproduction test (28 days), an extension to the standard for one more generation was performed (56 days). Assessed endpoints included the standard survival and reproduction, and additionally, growth. Exposure via the standard (28 days) did not cause toxicity, but reproduction increased in commercial HA (significantly at 320 mg HA/kg) whereas via the extension (56 days) it decreased in all tested concentrations. Juveniles’ size (56 days) was reduced in all tested nHA materials, except commercial HA. nHA materials seem to trigger a compromise between reproduction and growth. Long-term effects could not be predicted based on the standard shorter exposure; hence, the testing of at least two generations (56 days) is recommended to assess the toxicity of nanomaterials, particularly in F. candida. Further, we found that the inclusion of size as additional endpoint is highly relevant.

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Low, It Meng, Wei Kong Pang, and Ian J. Davies. "Mapping the Microstructure–Property Relationships in Cortical Bone." Key Engineering Materials 309-311 (May 2006): 523–26. http://dx.doi.org/10.4028/www.scientific.net/kem.309-311.523.

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Structure-property relationships in bovine cortical bone have been characterised using grazing-incidence synchrotron radiation diffraction, Vickers indentation and mechanical testing. Depth profiling results indicated the existence of distinct gradual changes in crystal disorder, phase abundance, and texture of hydroxyapatite whilst the crystallite size was depth-independent.

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Ding, Longjiang, Sili Han, Kun Wang, Sainan Zheng, Wenyue Zheng, Xiu Peng, Yumei Niu, Wei Li, and Linglin Zhang. "Remineralization of enamel caries by an amelogenin-derived peptide and fluoride in vitro." Regenerative Biomaterials 7, no. 3 (March 3, 2020): 283–92. http://dx.doi.org/10.1093/rb/rbaa003.

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Abstract Dental caries is one of the most common oral diseases in the world. This study was tantamount to investigate the combinatory effects of an amelogenin-derived peptide (called QP5) and fluoride on the remineralization of artificial enamel caries. The peptide QP5 was synthesized and characterized, and the binding capability of the peptide on hydroxyapatite (HA) and demineralized tooth enamel surface was analysed. Then, the mineralization function of the peptide and fluoride was studied through the spontaneous mineralization testing and remineralization on enamel caries in vitro. First, the novel peptide QP5 could bind on the hydroxyapatite and demineralized tooth enamel surfaces. Second, QP5 can transitorily stabilize the formation of amorphous calcium phosphate and direct the transformation into hydroxyapatite crystals alone and in combination with fluoride. In addition, compared to blocks treated by peptide QP5 alone or fluoride, the sample blocks showed significantly higher surface microhardness, lower mineral loss and shallower lesion depth after treatment with a combination of QP5 and fluoride at high or low concentrations. The peptide QP5 could control the crystallization of hydroxyapatite, and combinatory application of peptide QP5 and fluoride had a potential synergistic effect on the remineralization of enamel caries.

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Yang, X. B., X. Lu, J. J. Ge, and Jie Weng. "Effect of a Silane Coupling Agent on Mechanical Properties of Hydroxyapatite/Polycaprolactone Composites." Key Engineering Materials 361-363 (November 2007): 531–34. http://dx.doi.org/10.4028/www.scientific.net/kem.361-363.531.

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Silanization of hydroxyapatite was employed to improve the bonding between hydroxyapatite and polycaprolactone. FTIR of HA after silanization showed that new peaks attributed to silane do exist. The increase of melting and crystallization temperatures of silaned composites shown from DSC implied that there exists much stronger bonding between PCL and silaned HA particles. Fracture surface of composites after tensile testing observed by using SEM showed that silaned HA particles dispersed much evenly and coalesced compactly in PCL matrix, suggesting that silaned HA particles had good compatibility with PCL. The tensile strength and modulus increased from 16.81 MPa and 239.21 MPa to 20.49 MPa and 539.57 MPa, respectively.

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Meejoo, S., W. Pon-On, S. Charnchai, and T. Amornsakchai. "Substitution of Iron in Preparation of Enhanced Thermal Property and Bioactivity of Hydroxyapatite." Advanced Materials Research 55-57 (August 2008): 689–92. http://dx.doi.org/10.4028/www.scientific.net/amr.55-57.689.

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Incorporation of Iron into hydroxyapatite (HAp) has generated a novel material for which their properties differ from those of conventional HAp. Although XRD indicated that the as-prepared iron-substituted hydroxyapatite (HApFe) is of a single crystalline phase similar to that of HAp, we found that carbonate ions can incorporate in the HApFe structure 3 times better than in HAp. As results, HApFe possesses the Vickers microhardness about 1.5 times higher than that of HAp. Thermal behaviors and bioactivity of HApFe are discussed in comparison to those of HAp. Various experimental methods have been employed in this work including powder XRD, IR, SEM, DSC/TGA and Vickers Hardness testing.

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Yan, Ting Ting, Xiao Pei Wu, Yong Shun Cui, Qing Hua Chen, and Zhong Da Yang. "Porous Calcium Sulfate/Hydroxyapatite Whiskers Scaffold for Bone Tissue Engineering." Advanced Materials Research 738 (August 2013): 38–41. http://dx.doi.org/10.4028/www.scientific.net/amr.738.38.

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Porous calcium sulfate/hydroxyapatite whiskers composites scaffold is possible to be used in bone tissue engineering, for its biocompatibility, controllable degradation, and good mechanical properties. In this study, porous calcium sulfate/hydroxyapatite whisker composite scaffolds were fabricated by adding pore-forming agent and were characterized. The characteristics of the porous scaffolds were assessed by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and immersing testing techniques. It is shown that the scaffolds prepared in this article have the porous structure with the content of CaSO4 and HA. The scaffolds prepared in this article have been confirmed to be ideally used as biodegradable implants.

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Stevanovic, Milena, Marija Djosic, Ana Jankovic, Kyong Rhee, and Vesna Miskovic-Stankovic. "Electrophoretically deposited hydroxyapatite-based composite coatings loaded with silver and gentamicin as antibacterial agents." Journal of the Serbian Chemical Society 84, no. 11 (2019): 1287–304. http://dx.doi.org/10.2298/jsc190821092s.

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Increasing need for improved, compatible bone tissue implants led to the intensive research of novel biomaterials, especially hydroxyapatite (HAP)- -based composite materials on titanium and titanium alloy surfaces. Owing to its excellent biocompatibility and osteoinductivity properties, hydroxyapatite is often used as part of composite biomaterials aimed for orthopedic implant applications. In order to overcome persistent problems of bacterial infection, various antimicrobial agents and materials and their incorporation in such medical devices were investigated. This paper represents a comprehensive review of single-step electrodeposition on titanium of hydroxyapatite/chitosan/graphene composite coatings loaded with silver and antibiotic gentamicin as antibacterial agents. The improvement of mechanical and adhesive properties of deposited composite coatings was achieved by graphene and chitosan addition, while desirable antibacterial properties were introduced by including antibiotic gentamicin and silver. The biocompatibility of electrodeposited HAP and HAP-based composite coatings was evaluated by MTT testing, indicating a non-cytotoxic effect and high potential for future medical use as orthopedic implant coating.

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Sedghizadeh, Parish P., Philip Cherian, Sahar Roshandel, Natalia Tjokro, Casey Chen, Adam F. Junka, Eric Hu, et al. "Real-Time Impedance-Based Monitoring of the Growth and Inhibition of Osteomyelitis Biofilm Pathogen Staphylococcus aureus Treated with Novel Bisphosphonate-Fluoroquinolone Antimicrobial Conjugates." International Journal of Molecular Sciences 24, no. 3 (January 19, 2023): 1985. http://dx.doi.org/10.3390/ijms24031985.

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Osteomyelitis is a limb- and life-threatening orthopedic infection predominantly caused by Staphylococcus aureus biofilms. Bone infections are extremely challenging to treat clinically. Therefore, we have been designing, synthesizing, and testing novel antibiotic conjugates to target bone infections. This class of conjugates comprises bone-binding bisphosphonates as biochemical vectors for the delivery of antibiotic agents to bone minerals (hydroxyapatite). In the present study, we utilized a real-time impedance-based assay to study the growth of Staphylococcus aureus biofilms over time and to test the antimicrobial efficacy of our novel conjugates on the inhibition of biofilm growth in the presence and absence of hydroxyapatite. We tested early and newer generation quinolone antibiotics (ciprofloxacin, moxifloxacin, sitafloxacin, and nemonoxacin) and several bisphosphonate-conjugated versions of these antibiotics (bisphosphonate-carbamate-sitafloxacin (BCS), bisphosphonate-carbamate-nemonoxacin (BCN), etidronate-carbamate-ciprofloxacin (ECC), and etidronate-carbamate-moxifloxacin (ECX)) and found that they were able to inhibit Staphylococcus aureus biofilms in a dose-dependent manner. Among the conjugates, the greatest antimicrobial efficacy was observed for BCN with an MIC of 1.48 µg/mL. The conjugates demonstrated varying antimicrobial activity depending on the specific antibiotic used for conjugation, the type of bisphosphonate moiety, the chemical conjugation scheme, and the presence or absence of hydroxyapatite. The conjugates designed and tested in this study retained the bone-binding properties of the parent bisphosphonate moiety as confirmed using high-performance liquid chromatography. They also retained the antimicrobial activity of the parent antibiotic in the presence or absence of hydroxyapatite, albeit at lower levels due to the nature of their chemical modification. These findings will aid in the optimization and testing of this novel class of drugs for future applications to pharmacotherapy in osteomyelitis.

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Brostow, Witold, Miriam Estevez, Haley E. Hagg Lobland, Ly Hoang, J. Rogelio Rodriguez, and Susana Vargar. "Porous hydroxyapatite-based obturation materials for dentistry." Journal of Materials Research 23, no. 6 (June 2008): 1587–96. http://dx.doi.org/10.1557/jmr.2008.0191.

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New porous biomaterials based on hydroxyapatite (HAp) were designed as obturation materials for dental cavities. Synthetic HAp powder with a particle diameter of 150 μm was agglutinated using three different polyurethane monocomponents (rigid, semi-rigid, and flexible), enabling the matching of their properties to those of real teeth. Alumina particles were also added in some cases. Our new hybrid materials contain up to 60% HAp. Interconnected pores range in size from 100 to 350 μm, while the pore volume fraction varies between 25% and 60%. Most of these materials possess the right morphology for implants and prostheses because their porous structures can be vascularized for bone and tooth ingrowth. Some samples also contain alumina particles to improve the abrasion resistance and to support the stresses produced during mastication. The materials were characterized by x-ray diffraction, scanning electron microscopy, and mechanical testing, along with abrasion, scratch, sliding wear, friction, and staining tests.

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Yan, Han, Qianping Ran, Yong Yang, Xin Shu, Qian Zhang, Jiangang Zhang, and Jiaping Liu. "Investigation on the Effect of Hydroxyapatite Nanorod on Cement Hydration and Strength Development." Journal of Nanoscience and Nanotechnology 21, no. 3 (March 1, 2021): 1578–89. http://dx.doi.org/10.1166/jnn.2021.17387.

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This work investigated the effect of hydroxyapatite (HA) nanorods on the strength development and hydration of cement. Undispersed HA nanorods (HA-UD) and dispersed HA nanorods (HA-DN) were prepared by atom-efficient neutralization. The strength of mortars modified by HA nanorods was tested, as well as their compatibility with supplementary cementitious material. The hydration of HA-modified cement pastes was characterized via in situ X-ray diffraction, isothermal calorimetry and scanning electron microscopy. As the results suggest, the undispersed HA-DN caused a considerable increase in superplasticizer demand to achieve the same level of flow. Both HA nanorods showed a significant accelerating effect on early hydration, with approximately 100% strength enhancement at 12 h at 2.0% dosage. The effect on early strength of the nanorods is retained in systems with up to 30% fly ash in the binder mass. According to the characterizations, the rate of the hydration reaction in the acceleration period was enhanced by HA nanorods, and C3S consumption was also increased. In all of the testing situations, HA-DN showed superior performance, likely due to improved spatial distribution of the hydroxyapatites. The results suggest that proper dispersion of the nanorods is necessary to optimize its performance.

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Pujiyanto, E., A. E. Tontowi, Muhammad Waziz Wildan, and Widowati Siswomihardjo. "Porous Hydroxyapatite–Zirconia Composites Prepared by Powder Deposition and Pressureless Sintering." Advanced Materials Research 445 (January 2012): 463–68. http://dx.doi.org/10.4028/www.scientific.net/amr.445.463.

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In the present study, hydroxyapatite was synthesized from local gypsum by microwave-hydrothermal method. Different percentage amounts of zirconia (0, 20, 30 and 40 wt.%) and poly-methyl methacrylate (40, 50 and 60 wt.%) mixed with hydroxyapatite (HA) for six hours. These powder mixture were deposited using deposition machine to produce specimens. These specimens were sintered at a temperature of 140°C with holding time for 1 hour into the green parts. These green parts were sintered at temperature of 1450°C with holding time for 2 hours. This process produces porous hydroxyapatite-zirconia composites with porosity between 62.76-73.92 percent. These composites were examined by XRD, XRF, SEM-EDX, BET analysis and compressive strength testing. Compressive strength of porous hidroxyapatite-zirconia composite decreased from 3.706 to 0.039 MPa when percentage amounts of zirconia increased up to 40 wt.%. This caused by several factors i.e. increased porosity, grain zirconia cracked, zirconia reacted with HA to produce CaZrO3, β-TCP and α-TCP, HA matrix cracks because of the phase change of tetragonal-zirconia into monoclinic-zirconia.

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Sabet, AS, AH Jabbari, and M. Sedighi. "Microstructural properties and mechanical behavior of magnesium/hydroxyapatite biocomposite under static and high cycle fatigue loading." Journal of Composite Materials 52, no. 13 (September 21, 2017): 1711–22. http://dx.doi.org/10.1177/0021998317731822.

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In this study, magnesium/hydroxyapatite biocomposites having 2.5 and 5 wt% of hydroxyapatite have been fabricated using stir casting followed by hot extrusion method. Both microstructural and mechanical behaviors of these composites have been studied, which contain particle distribution, grain size, microhardness, tension, and compression tests. Then, high cycle fatigue tests were performed using a rotating-bending testing machine (under stress ratio of R = −1). The results indicate an acceptable particle distribution and grain refinement in the composites. Also, the microhardness of the composites has been increased in comparison with the pure extruded sample. The yield stress has been enhanced in both tension and compression tests by increasing the amount of reinforcement, while the maximum strain reduced. Moreover, the fabricated biocomposites revealed better overall high cycle fatigue life in comparison to pure Mg, and infinite life (>107 cycles) could be achieved in the composites. Scanning electron microscope images of the fracture surfaces showed that the agglomeration of hydroxyapatite particles is one of the most important criteria for crack initiation in the composites.

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Nakajima, Takayuki, Yasuchika Aoki, Atsuya Watanabe, Masahiro Inoue, Satoshi Yamaguchi, Junichi Nakamura, Yusuke Matsuura, Shigeo Hagiwara, Daisuke Himeno, and Seiji Ohtori. "Mechanical testing of cephalomedullary nail lag screws after the addition of hydroxyapatite substitutes." OTA International: The Open Access Journal of Orthopaedic Trauma 4, no. 4 (December 2021): e160. http://dx.doi.org/10.1097/oi9.0000000000000160.

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Naderi, S., M. A. Hassan, and A. R. Bushroa. "Alternative methods to determine the elastoplastic properties of sintered hydroxyapatite from nanoindentation testing." Materials & Design 67 (February 2015): 360–68. http://dx.doi.org/10.1016/j.matdes.2014.11.030.

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HAKOZAKI, Yuki, Yuichi OTSUKA, Yukio MIYASHITA, and Yoshiharu MUTOH. "914 Validation on testing methods of interfacial strength of plasma-sprayed hydroxyapatite coating." Proceedings of Conference of Hokuriku-Shinetsu Branch 2016.53 (2016): _914–1_—_914–5_. http://dx.doi.org/10.1299/jsmehs.2016.53._914-1_.

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SIDANE, Djahida, Hafit KHIREDDINE, and Sabeha YALA. "The hardness of the hydroxyapatite-titania bilayer coatings by microindentation and nanoindentation testing." Journal of Physics: Conference Series 939 (December 2017): 012027. http://dx.doi.org/10.1088/1742-6596/939/1/012027.

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47

Rusu, Laura Cristina, Ioan Avram Nedelcu, Mădălina Georgiana Albu, Maria Sonmez, Georgeta Voicu, Marius Radulescu, Denisa Ficai, Anton Ficai, Meda-Lavinia Negrutiu, and Cosmin Sinescu. "Tetracycline Loaded Collagen/Hydroxyapatite Composite Materials for Biomedical Applications." Journal of Nanomaterials 2015 (2015): 1–5. http://dx.doi.org/10.1155/2015/361969.

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The paper describes the preparation, characterisation, and testing of tetracycline loaded collagen-carboxymethylcellulose/hydroxyapatite ternary composite materials. The synthesis of this drug delivery system consists in two steps: the first step is the mineralization of collagen-carboxymethylcellulose gel while the second step corresponds to the loading of the ternary composite material with tetracycline. The obtained DDS is characterised by physicochemical, morphological, and release behaviour by using FTIR spectroscopy and microscopy, scanning electron microscopy, and UV-VIS spectroscopy. Based on the release study, it can be assumed that tetracycline is released in a prolonged way, assuring at least 6 days of antiseptic properties.

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Pathak, Dayanidhi Krishana, and Pulak Mohan Pandey. "An experimental investigation of the fabrication of biodegradable zinc–hydroxyapatite composite material using microwave sintering." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 14 (March 8, 2020): 2863–80. http://dx.doi.org/10.1177/0954406220910445.

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The present work focuses on the fabrication of zinc–hydroxyapatite biodegradable composite with the use of pressureless microwave sintering for the orthopedic load-bearing application. The samples were prepared using the powder metallurgy process. The powders of both materials were homogeneously mixed in the quantified proportions to form the uniform mixture. For the fabrication of samples, the planning of experiments was done with the central composite design. The effect of process factors such as the weight percentage of hydroxyapatite, compaction pressure, and microwave sintering factors such as sintering temperature, heating rate, and soaking time on the compressive yield strength and sintered density was evaluated. Cylindrical samples were prepared for compression testing. The experimental results exhibited the increase in the compressive yield strength as well as the sintered density with the decrease in the hydroxyapatite percentage and an increase in the compaction pressure. The results also revealed that the compressive yield strength and sintered density were found to be increased as the heating rate and sintering temperature increased. Sample characterization was carried out for phase determination and composition of the elements. The optimum process factors were obtained after the regression analysis, and the results of the optimum process factors were also verified with the confirmation experiments. The in vitro corrosion testing of the sample prepared with optimum factors was also carried out in the simulated body fluid at a temperature of 37 ± 0.5 ℃. The fabricated sample showed a good agreement between the mechanical and degradation properties as required for a human bone.

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Komala, Devi, Muhammad Nurul Amin, and Yani Corvianindya Rahayu. "Uji Sitotoksisitas Hidroksiapatit Cangkang Telur Ayam Ras (Gallus gallus) terhadap Sel Fibroblas Ligamen Periodontal Manusia." STOMATOGNATIC - Jurnal Kedokteran Gigi 19, no. 1 (March 31, 2022): 49. http://dx.doi.org/10.19184/stoma.v19i1.30702.

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Periodontitis is an inflammation disease of the periodontal tissues surrounding the teeth, include periodontal ligament fibroblast cell. The recently researches developed tissue engineering concept to accelerate regeneration and proliferation periodontal ligament cells. One of the major components of tissue engineering is scaffold. The hydroxyapatite is biomaterial that can be used as scaffold. The egg shell has the potential biowaste to be a source of hydroxyapatite biomaterial. Before being applied as a scaffold in the medical field, cytotoxicity testing needs to be done. This study aimed to examine toxicity effect of egg shell hydroxyapatite in various concentration toward human periodontal ligament fibroblast cells. This study used human periodontal ligament fibroblast primary cells (5x103) in microplate 96 wells which divided into 7 groups, control cells, control media without cells and the treatment groups with concentration egg shell hydroxyapatite100 μg/ml, 75 μg/ml, 50 μg/ml, 25 μg/ml dan 25 μg/ml and incubated for 24 hours. Cytotoxicity test was conducted using MTT assay. Optical density values describe the viability of living cells and the readings were done using ELISA readers, subsequently the data were analyzed using One way ANOVA. The number of human periodontal ligament cells at all concentration showed that the percentage of cell life is more than 90%. Egg shell hydroxyapatite at all concentrations tested is not toxic toward human periodontal ligament fibroblas cells.

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Goldberg, Margarita, Valeriy Smirnov, Sergey Kucev, Natalia Sergeeva, Irina Sviridova, Valentina Kirsanova, Syraia Akhmedova, and Sergey Barinov. "Nanoceramics Composite Biomaterials in the Calcium Carbonate-Hydroxyapatite System." Advanced Materials Research 123-125 (August 2010): 339–42. http://dx.doi.org/10.4028/www.scientific.net/amr.123-125.339.

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Abstract:

Composite powders in the calcium carbonate (CC) – hydroxyapatite (HA) system with carbonate content up to 50 wt. % were synthesized by the precipitation from aqueous solution and characterized in detail. Specific area of the powders decreases with an increase in carbonate content due to appearance of large elongated CC crystals of about 0,5 micrometer size. The use of highly active to sintering nanodisperse powders resulted in lowering of sintering temperature below 7200C, preventing thermal decomposition. Ceramics of about 20 wt.% carbonate content revealed the highest strength of about 77 MPa, having the grain size of about 100 nm. According to in vitro testing, the materials are non toxic for human fibroblast cells.

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Journal articles on the topic 'Hydroxyapatite Testing'

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