Displaying publications 1 - 20 of 30 in total

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  1. An in vivo study of a locally-manufactured hydroxyapatite-based material as bone replacement material
    Abdul Razak NH, Al-Salihi KA, Samsudin AR
    Med J Malaysia, 2004 May;59 Suppl B:119-20.
    PMID: 15468847
    Defects were created in the mandible of a rabbit model whereby the right side was implanted with hydroxyapatite (HA) while the left side was left empty to act as control. Both the implant and control sites were evaluated clinically and histologically at 4,12,20,22 weeks. Decalcified sections were studied under confocal laser scanning microscope. No reactive cells were evident microscopically in all sections. There was bone ingrowth as early as 4 weeks when viewed by the topographic method. Enhancement of osteoconduction was evident by the presence of abundant capillaries, perivascular tissue and osteoprogenitor cells of the host. At 22 weeks, the implanted defect showed mature bone formation filling almost the whole field. This study demonstrated that the dense HA exhibits excellent biocompatibility as noted by the complete absence of reactive cells. It also promotes osteoconduction.
    Matched MeSH terms: Hydroxyapatites*
  2. Gene expressions screening of human cell line exposed to locally produced biomaterial
    Azlina A, Samsudin AR
    Med J Malaysia, 2004 May;59 Suppl B:166-7.
    PMID: 15468870
    In Malaysia, the field of genomics in toxicology is still in infancy. The purpose of this study is to focus on the use of toxicogenomics for determination of gene expressions changes in cultured human fibroblast cells treated with genotoxicology free biomaterial (using Ames test), a locally produced hyroxyapatite. Dose and time response is similar to Ames test with time interval up to 21 days. mRNA is extracted, followed with RT-PCR and polyacrilamide gel electrophoresis. Changes of the gene expressions compared to the non-treated fibroblast mRNA would suggest some gene interactions in the molecule level associated with the exposure of the fibroblast cell line to the biomaterials. Further analysis (cloning & sequencing) shall be carried out to investigate the genes involved as simple changes might not signified toxicity.
    Matched MeSH terms: Hydroxyapatites/toxicity*
  3. Biocompatible magnesium-doped biphasic calcium phosphate for bone regeneration
    Ballouze R, Marahat MH, Mohamad S, Saidin NA, Kasim SR, Ooi JP
    J Biomed Mater Res B Appl Biomater, 2021 Oct;109(10):1426-1435.
    PMID: 33484103 DOI: 10.1002/jbm.b.34802
    Autologous bone grafting remains the gold standard for almost all bone void-filling orthopedic surgery. However, autologous bone grafting has several limitations, thus scientists are trying to identify an ideal synthetic material as an alternative bone graft substitute. Magnesium-doped biphasic calcium phosphate (Mg-BCP) has recently been in the spotlight and is considered to be a potential bone substitute. The Mg-BCP is a mixture of two bioceramics, that is, hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), doped with Mg2+ , and can be synthesized through chemical wet-precipitation, sol-gel, single diffusion gel, and solid state reactions. Regardless of the synthesis routes, it is found that the Mg2+ preferentially accommodates in β-TCP lattice instead of the HA lattice. The addition of Mg2+ to BCP leads to desirable physicochemical properties and is found to enhance the apatite-forming ability as compared to pristine BCP. In vitro results suggest that the Mg-BCP is bioactive and not toxic to cells. Implantation of Mg-BCP in in vivo models further affirmed its biocompatibility and efficacy as a bone substitute. However, like the other bioceramics, the optimum physicochemical properties of the Mg-BCP scaffold have yet to be determined. Further investigations are required regarding Mg-BCP applications in bone tissue engineering.
    Matched MeSH terms: Hydroxyapatites/chemistry*
  4. Characterization of nickel-doped biphasic calcium phosphate/graphene nanoplatelet composites for biomedical application
    Baradaran S, Moghaddam E, Nasiri-Tabrizi B, Basirun WJ, Mehrali M, Sookhakian M, et al.
    Mater Sci Eng C Mater Biol Appl, 2015 Apr;49:656-668.
    PMID: 25686995 DOI: 10.1016/j.msec.2015.01.050
    The effect of the addition of an ionic dopant to calcium phosphates for biomedical applications requires specific research due to the essential roles played in such processes. In the present study, the mechanical and biological properties of Ni-doped hydroxyapatite (HA) and Ni-doped HA mixed with graphene nanoplatelets (GNPs) were evaluated. Ni (3wt.% and 6wt.%)-doped HA was synthesized using a continuous precipitation method and calcined at 900°C for 1h. The GNP (0.5-2wt.%)-reinforced 6% Ni-doped HA (Ni6) composite was prepared using rotary ball milling for 15h. The sintering process was performed using hot isostatic pressing at processing conditions of 1150°C and 160MPa with a 1-h holding time. The results indicated that the phase compositions and structural features of the products were noticeably affected by the Ni and GNPs. The mechanical properties of Ni6 and 1.5Ni6 were increased by 55% and 75% in hardness, 59% and 163% in fracture toughness and 120% and 85% in elastic modulus compared with monolithic HA, respectively. The in-vitro biological behavior was investigated using h-FOB osteoblast cells in 1, 3 and 5days of culture. Based on the osteoblast results, the cytotoxicity of the products was indeed affected by the Ni doping. In addition, the effect of GNPs on the growth and proliferation of osteoblast cells was investigated in Ni6 composites containing different ratios of GNPs, where 1.5wt.% was the optimum value.
    Matched MeSH terms: Hydroxyapatites/chemistry
  5. Dielectric and material analysis on physicochemical activity of porous hydroxyapatite/cornstarch composites
    Beh CY, Cheng EM, Mohd Nasir NF, Eng SK, Abdul Majid MS, Ridzuan MJM, et al.
    Int J Biol Macromol, 2021 Jan 01;166:1543-1553.
    PMID: 33181217 DOI: 10.1016/j.ijbiomac.2020.11.034
    This paper provides a comprehensive analysis of the dielectric and physicochemical properties of the porous hydroxyapatite/cornstarch (HAp/Cs) composites in a new perspective. The porous composites have been characterized via SEM, FTIR, XRD and dielectric spectroscopy. The dielectric permittivity spectra were obtained in Ku-band (12.4-18.0 GHz) and it was correlated with the physicochemical properties of the porous HAp/Cs. Porous HAp/Cs composites exhibits low ε' and negative ε″, which influenced by the microstructural morphology, interaction between Hap and Cs, as well as crystalline features due to the various proportion of the HAp/Cs. The physicochemical effect of the composites results in the dielectric polarization and energy loss. This phenomenon indicates the presence of the three obvious relaxation responses in the ε' spectrum (13.2-14.0, 15.2-16.0, and 16.6-17.4 GHz) and the negative behaviours in the ε″ spectrum. The relationships between physicochemical and dielectric properties of the porous composite facilitate the development of the non-destructive microwave evaluation test for the porous composite.
    Matched MeSH terms: Hydroxyapatites/chemistry*
  6. A "healthy apatite" for bone repair
    Best SM, Patel N, Porter AE, Bonfield W
    Med J Malaysia, 2004 May;59 Suppl B:129-30.
    PMID: 15468852
    Bone is unique in its ability to adapt structure to functional requirements, but as is all too obvious in an ever-ageing population it is susceptible to a number of degenerative diseases. Therefore there is an increasing need for materials for bone replacement. Clearly, the ideal material with which to replace bone, would be bone itself, but the major problem now facing us is that there is an insufficient supply of the natural bone to satisfy the clinical requirements. Hence, there is a need for the development of chemically synthesised bone graft substitutes
    Matched MeSH terms: Hydroxyapatites*
  7. Fulltext Effects of sintering time on the physical and compositional properties of porous biphasic calcium phosphate foam
    Cik Rohaida, C.H., Idris, B., Rusnah, M., Mohd Reusmaazran, Y., Narimah, A.B.
    Journal of Nuclear and Related Technologies, 2009;2009(1):206-216.
    MyJurnal
    Phase composition of calcium phosphate ceramic is a characteristic directly related to the biological response of implants due to the differences in mechanical and biochemical properties of these compounds. The biodegradation rate of biphasic calcium phosphate (BCP) can be controlled by altering the HA to β-TCP ratios. In this study the crystalline phase evolution of BCP synthesized via precipitation from aqueous solution of (NH4)2PO4 titrated into heated solution of Ca (NO3)2 was evaluated. The resulting powder was fabricated into porous scaffold using polyurethane foam method. Bulk powders were sintered from 700 - 1400°C to determine the most significant sintering temperature to obtain a stable and well crystallize BCP phases. The porous scaffolds were then sintered at selected temperature and the effects of various sintering times from 5,7,9,11,13 and 15 h were investigated. Bulk powders were characterized by dilatometer, IR analysis and XRD and porous scaffolds were analyzed by XRD and SEMEdx. RIR method was performed to show that the HA to β-TCP ratios were increased with increasing of sintering time and reached the maximum HA value at 11h. It is found that, the possibilities to manipulate the HA to β-TCP ratios in BCP porous scaffold by just controlling the sintering time of the scaffold without controlling the starting powder characteristics.
    Matched MeSH terms: Hydroxyapatites
  8. Development of a bioactive dentin adhesive resin modified with magnesium-doped synthetic hydroxyapatite crystals
    Daood U, Fawzy A
    J Mech Behav Biomed Mater, 2023 Apr;140:105737.
    PMID: 36827934 DOI: 10.1016/j.jmbbm.2023.105737
    The aim is to evaluate the development of an experimental multi-mode/Universal resin-based dentin adhesive modified with synthetic Mg2+ doped hydroxyapatite crystals (HAp) having self-remineralization and antibiofilm properties. HAp doped with Mg2+ was prepared by the precipitation method. Experimental adhesives were subjected to degree of conversion and X-ray diffraction test for size and crystal structure. Bond strength was tested, and electron microscopy (SEM/TEM) imaging of resin-dentin interface was done along with nanoleakage, nanoindentation, confocal and Raman analyses. S. mutans was analysed using CLSM images against modified adhesive specimens. Nucleating abilities within the resin-dentin specimens are determined by measuring Ca2+. Alkaline phosphatase, Runx2, and Ocn transcripts are amplified using quantitative polymerase chain reaction (q-PCR). A calcium assay is performed to quantify level of mineralisation. When compared to control adhesives, the 0.5% Hap/Mg2+ containing experimental dentin adhesive demonstrated improved interaction with dentin. The preservation of uniform intact hybrid layer with the absence of nanoleakage indicated dentin bond integrity with 0.5% HAP/Mg2+ modified adhesive. Self-remineralization and antibiofilm potentials are supported.
    Matched MeSH terms: Hydroxyapatites
  9. Fulltext Fabrication of Hydroxyapatite with Bioglass Nanocomposite for Human Wharton's-Jelly-Derived Mesenchymal Stem Cell Growing Substrate
    Ebrahimi S, Hanim YU, Sipaut CS, Jan NBA, Arshad SE, How SE
    Int J Mol Sci, 2021 Sep 06;22(17).
    PMID: 34502544 DOI: 10.3390/ijms22179637
    Recently, composite scaffolding has found many applications in hard tissue engineering due to a number of desirable features. In this present study, hydroxyapatite/bioglass (HAp/BG) nanocomposite scaffolds were prepared in different ratios using a hydrothermal approach. The aim of this research was to evaluate the adhesion, growth, viability, and osteoblast differentiation behavior of human Wharton's-jelly-derived mesenchymal stem cells (hWJMSCs) on HAp/BG in vitro as a scaffold for application in bone tissue engineering. Particle size and morphology were investigated by TEM and bioactivity was assessed and proven using SEM analysis with hWJMSCs in contact with the HAp/BG nanocomposite. Viability was evaluated using PrestoBlueTM assay and early osteoblast differentiation and mineralization behaviors were investigated by ALP activity and EDX analysis simultaneously. TEM results showed that the prepared HAp/BG nanocomposite had dimensions of less than 40 nm. The morphology of hWJMSCs showed a fibroblast-like shape, with a clear filopodia structure. The viability of hWJMSCs was highest for the HAp/BG nanocomposite with a 70:30 ratio of HAp to BG (HAp70/BG30). The in vitro biological results confirmed that HAp/BG composite was not cytotoxic. It was also observed that the biological performance of HAp70/BG30 was higher than HAp scaffold alone. In summary, HAp/BG scaffold combined with mesenchymal stem cells showed significant potential for bone repair applications in tissue engineering.
    Matched MeSH terms: Hydroxyapatites/chemistry*
  10. Effect of space holders on fabrication of porous titanium alloy-hydroxyapatite composite through powder injection molding
    Farrahshaida Mohd Salleh, Abu Bakar Sulong, Muhammad Rafi Raza, Norhamidi Muhamad, Lim TF
    Sains Malaysiana, 2017;46:1651-1657.
    owder injection molding (PIM) is able to produce porous titanium alloy/hydroxyapatite composite through the space holder technique. Thermal debinding and sintering processes were the main challenges due to different properties of metal and ceramic in producing such composite. This study focused on the effect of different space holders on the physical and mechanical properties of debound and sintered porous titanium aloi/hydroxyapatite composite. The feedstock is containing of 80 wt. % of titanium alloy/hydroxyapatite with 20 wt. % of space holders such as sodium chloride (NaCl) and polymethylmethacrylate (PMMA), respectively. The binders were then removed from the injected samples by two stages of debinding; solvent and thermal debinding. The sintering was performed at three different temperatures 1100oC, 1200oC and 1300oC at a heating rate of 10oC /min and holding time of 5 h. It was found that the samples containing PMMA space holder was fractured after sintering. While, the samples containing NaCl space holder successfully formed pores and not fractured. At sintering temperature of 1300oC, the density, compressive strength and porosity volume percentages for the sintered sample containing NaCl space holder were 3.05 g/cm3, 91.7 MPa. and 11.9 vol%, respectively.
    Matched MeSH terms: Hydroxyapatites
  11. In-vitro evaluation of microleakage of bioceramic root-end filling materials: A spectrophotometric study
    Gupta R, Kewalramani R
    J Oral Biol Craniofac Res, 2021 03 10;11(2):330-333.
    PMID: 33786296 DOI: 10.1016/j.jobcr.2021.03.001
    Aim: To evaluate the microleakage of newer bioceramic root-end filling materials.

    Material and method: Sixty freshly extracted human single-rooted mandibular premolar teeth were selected for the study. Teeth with fractured root, cracks, anddilacerations were rejected. All teeth were cleaned with ultrasonic scalers. Standard access opening was done and root canal treatment was performed with rotary files followed by obturation. After storing in saline for a week apical 3 ​mm of the root was resected at 900 angles to the long axis of the root. Retro cavity preparation was done with ultrasonic tips. The teeth were divided into four groups of 15 specimens each. Group I - Biodentin, GroupII-Bioaggregate, Group III - MTA Plus, and Group IV - MTA. After the restoration of retro cavities of all the teeth as per manufacture instructions, two coats of nail varnish were applied to leave apical 3 ​mm. All teeth were stored in 2% methylene blue for 72 ​h followed by emersion in 65% nitric acid for the next 72 ​h for Dye extraction. The obtained supernatant solution was then centrifuged and optical density or absorbance was measured with a UV spectrophotometer.

    Result: Microleakage was found to be increasing in this order: Biodentin ​ ​0.01).

    Conclusion: All materials exhibit some amount of microleakage. Biodentin shows the least microleakage among all the bioceramic material groups. Hence, Biodentin and bioaggregate are better material of choice for the retrograde filling to prevent microleakage.

    Matched MeSH terms: Hydroxyapatites
  12. Comparison of hydroxyapatite powders derived from different resources
    Hee SL, Nik Intan NI, Fazan F
    Med J Malaysia, 2004 May;59 Suppl B:77-8.
    PMID: 15468827
    There is a great demand of Hydroxyapatite (HA) material in Orthopaedics and Dental applications due to its similarity to human bone. However, the lack of availability and due to high import cost of this material in Malaysia, research in producing synthetic HA locally is therefore timely. The use of local resources as the raw materials for the production of HA is also desirable in reducing the overall cost of HA. In this study, two HA materials were synthesised from different starting precursors, i.e. commercial pure Ca(OH)2 (HAS) and Ca(OH)2 directly from a local natural limestone deposit (HAL). Whereas a commercially available HA "Captal 60" (HAC) was used as reference. The synthesised powders obtained were fired at 1000 degrees C and at 1250 degrees C. Characterisation evaluations on bulk properties were carried out using XRD, SEM-EDX, ICP and FTIR. The results indicate that both HAS and HAL are comparable to HAC even at 1000 degrees C. Thus, the local natural limestone can be used to form HA. However, the overall appearance of these materials are quite different (HAC - blue, HAS - greenish and HAL - light green). The reasons for this and the subsequent mechanical and bioactive effects of these materials are currently being investigated.
    Matched MeSH terms: Hydroxyapatites/analysis; Hydroxyapatites/chemical synthesis*
  13. Fulltext Bioactivity studies and adhesion of human osteoblast (hFOB) on silicon-biphasic calcium phosphate material
    Ibrahim S, Sabudin S, Sahid S, Marzuke MA, Hussin ZH, Kader Bashah NS, et al.
    Saudi J Biol Sci, 2016 Jan;23(1):S56-63.
    PMID: 26858566 DOI: 10.1016/j.sjbs.2015.10.024
    Surface reactivity of bioactive ceramics contributes in accelerating bone healing by anchoring osteoblast cells and the connection of the surrounding bone tissues. The presence of silicon (Si) in many biocompatible and bioactive materials has been shown to improve osteoblast cell adhesion, proliferation and bone regeneration due to its role in the mineralisation process around implants. In this study, the effects of Si-biphasic calcium phosphate (Si-BCP) on bioactivity and adhesion of human osteoblast (hFOB) as an in vitro model have been investigated. Si-BCP was synthesised using calcium hydroxide (Ca(OH)2) and phosphoric acid (H3PO4) via wet synthesis technique at Ca/P ratio 1.60 of material precursors. SiO2 at 3 wt% based on total precursors was added into apatite slurry before proceeding with the spray drying process. Apatite powder derived from the spray drying process was pressed into discs with Ø 10 mm. Finally, the discs were sintered at atmospheric condition to obtain biphasic hydroxyapatite (HA) and tricalcium phosphate (TCP) peaks simultaneously and examined by XRD, AFM and SEM for its bioactivity evaluation. In vitro cell viability of L929 fibroblast and adhesion of hFOB cell were investigated via AlamarBlue® (AB) assay and SEM respectively. All results were compared with BCP without Si substitution. Results showed that the presence of Si affected the material's surface and morphology, cell proliferation and cell adhesion. AFM and SEM of Si-BCP revealed a rougher surface compared to BCP. Bioactivity in simulated body fluid (SBF) was characterised by pH, weight gain and apatite mineralisation on the sample surface whereby the changes in surface morphology were evaluated using SEM. Immersion in SBF up to 21 days indicated significant changes in pH, weight gain and apatite formation. Cell viability has demonstrated no cytotoxic effect and denoted that Si-BCP promoted good initial cell adhesion and proliferation. These results suggest that Si-BCP's surface roughness (164 nm) was significantly higher than BCP (88 nm), thus enhancing the adhesion and proliferation of the osteoblast.
    Matched MeSH terms: Hydroxyapatites
  14. Chromosome aberration test for hydroxyapatite in sheep
    Kannan TP, Nik Ahmad Shah NL, Azlina A, Samsudin AR, Narazah MY, Salleh M
    Med J Malaysia, 2004 May;59 Suppl B:168-9.
    PMID: 15468871
    The present study is aimed at finding the mutagenicity and cytotoxicity of dense form of synthetic hydroxyapatite (Source: School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia) in the blood of sheep. The biomaterial was implanted in the tibia of Malin, an indigenous sheep breed of Malaysia. Blood was collected from the sheep before implantation of the biomaterial, cultured and a karyological study was made. Six weeks after implantation, blood was collected from the same animal, cultured and screened for chromosome aberrations. The mitotic indices and karyological analysis indicated that the implantation of synthetic hydroxyapatite (dense form) did not produce any cytotoxicity or chromosome aberrations in the blood of sheep.
    Matched MeSH terms: Hydroxyapatites/toxicity*
  15. Histological evaluation of the early bone response to hydroxyapatite (HA) implanted in rabbit tibia
    Khadijah K, Mashita M, Saidu MF, Fazilah F, Khalid KA
    Med J Malaysia, 2004 May;59 Suppl B:123-4.
    PMID: 15468849
    This study is to qualitatively evaluate a locally produced hydroxyapatite (HA), made by AMREC-SIRIM in an experimental animal bone defect using New Zealand White (NZW) rabbits. HA cylindrical blocks measuring 2.5 mm (D) x 1.0 mm (H) were implanted in the rabbits' left tibia. The tibias were harvested within one to three weeks post-implantation. The implantion site was cut into thin undecalcified sections of about 30 microm to 60 microm and stained with Toluidine Blue and Goldner's Masson Trichrome. Microscopic examinations using standard light microscopy of these slides were performed.
    Matched MeSH terms: Hydroxyapatites*
  16. Fulltext In-vitro evaluation of the effectiveness of polyphenols based strawberry extracts for dental bleaching
    Kohli S, Bhatia S, Banavar SR, Al-Haddad A, Kandasamy M, Qasim SSB, et al.
    Sci Rep, 2023 Mar 13;13(1):4181.
    PMID: 36914760 DOI: 10.1038/s41598-023-31125-6
    To formulate a dental bleaching agent with strawberry extract that has potent bleaching properties and antimicrobial efficacy. Enamel specimens (3 × 3 × 2 mm3) were prepared. Quaternary Ammonium Silane (CaC2 enriched) was homogenized with fresh strawberries: Group 1: supernatant strawberry (10 g) extract 
    Matched MeSH terms: Hydroxyapatites
  17. Synthesis and characterization of strontium-doped hydroxyapatite powder via sol-gel method
    Mardziah CM, Sopyan I, Hamdi M, Ramesh S
    Med J Malaysia, 2008 Jul;63 Suppl A:79-80.
    PMID: 19024993
    Improvement of the mechanical properties of hydroxyapatite (HA) can be achieved by the incorporation of metal. In addition, incorporation of strontium ion into HA crystal structures has been proved effective to enhance biochemical properties of bone implant. In this research, strontium-doped HA powder was developed via a sol-gel method to produce extraordinarily fine strontium-doped HA (Sr-doped HA) powder. XRD measurement had shown that the powder contained hydroxyapatite phase only for all doping concentration except for 2%, showing that Sr atoms have suppressed the appearance of beta-TCP as the secondary phase. Morphological evaluation by FESEM measurement shows that the particles of the Sr-doped HA agglomerates are globular in shape with an average size of 1-2 microm in diameter while the primary particles have a diameter of 30-150 nm in average.
    Matched MeSH terms: Hydroxyapatites/chemistry*
  18. A comparative study of osseointegration phenomenon in coated and non-coated NiTi implants in a rabbit model
    Najafpour HD, Suzina AH, Nizam A, Samsudin AR
    Med J Malaysia, 2004 May;59 Suppl B:121-2.
    PMID: 15468848
    There was a significant increased in Absolute Contact Length measurements of endosteal bone growth along the Nickel-Titanium (NiTi) implant coated with the natural coral powder and Hydroxyapatite (HA) compared to the non-calcium coated implants. This study demonstrated that coated implants seemed to show earlier and higher osseointergration phenomena compared to non coated ones. Furthermore, there was significantly greater bone-to-implant contact at the apical 1/3rd of the coated implants.
    Matched MeSH terms: Hydroxyapatites*
  19. DNA damage evaluation of hydroxyapatite on fibroblast cell L929 using the single cell gel electrophoresis assay
    Rajab NF, Yaakob TA, Ong BY, Hamid M, Ali AM, Annuar BO, et al.
    Med J Malaysia, 2004 May;59 Suppl B:170-1.
    PMID: 15468872
    Hydroxyapatite is the main component of the bone which is a potential biomaterial substance that can be applied in orthopaedics. In this study, the biocompatibility of this biomaterial was assessed using an in vitro technique. The cytotoxicity and genotoxicity effect of HA2 and HA3 against L929 fibroblast cell was evaluated using the MTT Assay and Alkaline Comet Assay respectively. Both HA2 and HA3 compound showed low cytotoxicity effect as determined using MTT Assay. Cells viability following 72 hours incubation at maximum concentration of both HA2 and HA3 (200 mg/ml) were 75.3 +/- 8.8% and 86.7 +/- 13.1% respectively. However, the cytotoxicity effect of ZnSO4.7H2O as a positive control showed an IC50 values of 46 mg/ml (160 microM). On the other hand, both HA2 and HA3 compound showed a slight genotoxicity effect as determined using the Alkaline Comet Assay following incubation at the concentration 200 mg/ml for 72 hours. This assay has been widely used in genetic toxicology to detect DNA strand breaks and alkali-labile site. The percentage of the cells with DNA damage for both substance was 27.7 +/- 1.3% and 15.6 +/- 1.0% for HA2 and HA3 respectively. Incubation of the cells for 24 hours with 38 microg/ml (IC25) of positive control showed an increase in percentage of cells with DNA damage (67.5 +/- 0.7%). In conclusion, our study indicated that both hydroxyapatite compounds showed a good biocompatibility in fibroblast cells.
    Matched MeSH terms: Hydroxyapatites/toxicity*
  20. The influence of sintering temperature on the porosity and strength of porous hydroxyapatite ceramics
    Rusnah M, Andanastuti M, Idris B
    Med J Malaysia, 2004 May;59 Suppl B:158-9.
    PMID: 15468866
    The present paper reports on the influence of sintering temperature on the porosity and strength of porous hydroxyapatite (HA). HA powder was first prepared by the sol-gel precipitation method using calcium hydroxide and ortho-phosporic acid. The fine HA powder, measuring <50 microm was then mixed into a slurry with the addition of binder agent, being a mixture of sago and PVA. A small amount of sodium dodecyl sulphate was also used as a foaming agent. Porous HA samples were then prepared via slip casting technique. The surface morphology of the sintered samples was observed under scanning electron microscopy at 20 kV and the compositions were determined via SEM-EDX. A universal testing machine was used to determine the compaction strength of the sintered samples.
    Matched MeSH terms: Hydroxyapatites/analysis*
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