Displaying publications 21 - 40 of 52 in total

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  1. Fulltext Influence of CO2 flux on the properties of carbonate apatite synthesized by solid state reaction
    Jamuna, K., Noorsal, K., Zakaria, F.A., Hussin, Z.H.
    ASM Science Journal, 2010;4(1):41-47.
    MyJurnal
    Introducing CO2 flux as the carbonate source had an effect on the carbonate content of carbonate apatite (CAp) synthesized by solid state reaction. The reactants were CaCO3 and beta-tricalcium phosphate (β-TCP) and the heat treatment in air was performed at 1250ºC followed by instant cooling in CO2 flux for temperatures ranging from 800ºC room temperature (RT) . The influence of CO2 flux at various temperature drop differences in the cooling process (1250ºC RT, 1250ºC–500ºC, 1250ºC–600ºC, 1250ºC–700ºC, and 1250ºC–800ºC) was tested to optimize the carbonation degree and subsequent effects on the physical and mechanical properties of CAp. Thermally treated samples revealed an increasing degree of carbonation, achieving a maximum of 5.2 wt% at the highest (1250ºC RT) and a minimum of 2.7 wt% at the lowest (1250ºC–800ºC) temperature drop differences, respectively. This showed that the carbonate content was correlated with the increase in exposure to CO2 flux. However, consistent compressive strength, tensile strength, density and porosity were observed against increasing temperature drop differences which indicated that the degree of carbonation exerted no influence on the physical and mechanical properties of CAp. This method enabled the synthesis of solid state CAp simply by exposing calcium phosphate mixtures to CO2 flux. It also allowed the control of carbonate content for desired medical applications.
    Matched MeSH terms: Calcium Phosphates
  2. Intramedullary cement osteosynthesis (IMCO): a pilot study in sheep
    Mirzasadeghi A, Narayanan SS, Ng MH, Sanaei R, Cheng CH, Bajuri MY, et al.
    Biomed Mater Eng, 2014;24(6):2177-86.
    PMID: 25226916 DOI: 10.3233/BME-141029
    The application of bone substitutes and cements has a long standing history in augmenting fractures as a complement to routine fracture fixation techniques. Nevertheless, such use is almost always in conjunction with definite means of fracture fixation such as intramedullary pins or bone plates. The idea of using biomaterials as the primary fixation bears the possibility of simultaneous fixation and bone enhancement. Intramedullary recruitment of bone cements is suggested in this study to achieve this goal. However, as the method needs primary testings in animal models before human implementation, and since the degree of ambulation is not predictable in animals, this pilot study only evaluates the outcomes regarding the feasibility and safety of this method in the presence of primary bone fixators. A number of two sheep were used in this study. Tibial transverse osteotomies were performed in both animals followed by external skeletal fixation. The medullary canals, which have already been prepared by removing the marrow through proximal and distal drill holes, were then injected with calcium phosphate cement (CPC). The outcomes were evaluated postoperatively by standard survey radiographs, morphology, histology and biomechanical testings. Healing processes appeared uncomplicated until week four where one bone fracture recurred due to external fixator failure. The results showed 56% and 48% cortical thickening, compared to the opposite site, in the fracture site and proximal and distal diaphyses respectively. This bone augmentative effect resulted in 264% increase in bending strength of the fracture site and 148% increase of the same value in the adjacent areas of diaphyses. In conclusion, IMCO, using CPC in tibia of sheep, is safe and biocompatible with bone physiology and healing. It possibly can carry the osteopromotive effect of the CPCs to provide a sustained source of bone augmentation throughout the diaphysis. Although the results must be considered preliminary, this method has possible advantages over conventional methods of bone fixation at least in bones with compromised quality (i.e. osteoporosis and bone cysts), where rigid metal implants may jeopardize eggshell cortices.
    Matched MeSH terms: Calcium Phosphates/administration & dosage*
  3. A comprehensive review of milk fouling on heated surfaces
    Sadeghinezhad E, Kazi SN, Dahari M, Safaei MR, Sadri R, Badarudin A
    Crit Rev Food Sci Nutr, 2015;55(12):1724-43.
    PMID: 24731003 DOI: 10.1080/10408398.2012.752343
    Heat exchanger performance degrades rapidly during operation due to formation of deposits on heat transfer surfaces which ultimately reduces service life of the equipment. Due to scaling, product deteriorates which causes lack of proper heating. Chemistry of milk scaling is qualitatively understood and the mathematical models for fouling at low temperatures have been produced but the behavior of systems at ultra high temperature processing has to be studied further to understand in depth. In diversified field, the effect of whey protein fouling along with pressure drop in heat exchangers were conducted by many researchers. Adding additives, treatment of heat exchanger surfaces and changing of heat exchanger configurations are notable areas of investigation in milk fouling. The present review highlighted information about previous work on fouling, influencing parameters of fouling and its mitigation approach and ends up with recommendations for retardation of milk fouling and necessary measures to perform the task.
    Matched MeSH terms: Calcium Phosphates/chemistry
  4. Recent development on porous calcium phosphate ceramics for biomedical application
    Sopyan I
    Med J Malaysia, 2008 Jul;63 Suppl A:14-5.
    PMID: 19024961
    Porous calcium phosphate ceramics have found enormous use in biomedical applications including bone tissue regeneration, cell proliferation, and drug delivery. In bone tissue engineering it has been applied as filling material for bone defects and augmentation, artificial bone graft material, and prosthesis revision surgery. Their high surface area leads to excellent osteoconductivity and resorbability providing fast bone ingrowths. Porous calcium phosphate can be produced by a variety of methods. This paper discusses briefly fundamental aspects of porous calcium phosphate for biomedical applications as well as various techniques used to prepare porous calcium phosphate.
    Matched MeSH terms: Calcium Phosphates*
  5. Successful commercialisation of locally fabricated bioceramics for clinical applications
    Fazan F, Besar I, Osman A, Samsudin AR, Khalid KA
    Med J Malaysia, 2008 Jul;63 Suppl A:49-50.
    PMID: 19024978
    This paper chronicled the development of a locally produced bone graft substitute based on calcium phosphate bioceramics called "GranuMaS--from concepts to clinics, and finally to its successful commercialization all within 5-year duration. It was a Prioritized Research (PR) collaborative project of 5 institutions namely SIRIM, ANM, USM, UKM and IIUM, funded by MOSTI to the amount of approximately RM2.5 millions under RM8. This paper also highlighted the requirements needed in terms of technical expertise/manpower, facilities and infrastructure, and government/institutional supports, as well as the challenge faced in developing and commercializing such product.
    Matched MeSH terms: Calcium Phosphates*
  6. Differential osteogenic activity of osteoprogenitor cells on HA and TCP/HA scaffold of tissue engineered bone
    Ng AM, Tan KK, Phang MY, Aziyati O, Tan GH, Isa MR, et al.
    J Biomed Mater Res A, 2008 May;85(2):301-12.
    PMID: 17688285
    Biomaterial, an essential component of tissue engineering, serves as a scaffold for cell attachment, proliferation, and differentiation; provides the three dimensional (3D) structure and, in some applications, the mechanical strength required for the engineered tissue. Both synthetic and naturally occurring calcium phosphate based biomaterial have been used as bone fillers or bone extenders in orthopedic and reconstructive surgeries. This study aims to evaluate two popular calcium phosphate based biomaterial i.e., hydroxyapatite (HA) and tricalcium phosphate/hydroxyapatite (TCP/HA) granules as scaffold materials in bone tissue engineering. In our strategy for constructing tissue engineered bone, human osteoprogenitor cells derived from periosteum were incorporated with human plasma-derived fibrin and seeded onto HA or TCP/HA forming 3D tissue constructs and further maintained in osteogenic medium for 4 weeks to induce osteogenic differentiation. Constructs were subsequently implanted intramuscularly in nude mice for 8 weeks after which mice were euthanized and constructs harvested for evaluation. The differential cell response to the biomaterial (HA or TCP/HA) adopted as scaffold was illustrated by the histology of undecalcified constructs and evaluation using SEM and TEM. Both HA and TCP/HA constructs showed evidence of cell proliferation, calcium deposition, and collagen bundle formation albeit lesser in the former. Our findings demonstrated that TCP/HA is superior between the two in early bone formation and hence is the scaffold material of choice in bone tissue engineering.
    Matched MeSH terms: Calcium Phosphates*
  7. Calcium phosphate bone substitutes
    Ginebra MP, Aparicio C, Engel E, Navarro M, Javier Gil F, Planell JA
    Med J Malaysia, 2004 May;59 Suppl B:65-6.
    PMID: 15468821
    Matched MeSH terms: Calcium Phosphates/pharmacology*
  8. Surface characterization and corrosion behavior of calcium phosphate-base composite layer on titanium and its alloys via plasma electrolytic oxidation: A review paper
    Rafieerad AR, Ashra MR, Mahmoodian R, Bushroa AR
    Mater Sci Eng C Mater Biol Appl, 2015 Dec 1;57:397-413.
    PMID: 26354281 DOI: 10.1016/j.msec.2015.07.058
    In recent years, calcium phosphate-base composites, such as hydroxyapatite (HA) and carbonate apatite (CA) have been considered desirable and biocompatible coating layers in clinical and biomedical applications such as implants because of the high resistance of the composites. This review focuses on the effects of voltage, time and electrolytes on a calcium phosphate-base composite layer in case of pure titanium and other biomedical grade titanium alloys via the plasma electrolytic oxidation (PEO) method. Remarkably, these parameters changed the structure, morphology, pH, thickness and crystallinity of the obtained coating for various engineering and biomedical applications. Hence, the structured layer caused improvement of the biocompatibility, corrosion resistance and assignment of extra benefits for Osseo integration. The fabricated layer with a thickness range of 10 to 20 μm was evaluated for physical, chemical, mechanical and tribological characteristics via XRD, FESEM, EDS, EIS and corrosion analysis respectively, to determine the effects of the applied parameters and various electrolytes on morphology and phase transition. Moreover, it was observed that during PEO, the concentration of calcium, phosphor and titanium shifts upward, which leads to an enhanced bioactivity by altering the thickness. The results confirm that the crystallinity, thickness and contents of composite layer can be changed by applying thermal treatments. The corrosion behavior was investigated via the potentiodynamic polarization test in a body-simulated environment. Here, the optimum corrosion resistance was obtained for the coating process condition at 500 V for 15 min in Ringer solution. This review has been summarized, aiming at the further development of PEO by producing more adequate titanium-base implants along with desired mechanical and biomedical features.
    Matched MeSH terms: Calcium Phosphates/chemistry*
  9. Enhancement of thermal, mechanical and physical properties of polyamide 12 composites via hybridization of ceramics for bone replacement
    Abdullah AM, Mohamad D, Rahim TNAT, Akil HM, Rajion ZA
    Mater Sci Eng C Mater Biol Appl, 2019 Jun;99:719-725.
    PMID: 30889745 DOI: 10.1016/j.msec.2019.02.007
    This study reports the influence of ZrO2/β-TCP hybridization on the thermal, mechanical, and physical properties of polyamide 12 composites to be suited for bone replacement. Amount of 15 wt% of nano-ZrO2 along with 5,10,15,20 and 25 wt% of micro-β-TCP was compounded with polyamide 12 via a twin-screw extruder. The hybrid ZrO2/β-TCP filled polyamide 12 exhibited higher thermal, mechanical and physical properties in comparison to unfilled polyamide 12 at certain filler loading; which is attributed to the homogenous dispersion of ZrO2/β-TCP fillers particle in polyamide 12 matrix. The hybrid ZrO2/β-TCP filled PA 12 demonstrated an increment of tensile strength by up to 1%, tensile modulus of 38%, flexural strength of 15%, flexural modulus of 45%, and surface roughness value of 93%, as compared to unfilled PA 12. With enhanced thermal, mechanical and physical properties, the newly developed hybrid ZrO2/β-TCP filled PA 12 could be potentially utilized for bone replacement.
    Matched MeSH terms: Calcium Phosphates/chemistry
  10. Coatless alginate pellets as sustained-release drug carrier for inflammatory bowel disease treatment
    Md Ramli SH, Wong TW, Naharudin I, Bose A
    Carbohydr Polym, 2016 Nov 05;152:370-381.
    PMID: 27516284 DOI: 10.1016/j.carbpol.2016.07.021
    Conventional alginate pellets underwent rapid drug dissolution and failed to exert colon targeting unless subjected to complex coating. This study designed coatless delayed-release oral colon-specific alginate pellets for ulcerative colitis treatment. Alginate pellets, formulated with water-insoluble ethylcellulose and various calcium salts, were prepared using solvent-free melt pelletization technique which prevented reaction between processing materials during agglomeration and allowed reaction to initiate only in dissolution. Combination of acid-soluble calcium carbonate and highly water-soluble calcium acetate did not impart colon-specific characteristics to pellets due to pore formation in fragmented matrices. Combination of moderately water-soluble calcium phosphate and calcium acetate delayed drug release due to rapid alginate crosslinking by soluble calcium from acetate salt followed by sustaining alginate crosslinking by calcium phosphate. The use of 1:3 ethylcellulose-to-alginate enhanced the sustained drug release attribute. The ethylcellulose was able to maintain the pellet integrity without calcium acetate. Using hydrophobic prednisolone as therapeutic, hydrophilic alginate pellets formulated with hydrophobic ethylcellulose and moderately polar calcium phosphate exhibited colon-specific in vitro drug release and in vivo anti-inflammatory action. Coatless oral colon-specific alginate pellets can be designed through optimal formulation with melt pelletization as the processing technology.
    Matched MeSH terms: Calcium Phosphates/pharmacokinetics; Calcium Phosphates/chemistry
  11. Ion-Doped Silicate Bioceramic Coating of Ti-Based Implant
    Mohammadi H, Sepantafar M
    Iran Biomed J, 2016 Sep;20(4):189-200.
    PMID: 26979401
    Titanium and its alloy are known as important load-bearing biomaterials. The major drawbacks of these metals are fibrous formation and low corrosion rate after implantation. The surface modification of biomedical implants through various methods such as plasma spray improves their osseointegration and clinical lifetime. Different materials have been already used as coatings on biomedical implant, including calcium phosphates and bioglass. However, these materials have been reported to have limited clinical success. The excellent bioactivity of calcium silicate (Ca-Si) has been also regarded as coating material. However, their high degradation rate and low mechanical strength limit their further coating application. Trace element modification of (Ca-Si) bioceramics is a promising method, which improves their mechanical strength and chemical stability. In this review, the potential of trace element-modified silicate coatings on better bone formation of titanium implant is investigated.
    Matched MeSH terms: Calcium Phosphates/pharmacology; Calcium Phosphates/chemistry
  12. 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: Calcium Phosphates
  13. Fulltext An eight-week In Vivo study on the clinical signs of systemic toxicity and bone regenerative performance of composites containing beta tricalcium phosphate, hydrogel and melatonin in adult New Zealand rabbit (Oryctolagus cuniculus)
    Mohamed Abdelrasoul, Jahangir Bin Kamaldin, Jer Ping Ooi, Ahmed Abd El-Fattah, Gihan Kotry, Omneya Ramadan, et al.
    Malaysian Journal of Medicine and Health Sciences, 2020;16(102):38-45.
    MyJurnal
    Introduction: Melatonin (MEL) loaded alginate-chitosan/beta-tricalcium phosphate (Alg-CH/β-TCP) composite hy- drogel has been formulated as a scaffold for bone regeneration. MEL in the scaffold was anticipated to accelerate bone regeneration. The objective of this study is to observe signs of systemic toxicity and physical changes on surface defected bone for bone regenerative performance of the composite. Methods: The proximal-medial metaphyseal cortex of the left tibia of New Zealand white rabbit was the surgical site of the defect. A total of nine rabbits were randomly allocated to three groups; Group I; implanted with MEL loaded Alg-CH/β-TCP, Group II; Alg-CH/β-TCP and Group III defects were sham control. The rabbits were daily observed to determine systemic toxicity effects by composites. The physical changes to implanted site were observed using digital x-ray radiography and computerized tomography at weeks 0, 2, 4, 6 and 8 of post-implantation. Results: There were no clinical signs of systemic toxicity for all groups of rabbits. Digital radiography did not show adverse effects to the bone. Computerized tomography showed reduction in the area size and depth volume of the implantation site, but accelerated regeneration within the 8 weeks was not significantly different (P
    Matched MeSH terms: Calcium Phosphates
  14. Fulltext Role of organic and ceramic biomaterials on bone healing and regeneration: An experimental study with significant value in translational tissue engineering and regenerative medicine
    Moshiri A, Tekyieh Maroof N, Mohammad Sharifi A
    Iran J Basic Med Sci, 2020 Nov;23(11):1426-1438.
    PMID: 33235700 DOI: 10.22038/ijbms.2020.46228.10707
    Objectives: We investigated the role of various biomaterials on cell viability and in healing of an experimentally induced femoral bone hole model in rats.

    Materials and Methods: Cell viability and cytotoxicity of gelatin (Gel; 50 µg/µl), chitosan (Chi; 20 µg/µl), hydroxyapatite (HA; 50 µg/µl), nanohydroxyapatite (nHA; 10 µg/µl), three-calcium phosphate (TCP; 50 µg/µl) and strontium carbonate (Sr; 10 µg/µl) were evaluated on hADSCs via MTT assay. In vivo femoral drill-bone hole model was produced in rats that were either left untreated or treated with autograft, Gel, Chi, HA, nHA, TCP and Sr, respectively. The animals were euthanized after 30 days. Their bone holes were evaluated by gross-pathology, histopathology, SEM and radiography. Also, their dry matter, bone ash and mineral density were measured.

    Results: Both the Gel and Chi showed cytotoxicity, while nHA had no role on cytotoxicity and cell-viability. All the HA, TCP and Sr significantly improved cell viability when compared to controls (P<0.05). Both the Gel and Chi had no role on osteoconduction and osteoinduction. Compared to HA, nHA showed superior role in increasing new bone formation, mineral density and ash (P<0.05). In contrast to HA and nHA, both the TCP and Sr showed superior morphological, radiographical and biochemical properties on bone healing (P<0.05). TCP and Sr showed the most effective osteoconduction and osteoinduction, respectively. In the Sr group, the most mature type of osteons formed.

    Conclusion: Various biomaterials have different in vivo efficacy during bone regeneration. TCP was found to be the best material for osteoconduction and Sr for osteoinduction.

    Matched MeSH terms: Calcium Phosphates
  15. Fulltext Antibacterial efficacy and drug-release behavior study of β-tricalcium phosphate micro-granules against staphylococcus aureus and Escherichia coli
    Nor Hazliana Harun, Rabiatul Basria S.M.N. Mydin, Khairul Anuar Shariff, Nur Adila Rosdi, Davamunisvari Rames
    Malaysian Journal of Medicine and Health Sciences, 2020;16(3):202-206.
    MyJurnal
    Introduction: This study aims to investigate different residue sizes of β-tricalcium phosphate (β-TCP) micro-granules as carriers to assess antibacterial activity and drug-control release behavior of ampicillin (AMP-) and antimycotic (AMC-). Incorporation of antibiotic into the β-TCP micro-granules and it sustain release behavior could be used as alternative solution to reduce the risk of osteomyelitis and bone infections risks. Methods: Three different residue sizes (less than 300 µm, 300 µm and 600 µm) were prepared and coated with antibiotics solution (20 µg/µl of ampi- cillin and 100X antimycotic solution) by using two methods; dip and stream coating. After 72 h, 1.5 mL of distilled water was added to the treated (β-TCP) micro-granules at two different pH value (5.0 and 7.4). The extracted solution was further analyzed by Kirby Bauer disc diffusion test and spectrophotometer assay. Results: The solution con- taining AMC-(β-TCP) micro-granules with the size of 300 µm residue produced the largest inhibition zones against Escherichia coli (E. coli). All residue sizes coated with AMP- showed no antibacterial activity against both strains; Staphylococcus aureus (S. aureus) and E.coli. Additionally, the release behavior of AMC-(β-TCP) micro-granules was found not depending on the pH, but on the size of residue. Complete drug release was rapidly observed within 48
    h. Conclusion: Based on this findings, it showed AMC-(β-TCP) micro-granules had an antibacterial activity against Gram-negative strain. Specifically, it can reduced the growth rate of E. coli and the rapid release behavior of AMC- (β-TCP) micro-granules help in minimizing the risk-infections in early stage of implantation.
    Matched MeSH terms: Calcium Phosphates
  16. Fulltext Synthesis and characterization of β-tricalcium phosphate ceramic via sol-gel method
    Mohd Al Amin Muhamad Nor, Maryam Mohd Ridzuan, Zainal Arifin Ahmad
    Journal of Nuclear and Related Technologies, 2009;2009(1):199-205.
    MyJurnal
    Ceramic materials play key role in several biomedical applications. One of them is bone graft which is use in treating bone defect which caused by injury or osteoporosis. Calcium phosphates based ceramic are preferred as bone grafts in hard tissue engineering because of their chemical compositions are similar to the composition of human bone, superior bioresorbable and bioactivity. In this study, β-tricalcium phosphate (β-TCP) ceramic was synthesized by using sol-gel method. Phosphorous pentoxide (P2O5) and calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) were used as calcium and phosphate precursors. The effects of calcination temperature on the synthesis powder were studied using the XRD, SEM-EDS and FTIR techniques. It was found that calcination temperature greatly influence the purity of the synthesized powders. The β-TCP was the dominant phase with the formation of α-TCP at calcination temperature from 600 to 800°C. Pure β-TCP was obtained at calcination of 900°C. As the temperature increased to 1000°C, the β-TCP was decomposed to for calcium phosphate oxide (CPO). The sol-gel method has some advantages over other methods, mainly its simplicity and ability to produce pure β-TCP at lower calcination temperature.
    Matched MeSH terms: Calcium Phosphates
  17. Physico-Mechanical Properties of HA/TCP Pellets and Their Three-Dimensional Biological Evaluation In Vitro
    Kamalaldin N', Jaafar M, Zubairi SI, Yahaya BH
    Adv Exp Med Biol, 2019;1084:1-15.
    PMID: 29299875 DOI: 10.1007/5584_2017_130
    The use of bioceramics, especially the combination of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), as a three-dimensional scaffold in bone engineering is essential because together these elements constitute 60% of the bone content. Different ratios of HA and β-TCP were previously tested for their ability to produce suitable bioceramic scaffolds, which must be able to withstand high mechanical load. In this study, two ratios of HA/TCP (20:80 and 70:30) were used to create pellets, which then were evaluated in vitro to identify any adverse effects of using the material in bone grafting. Diametral tensile strength (DTS) and density testing was conducted to assess the mechanical strength and porosity of the pellets. The pellets then were tested for their toxicity to normal human fibroblast cells. In the toxicity assay, cells were incubated with the pellets for 3 days. At the end of the experiment, cell morphological changes were assessed, and the absorbance was read using PrestoBlue Cell Viability Reagent™. An inversely proportional relationship between DTS and porosity percentage was detected. Fibroblasts showed normal cell morphology in both treatments, which suggests that the HA/TCP pellets were not toxic. In the osteoblast cell attachment assay, cells were able to attach to the surface of both ratios, but cells were also able to penetrate inside the scaffold of the 70:30 pellets. This finding suggests that the 70:30 ratio had better osteoconduction properties than the 20:80 ratio.
    Matched MeSH terms: Calcium Phosphates
  18. Fulltext Repair of segmental load-bearing bone defect by autologous mesenchymal stem cells and plasma-derived fibrin impregnated ceramic block results in early recovery of limb function
    Ng MH, Duski S, Tan KK, Yusof MR, Low KC, Rose IM, et al.
    Biomed Res Int, 2014;2014:345910.
    PMID: 25165699 DOI: 10.1155/2014/345910
    Calcium phosphate-based bone substitutes have not been used to repair load-bearing bone defects due to their weak mechanical property. In this study, we reevaluated the functional outcomes of combining ceramic block with osteogenic-induced mesenchymal stem cells and platelet-rich plasma (TEB) to repair critical-sized segmental tibial defect. Comparisons were made with fresh marrow-impregnated ceramic block (MIC) and partially demineralized allogeneic bone block (ALLO). Six New Zealand White female rabbits were used in each study group and three rabbits with no implants were used as negative controls. By Day 90, 4/6 rabbits in TEB group and 2/6 in ALLO and MIC groups resumed normal gait pattern. Union was achieved significantly faster in TEB group with a radiological score of 4.50 ± 0.78 versus ALLO (1.06 ± 0.32), MIC (1.28 ± 0.24), and negative controls (0). Histologically, TEB group scored the highest percentage of new bone (82% ± 5.1%) compared to ALLO (5% ± 2.5%) and MIC (26% ± 5.2%). Biomechanically, TEB-treated tibiae achieved the highest compressive strength (43.50 ± 12.72 MPa) compared to those treated with ALLO (15.15 ± 3.57 MPa) and MIC (23.28 ± 6.14 MPa). In conclusion, TEB can repair critical-sized segmental load-bearing bone defects and restore limb function.
    Matched MeSH terms: Calcium Phosphates/administration & dosage*
  19. Reinforcement of calcium phosphate cement with multi-walled carbon nanotubes and bovine serum albumin for injectable bone substitute applications
    Chew KK, Low KL, Sharif Zein SH, McPhail DS, Gerhardt LC, Roether JA, et al.
    J Mech Behav Biomed Mater, 2011 Apr;4(3):331-9.
    PMID: 21316621 DOI: 10.1016/j.jmbbm.2010.10.013
    This paper presents the development of novel alternative injectable calcium phosphate cement (CPC) composites for orthopaedic applications. The new CPC composites comprise β-tri-calcium phosphate (β-TCP) and di-calcium phosphate anhydrous (DCPA) mixed with bovine serum albumin (BSA) and incorporated with multi-walled carbon nanotubes (MWCNTs) or functionalized MWCNTs (MWCNTs-OH and MWCNTs-COOH). Scanning electron microscopy (SEM), compressive strength tests, injectability tests, Fourier transform infrared spectroscopy and X-ray diffraction were used to evaluate the properties of the final products. Compressive strength tests and SEM observations demonstrated particularly that the concomitant admixture of BSA and MWCNT improved the mechanical properties, resulting in stronger CPC composites. The presence of MWCNTs and BSA influenced the morphology of the hydroxyapatite (HA) crystals in the CPC matrix. BSA was found to act as a promoter of HA growth when bounded to the surface of CPC grains. MWCNT-OH-containing composites exhibited the highest compressive strengths (16.3 MPa), being in the range of values for trabecular bone (2-12 MPa).
    Matched MeSH terms: Calcium Phosphates/chemistry*
  20. Fulltext Comparative evaluation of application of different fluoride varnishes on artificial early enamel lesion: An in vitro study
    Majithia U, Venkataraghavan K, Choudhary P, Trivedi K, Shah S, Virda M
    Indian J Dent Res, 2016 Sep-Oct;27(5):521-527.
    PMID: 27966511 DOI: 10.4103/0970-9290.195642
    INTRODUCTION: In an attempt to manage noncavitated carious lesions noninvasively through remineralization, a range of novel fluoride varnishes with additional remineralizing agents have been made available for clinical application.

    AIM AND OBJECTIVES: The aim of this study was to compare and evaluate the remineralization potential of three commercially available varnishes on artificial enamel lesions.

    MATERIALS AND METHODS: This in vitro study involves eighty intact enamel specimens prepared from premolars extracted for orthodontic purposes. After specimen preparation, the eighty samples were divided randomly into two groups (n = 40) for measurement of baseline surface Vickers microhardness and baseline calcium/phosphorus ratio (% weight) through EDAX testing. Thereafter, the specimens were subjected to demineralization for 96 h to induce initial enamel lesions and the measurements were repeated. Following demineralization, each of the two groups was divided randomly into four subgroups (n = 10) from which one was used as the control group and the others three were allotted to each of the three test varnishes. After varnish application, all the specimens were subjected to a pH cycling regimen that included alternative demineralization (3 h) and remineralization (21 h) daily, for 5 consecutive days. The Vickers microhardness and EDAX measurements were then repeated.

    RESULTS: One-way ANOVA and post hoc Tukey's tests were conducted for multiple group comparison. All the three commercially available varnishes were capable of remineralizing initial enamel lesions that were induced artificially. No difference was noted in the remineralizing efficacy of the varnishes despite their different compositions. MI Varnish™ (casein phosphopeptide-amorphous calcium phosphate fluoride varnish) showed slightly better recovery in surface microhardness as compared to the other two varnishes.

    CONCLUSION: All the varnishes used in this in vitro study are capable of reversing early enamel lesions.
    Matched MeSH terms: Calcium Phosphates/pharmacology
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