Soaking In Simulated Body Fluid Research Articles

Ageing of TotalFill BC Sealer and MTA Fillapex in Simulated Body Fluid.

Objective:The bioactivities of TotalFill BC and the MTA Fillapex sealers were evaluated.Methods:Sixty horizontal root sections were enlarged to size 5 Gates Glidden and randomly divided into six groups (n=10 in each group). In Groups 1–3, sections were filled with TFBCS, while sections in groups 4–6 were filled with MTAFS. Specimens from groups 1 and 4 were soaked in simulated body fluid (SBF) for one day, those from groups 2 and 5 for one week, and those from groups 3 and 6 for two months. All specimens were processed for scanning electron microscope (SEM) examination. Apatite precipitation on sealer and sealer–dentine interfaces was quantified using image analysis software (ImageJ). Energy dispersive X-ray (EDX) was used to analyse calcium (Ca) and phosphate (P) contents of surface precipitation on which calculation of the calcium phosphate (Ca/P) ratio was based.Results:TFBCS samples, regardless of the duration of SBF soaking, yielded a significantly higher surface area of precipitation compared to MTAFS (P<0.05); such precipitation increased over time, and the differences among the three time-points were also statistically significant. Following one day of SBF soaking, MTAFS samples showed only limited precipitation that started to appear after one week. EDX showed that Ca content and the Ca/P ratio of surface deposits on TFBCS samples increased over time with no difference between one week and two months of SBF soaking. The Ca content and Ca/P ratio of surface deposits on MTAFS were significantly lower than that of TFBCS samples regardless of the SBF soaking time.Conclusion:Ageing TotalFill BC sealer in SPF can induce considerable apatite formation. In addition, the TotalFill BC sealer surface showed high Ca2+ ion release as reflected by the formation of apatite with a high Ca/P ratio. These bioactivity features increased over time. In comparison, the MTAFS appears to have lower and delayed bioactivity.

Apatite Formation on Zirconia (Y-TZP) Coated with Carbonate Apatite in Simulated Body Fluid

Abstract. Various bioactive calcium phosphates such as hydroxyapatite (HA) and carbonate apatite (CO3Ap) have been widely studied due to their biocompatibility and osteoconductivity when implanted into bone defects. CO3Ap has the ability to adapt bone structure and induce bone regeneration; so that it can be categorized as resorbable bioactive materials. CO3Ap induced much stronger response such as cell adhesion and actin ring formation to osteoclast-like cells rather than HA. The aim of this study is to evaluate the bioactivity on zirconia (Y-TZP) coated with CO3Ap using simulated body fluid (SBF). Twenty Y-TZP ZrO2 disks with a 12-mm diameter and 1-mm thickness were employed as the samples. The disks were divided into two groups which the control group without CO3Ap coating and tested group with CO3Ap coating. Disks samples are dipped into CO3Ap suspension for one minute and stored in 37°C incubator for 24 hours. The disks were soaked in SBF for 1, 4, and 7 day(s) at 36.5°C. The obtained apatite crystals were characterized by scanning electron microscopy (SEM). It was found that the apatite formation on the tested group was greater than the control group. The EDS pattern showed the presence of Ca and P on the control and tested group after SBF soaking, which indicate the apatite deposition on the disks’ surface. However, the Ca and P on the tested group was higher compared to the control group. The formation of apatite layer on the disks’ surface is bioactivity indicator of CO3Ap.

Mechanistic studies of biomineralisation on silver incorporated anatase TiO2.

Here we report silver incorporated anatase TiO2 developed on Ti metal by H2O2-AgNO3 and heat treatment to have faster biomineralisation or apatite-forming ability in simulated body fluid (SBF). Apatite-forming ability has been investigated concerning heat treatment temperatures ranges, 400-800°C and duration of soaking period in SBF. The apatite formation showed an increasing trend with increase in the heat treatment temperatures up to 600°C and beyond that the Ti metal lost this ability. XRD as wells as Raman results of such chemical and heat-treated Ti metal at different temperatures further correlates the apatite nucleation directly in relation with that of anatase to rutile TiO2 formation. Further, a time dependent apatite mineralisation study by XPS revealed simultaneous calcium and phosphate deposition at the early stage of soaking in SBF. Therefore, the apatite nucleation in the present chemically treated Ti metal depends on the crystalline phase of TiO2 formed by H2O2 and heat treatment along with Ag+ ion release.

Preparation and properties of biomimetic hydroxyapatite-based nanocomposite utilizing bamboo fiber

Biomass fiber is currently one of the most attractive research pursuits in the biomaterials field. In this study, bamboo fiber (BF) was firstly chosen to replace other polymers to prepare nano-hydroxyapatite (n-HA)-based nanocomposite, and the effects of different states, treatments methods, the addition amounts and addition methods of BF on the formation of n-HA on BF fiber and the corresponding n-HA/BF composites were investigated by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, electromechanical universal tester, in vitro soaking in simulated body fluid and in vitro cell culture experiment. Results demonstrated that n-HA with the irregular morphology was attached on BF fibers, and it could be hybridized with BF to form n-HA/BF composite, however, there was subtle difference of the crystallinity, size and formed amount of n-HA attached on the different BF fibers, which brought about different surface properties of the n-HA/BF composites. And 30 wt% BF endowed the n-HA/BF composite with the best mechanical properties, whose was by far higher than that of pure n-HA. In addition, in vitro simulated body fluids soaking results indicated that n-HA/BF composites displayed different water absorption rates, and all n-HA/BF composites could promote the apatite deposit. Meanwhile, the n-HA/BF composites exhibited good cytocompatibility, including attachment and proliferation. All results proved that single BF polymer could be used to act as the organic matrix to prepare n-HA-based nanocomposite by replacing collagen component of natural bone, and the alkali treated and undissolved BF with 30 wt% addition amount by precipitated method was the best appropriate condition to prepare the ideal n-HA/BF composite. Consequently, the study would open up a new application of natural BF in the biomedical field. In this manuscript, bamboo fiber (BF) was firstly chosen to replace other polymers to prepare nano-hydroxyapatite (n-HA)-based nanocomposite, and the effects of different states, treatments methods, the addition amounts and addition methods of BF on the formation of n-HA were investigated. Results demonstrated that n-HA with the irregular morphology was attached onto BF and hybridized with BF, and n-HA possessed different crystallinity and size, which brought about different properties of the n-HA/BF composites. Overall, the alkali treated and undissolved BF with 30 wt% addition amount by co-precipitated method was the best appropriate condition to prepare the ideal n-HA/BF composite, which had a great potential to be used as bone materials. The study proved that single BF could replace other polymers to develop n-HA-based nanocomposite used as bone materials, which would open up a new idea to utilize BF in biomedical field. SEM micrographs of samples. (a) Pure n-HA, (b) alkali/undissolved/precipitated, (c) unalkali/undissolved/precipitated, (d) alkali/dissolved/co-precipitated, (e) alkali/undissolved/blended, (f) acid/undissolved/precipitated, (A) 20%BF/n-HA, (B) 30%BF/n-HA, (C) 40%BF/n-HA

Novel Bifunctional Nanofiller (Bioactive\Antimicrobial) for Improving Dental Adhesives Efficacy

Purpose: The objective of this study was to develop novel bio-composite Nanofiller (Quaternary polyethyleneimine\ Hydroxyapatite, QPEI/HAp), which combines the antibacterial activity of polymeric quaternary ammonium salt and the multi-advantages of Hydroxyapatite nanoparticles for improving biological and physico-mechanical properties of Dental Adhesives. Materials and Methods: Hydroxyapatite (HAp) nano rods were produced by hydrothermal process and coated by Polyethyleneimine (PEI) via electrostatic adsorption, followed by two steps polymeric reaction; tertiary amination and quaternization. The resulting powder was characterized using XRD, FTIR and TEM before and after polymer coating, and bioactivity was evaluated after 7 days soaking in simulated body fluid using XRD analysis. An experimental ethanolbased one-bottle adhesive resin was formulated with 0.2, 0.5, 1, 2 and 5% QPEI/HAp nanofiller. The formulated adhesive resins were evaluated for their colloidal stability, antibacterial activity, Ultimate Tensile Strength, and Micro-Shear bond strength to dentin. Results: Powder characterization confirmed successful surface modification of Hydroxyapatite nanoparticles with PEI polymer; the particles presented a high crystallinity with typical chemical groups and mean size around 20 nanometers. XRD analysis revealed nucleation of apatite crystals on the surface of QPEI/HAp nanoparticles after soaking in SBF; confirming their bioactivity. Lower contents of modified nanoparticles showed little or no aggregation tendency and good colloidal stability in the adhesive solution with Zeta potential of 30.6 mV. Antibacterial outcomes of PEI against S. mutans was significantly higher than that of MDPB in Clearfil Protect bond; a commercial adhesive used as control (P&lt;0.05). The addition of 0.2 wt. % modified nano-hydroxyapatite resulted in higher values of Ultimate Tensile and Micro-Shear bond strength than other tested adhesives and commercial Clearfil S3 Bond (all-in-one adhesive); (P&lt;0.05). Conclusion: Incorporation of 0.2 wt. % QPEI-HAp nanoparticles significantly improved the adhesive properties and may be promising multifunctional filler for dental adhesive resin.

Effect of nanosilica addition on bioactivity and in vivo properties of calcium aluminate cement

This study aims at assessing the influence of nanosilica on the bioactivity and mechanical properties of calcium aluminate cement. For this purpose, nanosilica was applied as a replacement for calcium aluminate cement at 0, 2, 5 and 8 wt%. The main components were analyzed by scanning electron microscope coupled with surface imaging and elemental analysis, fourier transform infrared spectroscopy and X-ray diffraction analysis. To estimate the bioactivity of specimens, hydroxyapatite formation on the surface of cement paste was investigated in the simulated body fluid solution. In addition, in vivo evaluation of calcium aluminate cement was performed in subcutaneous tissue of rats. To investigate the mechanical properties, both compressive and flexural strengths were also measured. The results revealed that by increasing nanosilica up to 8 wt%, the strength enhanced. Moreover all cement paste samples with various amounts of nanosilica represented good bioactivity because of formation of bonelike apatite layer on the surface of specimens within 28 days after soaking in simulated body fluid. In vivo experiments indicated that the cement sample was absorbed by the tissue and there was no infection at the implant site. Based on the in vitro and in vivo results, the specimen with 2 wt% nanosilica represented the highest bioactivity.

Bioactivity of nitric acid and calcium chloride treated carbon-fibers reinforced polyetheretherketone for dental implant

Carbon fiber reinforced Polyetheretherketone (PEEK) acquires mechanical strength which is close to human bone, but PEEK is inert, which can affect the bone fixation and osseointegration during dental implantation. To improve the bioactivity of PEEK, surface modification with nitric acid (HNO3) and calcium chloride (CaCl2) were utilized in this work. As the results, the hydrophilicity of the treated samples is significantly improved with the reduced roughness and attached nitro-functional group on its surface. The biological activity of CF/PEEK samples are enhanced by apatite formation evaluation soaking in simulated body fluid (SBF) in vitro after HNO3 and CaCl2 treatment. Moreover, the cytotoxicity experiments results confirm that surface treatment with HNO3 and CaCl2 is not harmful to the compatibility and safety of the cells.

Development of Vitroceramic Coatings and Analysis of Their Suitability for Biomedical Applications

Within the field of tissue engineering, thin films have been studied to improve implant fixation of metallic or ceramic materials in bone, connective tissue, oral mucosa or skin. In this context, to enhance their suitability as implantable devices, titanium-based substrates received a superficial vitroceramic coating by means of laser ablation. Further, this study describes the details of fabrication and corresponding tests in order to demonstrate the bioactivity and biocompatibility of the newly engineered surfaces. Thus, the metallic supports were covered with a complex material composed of SiO2, P2O5, CaO, MgO, ZnO and CaF2, in the form of thin layers via a physical deposition techniques, namely pulsed laser deposition. The resulting products were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning and transmission electron microscopy coupled with energy dispersive X-ray spectroscopy, selected area electron diffraction, and electron energy loss spectroscopy. It was found that a higher substrate temperature and a lower working pressure lead to the highest quality film. Finally, the samples biocompatibility was assessed and they were found to be bioactive after simulated body fluid soaking and biocompatible through the MTT cell viability test.

Synthesis and Investigation into Apatite-forming Ability of Hydroxyapatite/Chitosan-based Scaffold

Synthesis and Investigation into Apatite-forming Ability of Hydroxyapatite/Chitosan-based Scaffold

Fabrication of porous micro-nanostructured networks on Ti6Al4V for faster hydroxyapatite deposition in SBF

Abstract Surfaces with porous micro-nanostructured networks on Ti6Al4V substrates were successfully fabricated via sandblast, acid-alkali etching treatment. Wettability and hydroxyapatite (HA)-forming ability of the multilevel structured Ti6Al4V surfaces were investigated. Water contact angles and simulated body fluid (SBF) contact angles of 6 μl droplets on the resulting surfaces were as low as 0°, which could be attributed to the formation of hydrophilic TiO2 layer and larger specific surface area. Furthermore, after soaking in SBF for 1 day, a homogeneous HA layer was formed on the multilevel structured Ti6Al4V surface, whereas surface of original Ti6Al4V showed few HA precipitates even after 7 days of SBF immersion, suggesting that the fabricated structure was beneficial to faster HA deposition in SBF.

In vitro bioactivity, molecular structure and mechanical properties of zirconia-carbonated hydroxyapatite nanobiocomposites sintered at different temperatures

Zirconia-carbonated hydroxyapatite (ZrO2-CHA) nanocomposites powders, with various CHA contents, have been prepared using high energy ball milling. In order to investigate the influence of their exposure to different firing temperatures; namely 800, 1000, 1200, 1400 and 1500 °C on their molecular structure and microstructure, X-ray diffraction (XRD) technique, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), respectively were employed. Additionally, their mechanical properties were also measured. Then, the in vitro bioactivity of the sintered samples, at different temperatures, was examined by FTIR spectroscopy and SEM after their soaking in simulated body fluid for 10 days. The obtained results pointed out that the elevation of sintering temperatures to 1000 °C caused fair densification and good mechanical properties irrespective to the partial degenartion of CHA and the formation of tricalcium phosphate (TCP) and calcium zirconate (CaZrO3) phases. However, further increase of sintering temperature led to dramatic decreases in these properties and then, they were significantly enhanced by the increasing of sintering temperature up to 1500 °C. The formation of the abovementioned phases negatively affected the bioactivity of these nanocomposites. Calculated molecular electrostatic potential confirmed the reactivity of TCP and CaZrO3 phases.

Effect of surface chemical modifications on the bioactivity of carbon fibers reinforced epoxy composites

Carbon fibers reinforced epoxy (CF/epoxy) composites have been used in orthopedic and dental implants. However, the inert surface of CF/epoxy composites cannot show ability of forming direct bone bonding with autologous bone during implantation. In order to improve the bioactivity of CF/epoxy composites, the different chemical modifications (concentrated sulfuric acid (97 wt%), CaCl2 solution, concentrated sulfuric acid (97 wt%) + CaCl2 solution) were used to modify its original surface. The bioactivity of modified CF/epoxy composites was evaluated by in vitro apatite formation ability in simulated body fluids (SBF). The result showed that -SO3H and Ca2+ were introduced on the of sample surface after chemical modification. Samples modified with concentrated sulfuric acid (97 wt%) and CaCl2 solution showed the best bioactivity. In addition, a uniform and dense apatite coating was formed on the surface of functionalized CF/epoxy composites after soaking in SBF and the presence of -SO3H would significantly improve the bond between the coating and the substrate. The transformation process of apatite morphology during its formation and the mechanism of apatite formation on the functionalized CF/epoxy composites were also analyzed systematically.

Synthesis and characterization of a novel freeze‐dried silanated chitosan bone tissue engineering scaffold reinforced with electrospun hydroxyapatite nanofiber

AbstractNovel chitosan scaffolds containing different weight ratios of electrospun hydroxyapatite nanofibers (n‐HAs) were fabricated. The fibers possessed diameters in the range 110–170 nm. A fixed concentration of glycidyloxypropyl‐trimethoxysilane (GPTMS) as a crosslinking agent was added to the chitosan solution (CG). The porosity percentage was increased when GPTMS and n‐HAs were added to the chitosan structure. The presence of GPTMS in the chitosan structure caused a decrease in the average pore size. The pores were more irregular in shape than pure chitosan and CG scaffolds when n‐HAs were added. A uniform distribution of n‐HAs was seen for a chitosan‐GPTMS hybrid scaffold containing 25 wt% n‐HAs (CGH25) using energy dispersive X‐ray spectroscopy and mapping. The best values of compressive strength and elastic modulus were achieved for CGH25. The swelling ratio was decreased on adding GPTMS to the chitosan scaffold. Different morphologies of hydroxyapatite deposits on the surface of CG and CGH25 (string‐likeversusneedle‐like precipitates) were observed after 14 days of soaking in simulated body fluid. For CGH25, the viability of MG‐63 osteoblastic cells improved with respect to CG for up to 72 h of cell culture. These results reveal the potential of the chitosan‐CGH25 scaffold for use in bone tissue engineering. © 2019 Society of Chemical Industry

Synthesis and evaluation of the bioactivity of fluorapatite\u201345S5 bioactive glass nanocomposite

This research study concerns the evaluations of nano-biocomposite ceramics’ characteristics and biocompatibility. A nanocomposite with 45S5 bioactive glass base has been synthesized by sol–gel method. The synthesized nanocomposites were characterized with the help of different techniques, using field-emission scanning electron microscope, X-ray powder diffraction, energy-dispersive X-ray spectroscopy to evaluate the crystal structure, microstructure, and the morphology of the nanocomposite. The results indicated that the synthesis of 45S5 bioactive glass–fluorapatite nanocomposites produced an average particle size of about 20–30 nm and percentages of crystallinity of about 70–90%. fluorapatite–45S5 bioactive glass nanocomposites were characterized in terms of their degradation by determining the weight change percentages, pH changes, the ion release and in terms of bioactivity by checking the apatite layer formation using a solution of simulated body fluid (SBF). The results showed non-cytotoxicity and the formation of a thick apatite layer on the synthesized nanocomposites within 28 days after soaking in SBF. This is an indication of desirable bioactivity in the synthesized particles.

Freeze-cast composite scaffolds prepared from sol-gel derived 58S bioactive glass and polycaprolactone

This work deals with the preparation of freeze-cast scaffolds using sol-gel derived 58S bioactive glass and a hypoeutectic naphthalene-camphor mixture as the starting powder and freezing vehicle, respectively. After the freeze-casting step, samples were air sintered at 1250 °C for 2 h, which led to the crystallization of 58S. The obtained scaffolds were subsequently infiltrated with poly(ε-caprolactone) (PCL), a biodegradable polymer with potential application for bone tissue repair. The prepared materials were examined by helium pycnometry, laser granulometry, scanning electron microscopy (SEM), Archimedes tests, X-ray microtomography (micro-CT), Fourier transform infrared spectroscopy (FTIR), N2 adsorption, X-ray diffraction (XRD), and uniaxial compression tests. Samples cytotoxicity was evaluated by (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium reduction (MTT) and LIVE/DEAD assays. Their biocompatibility was also examined after soaking in a simulated body fluid (SBF) solution at 37 °C for up to 14 days. It was observed that the infiltration of PCL into the 58S scaffolds greatly increased their mechanical stability. Moreover, it was shown that these composites displayed a high cell viability (above 70%), which reveals that they did not interfere in the production of osteoblast cells. A hydroxyapatite coating was observed on the samples surface upon soaking in SBF, reinforcing that they are biocompatible materials. As far as we know, this is the first time that freeze-cast scaffolds were obtained using sol-gel derived 58S particles and a naphthalene-camphor mixture. Besides, as the infiltration of PCL into freeze-cast bioactive glass scaffolds improved their mechanical stability without impairing their bioactivity, this is a promising approach to prepare samples for load-bearing applications in bone tissue engineering.

Cu-Releasing Bioactive Glass Coatings and Their in Vitro Properties.

Bioactive glasses are well-known materials suitable for bone-related applications thanks to their biocompatibility and osteoconductivity. In order to improve their in vivo performance, the modification of the glass composition by adding ions with specific biological functions is required. As copper (Cu) possesses antibacterial properties, in this study, 5 wt % of CuO has been added to the 45S5 bioactive glass composition. The investigation of the effect of the Cu-containing bioactive glass on cellular behavior has revealed that the presence of Cu induces an early differentiation of human mesenchymal stem cells through osteoblast phenotype, promotes the expression of anti-inflammatory interleukin, and reduces proinflammatory interleukin expression. With the aim to produce coatings with antibacterial properties, the Cu-containing bioactive glass was used as the target material for the pulsed laser deposition (PLD) of bioactive thin films. PLD experiments were carried out at different substrate temperatures to study the effect on the film's characteristics. All of the films are compact, crack-free, and characterized by a rough morphology and good wettability. The in vitro bioactivity was demonstrated by the apatite growth on the coating surface, after soaking in simulated body fluid, revealed by Raman spectroscopy and scanning electron microscopy-energy dispersive X-ray analyses. The antibacterial study proved that the material showed more effective activity against three Gram-negative bacteria ( Pseudomonas aeruginosa, Escherichia coli, Salmonella enterica) rather than against Gram-positive bacteria ( Staphylococcus aureus).

Fabrication and up-conversion fluorescence property of Er3+/Yb3+co-doped Ca-Si-Ti biomaterials

This work demonstrates bulk-type up-conversion biomaterials which could be used as a bone repair material with the ability to monitor bone mineralization. Er3+/Yb3+ co-doped Ca-Si-Ti (CST3: TiO2 content is 30 mol%) bulk biomaterials were prepared via containerless processing technique in an aerodynamic levitation furnace and with subsequently heat treatment. The up-conversion fluorescence property was influenced by Yb3+ doping concentration, heat-treatment and mineralization in simulated body fluid (SBF). Optimum emission intensities were obtained for the sample with 20 mol% of Yb3+ doping concentration and heat treatment at 937 °C for 2 h. Hydroxyapatite (HAP) deposition was observed on the surface of the samples after soaking in SBF for 14 days, and the up-conversion fluorescence intensity of the samples decreased with the increase of soaking time. This indicates that Er3+/Yb3+ co-doped CST3 materials are bioactive, in which the HAP mineralization in bone repair could be monitored by measuring the intensity change of up-conversion fluorescence.

Characterization of chicken bone waste-derived hydroxyapatite and its functionality on chitosan membrane for guided bone regeneration

The objective of this research is to prepare asymmetric resorbable membrane based on the hybrid of chitosan (CS) and natural hydroxyapatite (HA) for guided bone regeneration. Briefly, HA with optimum compositional, structural and morphological properties was initially prepared from chicken bone waste via simple calcination. Thereafter, the prepared HA was incorporated into CS to form composite membrane, where the impact of filler loading on the characteristics of resulting membranes were further evaluated. SEM revealed that all composite membranes displayed an asymmetric smooth-rough surface, in which the coarseness of the rough surface increased when the HA content increased. Furthermore, the HA-impregnated membrane exceeding 10 phr loading exhibited improved bioactivity in comparison with pristine sample, being able of developing apatitic layer after 4 weeks of soaking in simulated body fluid. Overall, all membranes degraded less than 22% of the initial weight after 2 months of incubation period, where their degradation rate decrease further as HA loading increase. These findings significantly demonstrate the feasibility of chicken bone-derived HA to be employed as osteogenic filler to augment and tailor the biological characteristics and degradation behaviour of CS membrane for guided bone regeneration.

MTA HP Repair stimulates in vitro an homogeneous calcium phosphate phase coating deposition.

BackgroundTo study the mineralization capacity in vitro of the bioceramic endodontic material MTA HP Repair.Material and MethodsBioactivity evaluation in vitro was carried out, by soaking processed cement disk in simulated body fluid (SBF) during 168 h. The cement surface was studied by Fourier transform infrared spectroscopy (FT-IR), field emission gun scanning electron microscopy (FEG-SEM) and energy dispersive X-ray analysis (EDX). Release to the SBF media of ionic degradation products was monitored using inductively coupled plasma atomic emission spectroscopy (ICP-AES).ResultsFT-IR showed increasing formation of phosphate phase bands at 1097, 960, 607 and 570 cm-1 with prolonged SBF soaking. FEG-SEM analysis reveals that HP produces a effectively surface covering consisting in homogeneous spherical phosphate phase aggregates with an average diameter of 0.5-1.0 µm. EDX analysis comparing un-treated (hydrated), 24 h and 72 h SBF treated surfaces of MTA HP Repair revealed phosphate deposition after 24 h, with high phosphorous/silicon element ratio signal measured after 24 h, indicating a very high phosphate phase deposition for this material.ConclusionsThe study shows that MTA HP Repair produces a quick and effective bioactive response in vitro in terms of crystalline calcium phosphate surface coating formation. The high bioactive response of MTA HP Repair makes it an interesting candidate for endodontic use as repair cement. Key words:Bioactive endodontic cements, bioactive response, MTA HP Repair.

A novel method to enhance magnetic property of bioactive glass-ceramics for hyperthermia

In this study, a novel method was proposed to enhance the magnetic property of magnetic bioactive glass-ceramic (MBGC) using graphite-modified magnetite. The crystalline composition, chemical structure, in vitro bioactivity, magnetic property, heat generating ability, cytotoxicity and the hyperthermia treatment effectiveness of the synthesized material were investigated thoroughly. The results revealed that the addition of graphite could prevent the magnetite from being oxidized. The main phases of the as-prepared material were found to be Fe3O4, Ca2.87Fe0.13(SiO3)3 and Ca2SiO4 in the CaO-SiO2-MgO-CaF2-P2O5-Fe3O4 system. Moreover, the material was bioactive and hydroxyapatite was observed on the surface after soaking in simulated body fluid (SBF) for 10 d. Under a magnetic field of 1.6 × 106 A m−1, the saturation magnetization of MGBC was about 10.6 A m2 Kg−1, while that of the contrast sample was only 2.9 A m2 kg−1. When exposed to an alternating magnetic field (252 kHz, 1.9 × 103 A m−1) for about 20 s, a temperature rise of 20 °C could be observed on the sample surface. MTT assay results showed that the material had no cytotoxicity for VX2 cells. Moreover, the hyperthermia treatment experiments were carried out by exposing the block samples (Φ8 × 2 mm) and VX2 cells simultaneously to the alternating magnetic field for 20 min. Only about 30% cells survived after the treatment, and dead cells were observed around the material. Therefore, this novel material could have potential applications for clinical hyperthermia treatment.