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Effect of CaF2/P2O5 ratios on physical and mechanical properties of novel CaO–Na2O–B2O3–SiO2 glasses
Abstract
This paper outlines the fabrication of bioactive glass derived from waste eggshells as a source of calcium via the melt and water quenching method. The influence of the CaF2/P2O5 ratio on the physical, structural and mechanical properties of bioglass samples was investigated. XRD confirmed the amorphous structure, while the presence of Si–O–Si, P–O, and C–O indicated the formation of bioglass samples. It was found that increasing CaF2 content with appropriate P2O5 content could improve the mechanical properties of the bioglass. The increase in density can significantly impact the bioglass samples’ compressive strength and vickers microhardness. The bioglass with CaF2/P2O5 ratio of 6/4 possessed better properties, showing the optimal compressive strength (48.98 ± 0.11 MPa) and vickers microhardness (3.09 ± 0.07 GPa), which is compatible with the human enamel and commercial bioglass. Thus, the findings seem to contribute to a prospective cost-effective waste-derived bioglass system used in dental applications.
... Additionally, since the vitrified bond prepared in this way is amorphous glassy phase, its softening temperature is low, thus effectively reducing the sintering temperature. However, glassy vitrified bonds prepared by melt quenching generally require thorough melting of the raw materials at temperatures above 1200 • C to ensure uniform mixing, which consumes a considerable amount of energy [16,17]. Therefore, it is extremely important to develop new vitrified bonds that can be sintered at low temperatures, have superior performance, and are more energy-efficient and environmentally friendly. ...
... Materials 2024,17, 1799 ...
Currently, the sol-gel technique is employed in the synthesis of high-performance vitrified bonds; however, its application in the fabrication of stacked abrasives has been minimally explored. Furthermore, the methods utilized in the production of abrasive particles for stacked abrasives are technically challenging and incur high costs, which hinders their actual industrial application. Consequently, this study utilizes the sol-gel approach to synthesize a Na2O-B2O3-SiO2 ternary system vitrified bond powder and employs a molding and crushing method, which offers a lower technological barrier and reduced preparation costs, for the production of abrasive particles subsequently fabricating corundum stacked abrasives. Upon setting the binder composition to a molar ratio of n(SiO2):n(B2O3):n(Na2O) = 65:23:12, it was observed that the crystallization within the glass matrix was minimized and the optimal sintering temperature for the synthesized laminate abrasive to be sustained at 820 °C. At the aforementioned temperature, the binder melt is capable of flowing uniformly amongst the abrasive granules, thereby ensuring a robust encapsulation of the particles. The average single particle compressive strength of the prepared corundum stacked abrasive with a grain size of forty mesh can reach the highest of all composition points at 28.56 N and the average single particle compressive strength of the prepared diamond stacked abrasive is 28.14 N.
... Recently Zhi et al. [26] reported single alkali Na 2 O-CaO-B 2 O 3 -SiO 2 bio glasses on using waste egg shells and investigated effect of CaO on physical and mechanical properties. Shaaban et al. [27] [29] and examine in detail vitro study with increasing ZnO concentration and shown effective results for bone tissue applications. ...
... Abdelghany et al. [30] investigated the radiation shielding efficiency in copper oxide modified bio active glasses. There are some shielding properties reports also mentioned in the various glass systems based on the various glass systems containing boro sodium calcium compositions [21][22][23][24][25][26][27][28][29][30][31][32][33]. ...
The melt quenching technique was utilized to prepare a novel mixed alkali bioglass composition, denoted as 30B2O3–20SiO2–xNa2O–(20–x)Li2O–20CaO–10ZnO, where x = 0,5,10,and 20 and samples codes were BSCZ0, BSCZ5, BSCZ10, BSCZ15 and BSCZ20. The sample code of present samples indicate as BSCZ0 to The glass properties were evaluated using density, FTIR, and radiation shielding capacity, and the simulated body fluid (SBF) solution was prepared according to Kokubo’s method. The bio-activeness of the prepared glasses was confirmed by XRD and FTIR spectra, which exhibited crystalline peaks at various reflections due to the formation of calcite and hydroxyapatite layers on the glass surface. The FTIR spectra revealed the formation of hydroxyapatite layers after fourteen days of SBF treatment, as evidenced by the strong intensive peaks around 1020 cm⁻¹. The experimental density values vary between 3.1926 g/cc to 3.1605 g/cc. The glass density decreased with increasing Na2O content due to the decreasing number density correlated to the alkali content. To predict the glass density, an artificial intelligence density model was applied to the present glasses, which utilized 10,000 oxide glass samples. Among the different regression models tested, random forest regression produced the best R² value (0.917), followed by artificial neural network and polynomial regression. In the case of RFR the predicted density values varies from 3.1626 g/cc to 3.1305 g/cc which were closer values to the experimental density values. The radiation shielding properties of present glasses studied by Phy-X/PSD program and simulated by FLUKA code in the photon energy range of 0.015–15 MeV. Results show that there is a good agreement between the obtained results. BSCZ0, which was free of Na2O, exhibited the highest values of mass (µm) and linear (µ) attenuation coefficients compared to all other glasses, and the effective atomic number (Zeff) achieved the same trend as µm and µ. Sample BSCZ0 also exhibited the lowest values of half value layer (HVL) parameter at all incident photon energies.
... From the figure, the unheated and sample heat-treated at 600 °C show a broad hump shape indicating the amorphous glass in nature. The amorphous state of the glass at 600 °C started to transform to the crystalline state of the glass-ceramics at a temperature of 700 °C, which can be confirmed by the DSC results from the ref [21]. . When the sample was heat-treated from 700 °C to 900 °C, the formation of major crystalline phases is found as shown: Cuspidine (ICSD No.: 98-002-1508), Wollastonite (ICSD No.: 998-004-6164) and minor Zeolite phase (ICSD No.: 98-009-3690). ...
This research aims to investigate the potential of novel CaF2 − CaO − Na2O − B2O3−SiO2 glass systems and converted to bioactive glass-ceramics. The study involves examining the effects of different heat treatment temperatures and immersion periods, with the goal of exploring these materials as viable alternatives for various biomedical applications. A typical melt-quenching technique was used to synthesize the glass samples, followed by a controlled heat treatment. The main crystalline phases are cuspidine and wollastonite, which have the potential to promote bioactivity, especially in dental and bone-related applications. The sample heat-treated at 700 °C showed an increased microhardness and fracture toughness by more than 116% and 36%, compared to the initial value. Furthermore, the increase in pH and the observed weight loss/gain demonstrated the reactivity of the samples with the phosphate buffer-saline medium, indicating their bioactive properties. Remarkably, the microhardness and fracture toughness exhibited notable improvements after 14 days of immersion, with an enhancement of 4.71% and 4.66%, highlighting their potential durability and longevity in high-strength dental crown applications. Consequently, this research presents a promising method for developing sustainable novel glass and glass-ceramic materials devoid of phosphates. These materials boast enhanced mechanical properties while preserving bioactivity, making them well-suited for dental implants and restorative purposes.
... The reported Ca content in this work is considerably high compared to studies conducted on other oyster species or other sources (mussel and eggshell). One study reported 97 wt.% of Ca in C. gigas treated at 1 000 °C [30], while other studies found 98.22 wt.% of Ca for Saccostrea cucullata [31] and 97.74 wt.% for Ostrea plicatula [32]. Previous studies reported a Ca content of 87.2 wt.% in mussel shells [33] and 97.90 wt.% in eggshells measured by XRF [34]. ...
Citation: S.A. Rosli, M.H.Jameel, M.Z.H. Mayzan, et al. Simple thermal treatment of waste oyster (crassostrea belcheri) shells for the production of calcium minerals in biomaterials application. Nano Biomedicine and Engineering, 2024. Abstract The effect of the thermal treatment of waste oyster (Crassostrea belcheri) shells on different properties was explored. In this preliminary work, the waste oyster shells were collected from Muar River, Malaysia. All samples were cleaned, dried, and subjected to a simple heat treatment in air at 500-1 200 °C. All heat-treated samples were characterized to determine their mass loss, chemical composition, crystalline phase, surface morphology, and powder density properties. Changing the temperature from 500 to 1 200 °C increases the calcium (Ca) food content in oyster shells. Furthermore, the decomposition of calcium carbonate (CaCO 3) from 98.15 wt.% to 99.07 wt.% was completed at 682 °C with 45 wt.% mass loss in a controlled nitrogen environment. When heat treatment processes are conducted in air, only 14.74 wt.% mass loss is recorded. The X-ray diffraction results confirmed that CaCO 3 successfully transformed α peak (CaO 4) to γ peak and η peak (CaO) at an angle (θ) of 30° and at above 800 °C. The Fourier transform infrared (FTIR) Result revealed changes in functional groups as the temperature increased. The phase transformation and morphological analysis agree with measured powder density values from 2.63 to 2.30 g·cm −3. All these findings indicate that heated waste oyster shells are a potential source of calcium minerals and can be used for biomaterial products.
... To improve the mechanical properties of BaG, researchers have study the effect of CaF 2 /P 2 O 5 ratios on physical and mechanical properties of novel CaO-Na 2 O-B 2 O 3 -SiO 2 glasses [32]. BaG-F is bioactive, and it has high amounts of fluorine (CaF 2 ) intercalated with the quaternary system (SiO 2 -Na 2 O-CaO-P 2 O 5 ). ...
This work aimed to evaluate the influence of CaF2 addition in the bioactivity of the samples. The system 60B2O3-4P2O5-18Na2O-xCaF2-(18-xCaO), with x= 0, 5 and 10 wt% was synthetized by melt-quenching method. The in vitro bioactivity of the glasses was investigated by X-ray diffractogram (XRD), Raman, Fourier transform infrared spectroscopy (FTIR) and pH after immersion in SBF solution during 28 days. Results of pH presented an increase after 24 hours of soaking in SBF, which contributes to the dissolution of the external layer of the glass and precipitation of apatite. Hydroxyapatite and fluorapatite formation was confirmed by XRD patterns, Raman and FTIR spectra, confirming the bioactivity of the samples. Cytotoxicity tests were performed on osteoblastic cells. All the samples presented cytotoxicity smaller than 10%, and induced the osteoblast proliferation, indicating a good cytocompatibility and good cell viability. Therefore, the glasses have potential to be applied in biomedical applications, such as odontology and tissue engineering.
This work investigates the role of sintering temperature on bioactive glass-ceramics derived from the new composition CaO-P2O5-Na2O-B2O3-SiO2 glass system. The sintering behaviour of the samples' physical, structural, and mechanical properties is highlighted in this study. The experimental results indicated that the sintering process improved the crystallization and hardness of the final product. Results from XRD and FTIR showed the existence of carbonate apatite, pseudo-wollastonite, and wollastonite phases. From the results, the bioglass-ceramics sintered at 700 °C obtained the highest densification and optimum mechanical results. It had the value of 5.34 ± 0.21 GPa regarding microhardness and 2.99 ± 0.24 MPa m1/2 concerning fracture toughness, which falls in the range of the human enamel. Also, the sintered samples maintained their bioactivity and biodegradability after being tested in the PBS medium. The bioactivity does not affect but slows down the apatite formation rate. Overall results promoted the novel bioglass-ceramics as a candidate material for dental application.
In this work, the designed bioactive glass utilized waste is expected to improve mechanical properties while maintaining the bioactivity performance during the in-vitro assessment. Herein, the novel bioactive glasses were prepared using the melt-quenching approach. Phosphate buffer saline was used as an immersion medium during the in-vitro bioactivity and biodegradability evaluation to ascertain the glass's bioactivity characteristics. The XRD results indicated the carbonate apatite phase for sample 0F and the fluorapatite and calcite phase for sample 3F, supported by the FTIR spectra. Further, the pH increased from (7.437 ± 0.004) to (9.699 ± 0.058) for 0F and (9.635 ± 0.014) for 3F, indicating the samples' bioactivity in response to the immersion medium. In addition, 3F exhibited a higher hardness (3.29 ± 0.07 GPa) and toughness (2.4 ± 0.08 MPa m1/2), supported by the weight gained in the biodegradability analysis. This work offers a promising technique to fabricate the bioactive glass incorporating waste, adding fluoride content into the glass for potential dental application.
In this work, biocompatible glass (bioglass) particles were prepared by low temperature, acid catalysed sol-gel method. The effect of varying phosphate (P 2 O 5 ) content (10, 15 and 20 mol %) in the sol-gel derived glass composition were studied. The sol-gel derived bioglass particles were compacted into cylindrical pellets via hydraulic press machine and sintered at 600°C for 3 hours. The bioglass particulates were analysed by x-ray fluorescence (XRF), Fourier Transformed Infrared (FTIR), X-Ray Diffraction (XRD) and nitrogen gas adsorption. Meanwhile, the sintered bioglass pellets were analysed by FTIR, XRD and FESEM-EDX. Furthermore, in vitro bioactivity analysis was performed by immersion in simulated body fluid (SBF) for 14 days. Bioglass particulates with high glassy phase, high surface area and high porosities were obtained for all compositions. Increasing of phosphate content to 20 mol% particularly reduced the porous characteristics of the bioglass particulates. Furthermore, leads to higher bridging oxygen (BO) atoms, higher amorphous silicate networks, lower glass crystallinity and higher number of phosphate crystallites within the amorphous glassy matrix. Increased to 20 mol% of phosphate also reduced the ability of the bioglass surface to induce carbonated apatite formation when immersed in simulated body fluid (SBF) solution.
Dental caries and periodontal disease are responsible for the most frequent set of chronic diseases in humans, for which no perfectly regenerative solutions are available yet. As a result, materials combining an intrinsic antibacterial activity with tissue regeneration properties for minimally invasive dental therapies are in high demand. Here we report on the fabrication and characterization of a novel nanocomposite material for such dental applications. The material is composed of narrowly disperse Na2O–CaO–P2O5–SiO2 bioglass-ceramic nanoparticles, 30–70 nm in diameter, doped with antibacterial and osteogenic zinc and niobium ions, and hybridized with chitosan. These systems were characterized for their particle size, morphology, atomic and phase composition, and glass-ceramic/polymer interface with the use of transmission electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction and Fourier transform infrared spectroscopy. After annealing at 680 °C, amorphous silica in the bioglass-ceramic coexisted with silicalite-1 and combeite, the average crystallite size of which was 20–40 nm. In spite of the significantly better incorporation of zinc than of niobium inside the glass-ceramic network, zinc did not affect the particle size and shape distribution, while niobium lowered the average particle size. Chitosan increased the hydration capacity of the bioglass-ceramic and it formed a continuous interface around the bioglass-ceramic nanoparticles, devoid of micropores. This intimacy of the interface was confirmed by the downshift of the critical Si–O(–Si) vibration modes in the bioglass-ceramic upon hybridization with chitosan. The addition of zinc ions hampered the partial recrystallization during annealing by interfering with the Si–O network restructuring, in direct proportion with its concentration. Niobium ions produced a similar structure-breaking effect, which was evidenced, as in the case of zinc, by upshifting the antisymmetric Si–O–Si stretch of the bridging oxygen and increasing the full-width at half maxima for all the major Si–O(–Si) vibration modes. The effective electrostatic attraction between the aminated hydrocarbon chains of chitosan and the negatively charged silanol groups of silica may extend to the interaction with dentin collagen fibrils decalcified due to caries, making the material of potential interest for adhesive fillers of cariogenic lesions in teeth. Both the undoped and the doped bioactive glass-ceramics interacted favorably with odontoblast-like cells, accentuating their potential for further research for applications in minimally invasive reparative dentistry.
Lead and cadmium are amongst some of the most hazardous and carcinogenic heavy metals to contaminate water sources in the industrial sector. As such, there have been several research efforts to remediate this worldwide environmental concern. The main objective of this study was to determine the efficacy of using two natural agricultural waste materials, sugarcane bagasse and eggshells, in removing Pb (II) and Cd (II) from aqueous solutions. The biosorbents were characterized using Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD). The functional groups present in eggshells was carboxylic and carbonyl groups with hydroxyl and carbonyl groups present for bagasse. Crystallographic information revealed both an amorphous and a crystalline phase for bagasse with a crystalline phase for eggshells. The effect of particle size and pH was investigated where a higher removal rate was obtained with increasing pH with no significant difference observed with the particle size. Sorption equilibrium and kinetics were also studied by varying the initial concentration and contact time, respectively. The Langmuir and Freundlich models were applied for the mathematical description of the isotherms. The applicability of the Langmuir isotherm implied a monolayer formation of metal ions onto the surface of the adsorbents. The maximum amounts of Pb and Cd adsorbed based on 1 g of biosorbent were found to be 277.8 and 13.62 mg/g for eggshells and 31.45 and 19.49 mg/g for bagasse, respectively. The pseudo-second order model was used to describe the kinetics of the adsorption process for Pb and Cd ions. Based on the above findings, this study has demonstrated the efficacy of both adsorbents and presents it as a viable adsorbent for the biosorption process.
Bioactive novel glasses of chemical composition xAg2O-20Li2O-25TeO2-(55-x) B2O3 (0 ≤ x ≤ 2 mol%) were synthesized through the melt-quench method and investigated the influence of Ag2O on various properties. The antibacterial properties of the obtained glasses were studied against two gram negative bacterial strains like Salmonella and E. Coli. (E. Coli.) species and the antibacterial zone of inhibition was increased with increasing Ag2O. The density (ρ) of the glasses increased from 3.60 to 3.83 g/cm³ with the addition of Ag2O. UV–Vis. absorption spectrum of the glass system was recorded and estimated the cut-off wavelength (λc), the optical band gap energies (Eopt), the Urbach energy (ΔE), the refractive index etc. FT-IR and Raman spectroscopic studies revealed the existence and impact of the modifier Ag2O. Impedance study revealed that the NBOs play significant role in the enhancement of the ionic conductivity and also causing the enhancement of antibacterial efficiency.
The prosthetic materials used in dentistry can generally be classified into different categories as measurement, restorative, cements and soft liner materials. Different tests are used in the measurement of the resistance and surface properties of these materials. The aim of this study was to given information about mechanical properties of materials, mechanical tests, test are used evaluated the surface hardness and roughness.
Mechanical tests involve shear, micro-shear, tensile, micro-tensile, shear-tensile, torsion, compression, fatigue strength and flexure tests. Hardness tests are Brinell, Vickers, Knoop, Rockwell, Shore A and Barcol tests. Surface roughness tests are conducted using profilometers, scanner electron microscope and atomic force microscope. In addition, the internal structure of the materials is also tested by doing absorption and coloring tests.
With the mechanical tests, the durability of the materials under the chewing pressure is measured, and with the surface roughness tests, measures are taken for the irritation of the oral tissues. Various in vitro tests are required to evaluate the materials used in the oral environment.
The alumino-silicate-fluoride (ASF) bioglass system with empirical formula [(45-x)SiO2-xCaF2-20P2O5-20Al2O3-15CaO] where x = 5, 10, 15, and 20 (wt.%) has been synthesised by using conventional melt-quenching method. In this study, soda lime silica (SLS) glass and clam shell (CS) vitreous waste were utilized as a source of silicon dioxide (SiO2) and calcium oxide (CaO), respectively. The different physical behaviors of ASF bioglass were closely related to the CaF2 content in each composition. The structural analysis shows the presence of various chemical bonds showing the formation of ASF bioglass. The ASF bioglass has many applications in dental field and efforts to improve its formulation can promise a better future in medical procedures.
In this review, we first briefly introduce the general knowledge of glass-ceramics, including the discovery and development, the application, the microstructure, and the manufacturing of glass-ceramics. Second, the review presents a detailed description of glass-ceramics in dentistry. In this part, the history, property requirements, and manufacturing techniques of dental glass-ceramics are reviewed. The review provided a brief description of the most prevalent clinically used examples of dental glass-ceramics, namely, mica, leucite, and lithium disilicate glass-ceramics. In addition, we also introduce the newly developed ZrO2-SiO2 nanocrystalline glass-ceramics that show great potential as a new generation of dental glass-ceramics. Traditional strengthening mechanisms of glass-ceramics, including interlocking, ZrO2-reinforced, and thermal residual stress effects, are discussed. Finally, a perspective and outlook for future directions in developing new dental glass-ceramics is provided to offer inspiration to the dental materials community.
This research involved comprehensive studies on thermal, physical, and
morphological properties of SiO2-Na2O-CaO-P2O5 (SNCP) glass-ceramic at
various sintering temperatures. The study in SNCP glass-ceramic using
soda-lime-silica (SLS) wastes glass and clam shell (CS) wastes as the main
raw of materials via conventional melt-quenching technique and solid state
sintering are interesting and challenging by considering the research using
waste materials to fabricate novel SNCP glass-ceramic. The main peaks,
Na3PO4 and Ca3Na6Si6O18 were assigned to high crystallization temperature
(Tc) at 650-950°C. The density of samples increases at 550-750°C and
decreases at 850-950°C due to the increase of sample thickness and higher
specific volume at high sintering temperature. FESEM micrograph showed that
existed porous increased at sintering temperature 850-950°C contributes
effect to low densification of the sample.
The objective of this study was to investigate the effect of magnesium (1 wt%) and aluminum (1 wt%) incorporation on the in vitro bioactivity and biodegradation behavior of 45S5 bioactive glasses synthesized from rice husk biogenic silica. The performance of biogenic silica-based samples was compared well with commercial silica-based counterparts. The in vitro biodegradation behavior of bioactive glasses was evaluated by the weight loss of samples and pH variation in the Tris buffer solution. Based on composition, bioglasses possessed different properties before and after simulated body fluid (SBF) immersion. The incorporation of magnesium (Mg) and aluminum (Al) enhanced the Vickers hardness of bioglasses. All the bioglasses showed the hydroxyapatite layer formation after SBF treatment as confirmed by the dissolution, FTIR, SEM and XRD analysis, however it was more prominent in the rice husk silica-based 45S5 bioglass. The biogenic silica seems to be a promising starting material for bioglass systems to be used in bone tissue engineering applications.
At present, researchers in the field of biomaterials are focusing on the oral hard and soft tissue engineering with bioactive ingredients by activating body immune cells or different proteins of the body. By doing this natural ground substance, tissue component and long-lasting tissues grow. One of the current biomaterials is known as bioactive glass (BAG). The bioactive properties make BAG applicable to several clinical applications involving the regeneration of hard tissues in medicine and dentistry. In dentistry, its uses include dental restorative materials, mineralizing agents, as a coating material for dental implants, pulp capping, root canal treatment, and air-abrasion, and in medicine it has its applications from orthopedics to soft-tissue restoration. This review aims to provide an overview of promising and current uses of bioactive glasses in dentistry.
Abundance of eggshell waste leads to high generation of solid waste as it is difficult to decompose. Besides, eggshell waste has no economic value and most of the waste is dumped in landfills without any pretreatment. Thus, an efficient method has been conducted to study the chemical characterization of eggshell waste. Eggshells contain potential useful minerals such as calcium oxide (CaO) that can be derived from calcium carbonate (CaCO3) in the eggshells. The objective of this study is to synthesize and characterize CaO from eggshells. Raw eggshells are analyzed by thermal gravimetric analyzer (TGA). Then, they are calcined at the temperature of 900oC for 1 hour with nitrogen gas. Raw and calcined eggshell are characterized by x-ray fluorescence (XRF)and Fourier transform infrared (FTIR) spectroscopy to obtain elemental composition and functional group of eggshell. TGA showed that the suitable temperature for calcination was 900oC. XRF results showed that CaO in raw eggshell was 98.50% and increased to 98.56% in calcined eggshell. FTIR analysis of eggshell showed the Ca – O band formed around 670 cm-1.CaO from eggshell is expected to act as a catalyst for bio-oil production.
Through the traditional approach of the melt-water quenching technique, it is seen that Alumino-Silicate-Fluoride (ASF) bioglass system is assembled. Through the very investigation of this paper, it is noted that preparation of ASF bioglass is composed of Clam Shells (CS), Soda Lime Silicate (SLS), CaF2, P2O5, and Al2O3 with the empirical formula [xCS⋅(45 − x)SLS⋅15CaF2⋅20P2O5⋅20Al2O3] where x= 5, 10, 15 and 20 (wt%). The waste materials used to produce ASF bioglass were CS and SLS. The physical and structural properties of bioglass are obtained through Energy X-ray (EDX), density (ρ), molar volume (Vm), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) and Field Emission Scanning Electron Microscopy (FESEM) spectroscopy. Such measured physical parameters like density and molar volume were found to vary linearly with increasing the CaO content in the bioglass composition. X-ray powder diffractrogram showed that the ASF bioglass samples with higher amount of CaO content are in amorphous phase, but a small and sharp peak crystal phase was observed and known as fluorapatite (Ca5(PO4)3F). Meanwhile, FTIR spectroscopy revealed various bonds such as Si–O–Si, P–O–P, C–O and O–H, indicated to the formation of ASF bioglass before sintering occurred. FESEM analysis showed non-uniform particle distribution, irregular in shape and random grain size of the bioglass. Although this type of bioglass is well established for dental application, its effect on waste materials such as CS and SLS for used in dental field has not been extensively studied. Revealed various bonds, stretching and bending vibrations within the samples before sintering occurred.
Objective:
Dental materials that release calcium, phosphate and fluoride ions could prevent demineralisation and/or enhance remineralisation of enamel. The objective was to develop a novel bioactive glass (BAG) resin and investigate pH changes and ion release in 3 immersion media.
Methods:
Quench melt derived BAG (35.25% SiO2, 6% Na2O, 43% CaO, 5.75% P2O5, and 10% CaF2) was incorporated into a resin (42.25% BisEMA, 55% TEGDMA, 0.25% DMAEM, 0.5% camphorquinone and 2% 4-Meta), with a filler load of 80% by weight. Ninety composite disks for each BAG loading of 80%, 60%, 50%, 40%, 20%, and 0% were made and each disk was immersed in 10ml of either tris buffer (TB), or artificial saliva at pH=7 (AS7) or pH=4 (AS4), n=30 for each solution. Three disks of each loading were taken from each of the solutions, at ten time points (6h-6months), for measurement of pH, fluoride, calcium and phosphate.
Results:
The BAG adhesive raised the pH in all the solutions, release Ca, PO4 and F ions especially in AS4. The rise in pH and the release of Ca and F are directly related to the BAG loading and the time of immersion. The pH and the ion releases were maintained and continued over 6months.
Significance:
Unlike glass ionomer resins, favourable ions F, Ca and PO4 releases were maintained over a long time period especially in acidic condition for this novel BAG-resin composite. This indicates the resin has the potential to prevent formation and progression of early caries lesions.
Glass ionomer cement (GIC) is an important restorative dental biomaterial which is utilized in filling, lining and adhesion restoration. The aim of this work is the enhancement of the mechanical, morphological, antibacterial and fluoride release properties of the glass ionomer cement by incorporation of different wt% of nano hydroxyapatite powder (HA). The result of this work refers to that, the addition of nano-HA to GIC enhance its fluoride ion release, compressive strength and antibacterial effect against Streptococcus mutans and the bacterial inhibition zone reached to about 8.6. mm when 8% HA wt% is used. This suggests that addition of nano-HA particles to GIC to produce GIC-HA hybrids which can be used as suitable materials for improving its fluoride ion release, mechanical properties and inhibiting residual bacteria in dentine. © 2018 Brazilian Metallurgical, Materials and Mining Association.
Three new silica-based glass formulations with low molar Ca/P ratio (2-3) have been synthesized. The thermal properties, the crystalline phases induced by thermal treatments and the sintering ability of each glass formulation have been investigated by simultaneous differential scanning calorimetry-thermogravimetric analysis (DSC-TG), X-ray diffraction (XRD) and hot stage microscopy (HSM). The glasses exhibited a good sintering behavior, with two samples achieving shrinkage of 85%-95% prior to crystallization. The bioactivity of the glasses in simulated body fluid (SBF) has been investigated by performing XRD and Fourier transform infrared spectroscopy (FTIR) on the samples prior and after immersion. The glasses with lower MgO contents were able to form a fully crystallized apatite layer after three days of immersion in simulated body fluid (SBF), while for the glass exhibiting a higher MgO content in its composition, the crystallization of the Ca-P layer was achieved after seven days. The conjugation of these properties opens new insights on the synthesis of highly bioactive and mechanically strong prosthetic materials.
A conventional melt quenching technique was used to successfully fabricate Mn2O3 -doped willemite glass-ceramics (Zn2SiO4:Mn3+) produced from the ZnO-SLS glasses. The results from XRD revealed that willemite crystallization is improved by increasing the sintering duration. It was revealed that, as the sintering duration progressed, the phase formation shifted from amorphous to α-Zn2SiO4 crystal. In addition, the structural growth of willemite phases can be seen using FTIR spectroscopy. The results of UV-Vis spectroscopy indicated that the intense absorption occurs in the UV zone, with wavelengths ranging from 250 nm to 400 nm, while the optical band gap showed a decreasing trend from 3.61 eV to 2.52 eV. These results perfectly established that Mn3+ dopant is potentially beneficial for producing willemite glass-ceramics for optoelectronic applications.
Ionizing radiation interaction might occur during diagnostic imaging and radiotherapy procedures. It has been reported that gamma-ray radiation can damage the living cells through the energy transfer. Therefore, investigation the ionization radiation attenuation properties of biomaterials have a crucial importance. In the current study, tungsten disulphide (WS2) nanopowder-containing borate-based bioactive glass composites were prepared. Their physical, structural, mechanical and ionization radiation attenuation properties were investigated in detail. Monte Carlo simulations and radiation attenuation properties were studied through MCNPX and Phy-X/PSD. Results showed that sintering performed at 575 °C for 1 h in air atmosphere caused formation of some tungsten trioxide in the structure. Addition of WS2 nanopowders increased the bulk density and improved the mechanical properties of the prepared bioactive glass composites. Simulation studies revealed the influence of WS2 content on reduction the build-up factors and enhancement of the photon attenuation ability for all the considered photon energies.
Municipal solid waste incinerated (MSWI) fly ash contains heavy metals and chloride, which is urgent to be disposed via an effective method. Herein, glass–ceramics, one of the recycling waste materials based on MSWI fly ash with high chloride content, have been developed from one-step process. MSWI fly ash and waste glass have been utilized as calcium and silicon sources, respectively. Glass–ceramics were successfully prepared by the one-step process. It is found that the increase in MSWI fly ash promotes the fracture of glass mesh (Si–O) and the generation of non-bridging oxygen, reducing the polymerization degree of glass network structure, which leads to the decrease in glass stability. The difference between glass transition temperature (Tg) and crystallization temperature (Tc) was narrowed, and crystallization activation energy of basic glass was reduced, which promoted crystallization. With lower crystallization activation energy (E = 217.56 kJ·mol−1) and high utilization rate of 50 wt% MSWI fly ash, the optimal glass–ceramics with spherical diopside, cuspidine and glass phase, excellent hardness of 7.97 GPa and bending resistance of 114.86 MPa are achieved. It is worth mentioning that most of the high content of chlorine in MSWI fly ash will evaporate during vitrification process; the residual chlorine as well as heavy metals can be present steadily in crystalline grains. Therefore, this study not only increases the attachment value of MSWI fly ash, but also eliminates the problems caused by high chlorine and heavy metals in MSWI fly ash.Graphic abstract
This paper reports on the synthesis and characterization of original sodium calcium silicate glass, with CaF2 as a nucleating agent, along with the successful transformation of the as-made matrix into glass-ceramic. Characteristic temperatures of thermal events were investigated by Differential Thermal Analysis. Volumetric density, refractive index, molar volume, and electronic polarizability of the newly developed glasses were determined and discussed as a function of Ca(O/F2) and Na2O content, fixing glass former SiO2 at 50 mol%. Transmittance and optical band gap energy were evaluated. Network structure was studied through Raman spectroscopy and X-Ray diffraction. Moreover, Eu3+ was used as a local structural probe in equivalent Eu2O3-doped samples. Luminescence properties (emission spectra and transition lifetimes) allowed us to investigate the local environment of precursor glass and glass-ceramic. Calcium fluoride nanostructured glass-ceramic, with 20 nm-sized crystals, was obtained with significant transparency (60-70 % in VIS region). The refractive index of synthesized glasses was too close to that of precepted crystals, which is the requisite for high transmittance. The decay time of Eu3+ ions embedded into the matrix has shown that the glass-ceramics environment’s phonon energy is lower than in as-made glass, making this matrix an excellent candidate for photonics applications.
This work studied the crystallization process of two bioglass series derived from 45S5® containing niobium (BGNb5 and BGNb10). In vitro biological analyzes of cell viability corroborate with the qualitative interpretation of the NC values, of a open and fragmented structure, which is interesting from a biological point of view and with the FTIR and Raman results which demonstrated that the breakdown of Si-O-Si bonds and the formation of Si-O-NBO bonds play an important role in the interface of the biological responses of the bioactive materials. X-ray diffraction (XRD) and Differential scanning calorimetry analysis (DSC) also generated insight into the structure of the glasses. To the best of our knowledge, this seems to be the first time that structural changes in bioactive glasses derived from 45S5 resulting from the addition of niobium are studied during its crystallization process.
The present work reports on the synthesis and biocompatibility of SiO 2-P 2 O 5-MgO-CaO-SrO glass system. The MgO was partially replaced by the SrO to check its influence on the bioactivity of the glass samples. The silica used for the development of glass samples was obtained from rice husk ash using acid-base precipitation technique. The structural, morphological and thermal properties of the synthesized glasses are characterized by X-Ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and differential thermal analysis (DTA) techniques. The bioactivity of the glasses was monitored by surface activity of the glass samples after treatment with the simulated body fluid (SBF). The evolution of the apatite layer was confirmed by observing variations in the crystal structures, morphological features, and evolution of new functional groups. The release of the ions in the SBF solution was examined by microwave plasma atomic emission spec-troscopy (MP-AES). Evolution of the hydroxyapatite (HAp) layer was also examined by optical-analytic approach. Further the drug loading efficiency was measured using VANCO as model drug. The incorporation of SrO led to enhancement in the bioactivity of the glass samples as compared to the one without it.
This paper investigates a new microcalorimetric approach to assess the capacity of bioactive glasses, to form hydroxyapatite during immersion in physiological fluids. Three silicate glasses were selected namely 45S5 (46.1SiO2-2.6P2O5-26.9CaO-24.4Na2O; mol%), F0 (46.1SiO2-2.6P2O5-37.6CaO-6.8Na2O-6.8K2O; mol%), and F3 (44.8SiO2-2.5P2O5-36.5CaO-6.6Na2O-6.6K2O-3.0CaF2; mol%), synthesized by a melt-quench route and studied initially using electron microscopy. The hydroxyapatite formation of samples immersed in simulated body fluid (SBF) was monitored using X-ray diffraction and Infrared spectroscopy. The microcalorimetric investigations were conducted by observing, over seven days, the thermochemical behavior of glasses in SBF at 37°C and by measuring the heat of acidic dissolution of treated and untreated samples in SBF. The results showed that the samples with the higher capacity to form apatites also present the higher heat variation from day-today , with 45S5 presenting the highest heat difference recorded in both experiments. These analyses led to the quantification of the calcium phosphate formed for each bioactive glass composition.
Background
Owing to increased egg consumption globally, a corresponding surge of about 18% in egg production has been recorded during the last decade as reported by WATT Global Media's Executive Guide to World Poultry Trends. Up till 2017, global egg production has hit 80-million metric-ton mark with China, USA and India, being the leading egg-producing countries contributing their share of 458, 109 and 95 billion eggs per annum, respectively. Global egg production for the year 2018 was 78 million metric tons, contributing approximately 8.58 million metric ton of eggshells which are being discarded mostly as waste. This calcium-rich commodity is dumped into landfills, leading to various environmental issues, and therefore should be tackled properly.
Scope and approach
Eggshells are obtained from egg processing plants, egg stations, chicken hatcheries, industries and homes in millions of tonnes and can be employed in a myriad of fields. The following review article provides a brief insight into various applications of eggshells in our society, such as their use in medicinal supplements, bone graft substitute and denture base. Eggshells can also be employed in constructing floor tiles and in cement to enhance compressive strength. Other diverse applications of eggshell may include animal feed, plant fertiliser, batteries, inkjet printers, biodiesel production and removal of heavy metals from soil and water.
Key findings and conclusion
The increasing urbanisation and industrialization with amplified waste generation have wreaked havoc on our climate; thus, making it necessary to take certain extravagant measures to ensure the safety and sustainability of our planet.
This paper reports on synthesis and characterization (sintering, crystallization, microstructure and mechanical properties) of novel alumina-containing (1 mol%) bioactive glass-ceramics (GCs) in CaO-MgO-SiO2 system with additives of K2O, Na2O, P2O5, CaF2, and Al2O3. Dense and well-sintered GCs were produced by glass-melt quenching and glass-powder compact sintering. The K-free GCs were comprised of diopside, wollastonite, and fluorapatite, and the K-containing ones consisted of diopside, fluorapatite, and alpha-potassium magnesium silicate (α-PMS). The mechanical properties of the produced GCs were better than those of the titanium and zirconia dental implant materials, and their modulus of elasticity (27 - 34 GPa), microhardness (6.0 - 6.7 GPa), and fracture toughness (2.1 - 2.6 MPa⋅ m0.5) are a good match to those of human jaw bone and dentine. The produced GCs were also bioactive, which was witnessed by the formation of hydroxyapatite on their surface after their immersion in simulated body fluid at 37 °C.
Objective
In the context of minimally invasive dentistry and tissue conservation, bioactive products are valuable. The aim of this review was to identify, clarify, and classify the methodologies used to quantify the bioactive glasses bioactivity.
Methods
Specific search strategies were performed in electronic databases: PubMed, Embase, Cochrane Library, and Scopus. Papers were selected after a review of their title, abstract, and full text. The following data were then examined for final selection: BAG investigated, objectives, criteria, methods, and outcomes.
Results
Sixty studies published from 2001 to 2019, were included. The bioactivity of BAG can be evaluated in vitro in contact with solutions, enamel, dentin, or cells. Other studies have conducted in vivo evaluation by BAG contact with dentin and dental pulp. Studies have used various analysis techniques: evaluation of apatite with or without characterization or assessment of mechanical properties. Reprecipitation mechanisms and pulp cell stimulation are treated together through the term ‘bioactivity’.
Significance
Based on these results, we suggested a classification of methodologies for a better understanding of the bioactive properties of BAG. According to all in vitro studies, BAG appear to be bioactive materials. No consensus has been reached on the results of in vivo studies, and no comparison has been conducted between protocols to assess the bioactivity of other bioactive competitor products.
In the present study, the effects of Sr and Mg were investigated on mechanical and biological properties of 58S bioactive glass (BG). SiO2-P2O5-CaO BG with different contents of Sr and Mg were synthesized via the sol-gel method and immersed in simulated body fluid (SBF) for several days to explore their biocompatibility. Precise analyses of the BG using X-ray powder diffraction, scanning electron microscopy, and transmission electron microscopy showed that the Mg-doped BG containing 8 wt. % MgO possessed better biocompatibility. It was also found that mechanical properties of the BG could be improved by increasing the amounts of MgO and SrO. Both 5Sr-BG and 8Mg-BG samples did not exhibit any cytotoxicity while showing high alkaline phosphatase activity in comparison with control specimens. However, the Sr-doped BG sample including 5 wt. % SrO demonstrated enhanced bioactivity and biocompatibility.
Elevation of bone fluoride levels due to drinking beverages with high fluoride content or other means such as inhalation can result in skeletal fluorosis and lead to increased joint pain, skeletal deformities, and fracture. Because skeletal fluorosis alters bone's mineral composition, it is likely to affect bone's tissue-level mechanical properties with consequent effects on whole bone mechanical behavior. To investigate this, we determined whether incubation with in vitro sodium fluoride (NaF) altered bone's mechanical behavior at both the tissue- and whole bone-levels using cyclic reference point indentation (cRPI) and traditional 3-point bending, respectively. Forty-two ulnas from female adult rats (5–6 months) were randomly divided into 5 groups (vehicle, 0.05 M NaF, 0.25 M NaF, 0.75 M NaF, and 1.5 M NaF). Bones were washed in a detergent solution to remove organic barriers to ion exchange and incubated in respective treatment solutions (12 h, 23 °C). Cortical tissue mineral density (TMD) and geometry at the mid-diaphysis were determined by microCT. cRPI was performed on the distal diaphysis (9 N, 2 Hz, 10 cycles), and then bones were tested in 3-point bending to assess whole bone mechanical properties. The incubations in vehicle (0 M) up to 1.5 M in vitro NaF concentrations achieved bone fluoride levels ranging from approximately 0.70 to 15.8 ppm. NaF-incubated bones had significantly greater indentation distances, higher displacement-to-maximum force, and lower estimated elastic modulus, ultimate stress, and bending rigidity with increasing NaF concentration compared to vehicle-incubated bones. cRPI variables were moderately correlated to whole bone mechanical properties such that higher indentation distances were associated with lower estimated elastic modulus, ultimate stress, and bending rigidity. In conclusion, in vitro NaF incubation mostly has a deleterious effect on bone mechanical behavior with increasing NaF levels that is independent of bone turnover and reflected, in part, by less resistance of the tissue to cRPI-based indentation.
The present work focuses on the synthesis and structural elucidation of fluoride containing bioactive glasses in the system (in mol%) given by (53.86) SiO2 – (22.65) Na2O – (21.77-x) CaO – (1.72) P2O5 – x CaF2, where, x = 0, 5.44, 10.885 and 16.33. The role of the incorporated fluoride and its distribution within the glass were interpreted and analyzed using Molecular dynamics (MD) simulations and the results were compared with the modified random network (MRN) model. The interpretations from the model have been verified using the MAS-NMR spectroscopy technique. According to this model, fluoride containing bioactive glasses have been proposed to consist of silicate rich network regions and modifier cation – fluoride rich inter-network regions. The interface region was found to consist of non-bridging oxygen species (NBO) and phosphate cations which are either isolated orthophosphates (Q⁰P) or bridged with silicates in the form of pyrophosphate (Q¹P) units forming Si–O–P bonds. The gradual substitution of CaF2 for CaO in the base glass resulted in an increase in the silicate network connectivity with a reduction in the NBOs and lead to an increase in the association of modifier cations with fluoride ions. However, fluoride ions were found to show a marginal preference to associate with Na⁺ cations leading to a decrease in the association of Na⁺ ions with orthophosphate and silicate units. These overall structural findings were correlated with the in vitro ion dissolution behaviour of the bioactive glasses as well as with the thermal properties. The glasses were tested for their in vitro cell viability towards mouse osteoblast type (MC3T3) cells in which fluoride containing bioactive glasses did not show any toxicity and exhibited better cell proliferation. The antibacterial efficacy of the fluoride containing glasses was tested at various concentrations (5, 10 and 20 mg/ml) in E.coli bacterial inoculum in which bactericidal action was evidenced.
The waste-to-wealth concept aims to promote a future sustainable lifestyle where waste valorization is seen not only for its intrinsic benefits to the environment but also to develop new technologies, livelihoods and jobs.
The repair and restoration of bone defects in orthopaedic and dental surgery remains a major challenge despite advances in surgical procedures and post-operative treatments. Bioactive glasses, ceramics, glass-ceramics and composites show considerable potential for such applications as they can promote bone tissue regeneration. This paper presents an overview of the mechanical properties of various bioactive materials, which have the potential for bone regeneration. It also identifies current strategies for improving the mechanical properties of these novel materials, as these are rarely ideal as direct replacements for human bone. For this reason bioactive organic-inorganic composites and hybrids that have tailorable mechanical properties are of particular interest. The inorganic component (bioactive glass, ceramic or glass-ceramic) can provide both strength and bioactivity, while the organic component can add structural reinforcement, toughness and processability. Another topic presented in this paper includes 3D porous scaffolds that act as a template for cell attachment, proliferation and bone growth. Mechanical limitations of existing glass and ceramic scaffolds are discussed, along with the relevant challenges and strategies for further improvement. Advantages and disadvantages of different bioactive materials are critically examined. This paper is focused on optimization of biomaterials properties, in particular mechanical properties and bioactivity.
In this article, bioactive glass nanoparticles (BG-NPs) doped with boron were synthesized and characterized to evaluate their effects on human dental pulp stem cells (hDPSCs). All synthesized BGs were nano-sized and amorphous in nature. They showed the expected characteristic functional groups and composition close to the designed ones by microstructural characterizations. Porositimetry analysis revealed that increase of boron in the BG composition caused a decrease in the specific surface area, average pore diameter and total pore volume of NPs. hDPSCs were isolated from third molar teeth of patients and were shown to have the characteristics of mesenchymal stem cells. Dose dependent cytotoxicity study of boron doped BG-NPs suggested that 6.25 mg/ml was the optimum concentration for cells. ALP activity tests and intracellular calcium measurements revealed enhanced early stage odontogenic differentiation of hDPSCs treated with 6.25 mg/ml of different BG groups. Immunocytochemical staining showed positive effect of boron doped BG-NPs on DSPP, osteopontin and collagen I markers expression of hDPSCs. Our results indicated that boron doped BG-NPs hold potential as biomaterial in regenerative dentistry.
The global market for dental materials is predicted to exceed 10 billion dollars by 2020. The main drivers for this growth are easing the workflow of dentists and increasing the comfort of patients. Therefore, remarkable research projects have been conducted and are currently underway to develop improved or new dental materials with enhanced properties or that can be processed using advanced technologies, such as CAD/CAM or 3D printing. Among these materials, zirconia, glass or polymer-infiltrated ceramics, and glass-ceramics (GCs) are of great importance. Dental glass-ceramics are highly attractive because they are easy to process and have outstanding esthetics, translucency, low thermal conductivity, high strength, chemical durability, biocompatibility, wear resistance, and hardness similar to that of natural teeth, and, in certain cases, these materials are bioactive. In this review article, we divide dental GCs into the following two groups: restorative and bioactive. Most restorative dental glass-ceramics (RDGCs) are inert and biocompatible and are used in the restoration and reconstruction of teeth. Bioactive dental glass-ceramics (BDGCs) display bone-bonding ability and stimulate positive biological reactions at the material/tissue interface. BDGCs are suggested for dentin hypersensitivity treatment, implant coating, bone regeneration and periodontal therapy. Throughout this paper, we elaborate on the history, processing, properties and applications of RDGCs and BDGCs. We also report on selected papers that address promising types of dental glass-ceramics. Finally, we include trends and guidance on relevant open issues and research possibilities. This article is protected by copyright. All rights reserved.
The partial substitution of CaF2 for CaO in the Na2O–CaO–SiO2–P2O5 system was conducted by the sol–gel method and a comparison of the glass–ceramic properties was reported. Based on thermogravimetric and differential thermal analysis, the gels were sintered with a suitable heat treatment procedure. The glass–ceramic properties were characterized by X-ray diffraction, fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectrometer and so on, and the bioactivity of the glass–ceramic was evaluated by in vitro assays in simulated body fluid. Results indicate that with the partial substitution of CaF2 for CaO in glass composition, the volume density, apparent porosity, bending strength and microhardness of the glass–ceramics have been significantly improved. Furthermore, CaF2 promotes glass crystallization which does not inhibit the glass–ceramic bioactivity.
The effects of replacement of P2O5 by SiO2, on the crystallization behaviour, mechanical properties and bioactivity of glass-ceramics in the MgO–CaO–SiO2–P2O5 system were investigated. By decreasing P2O5 and increasing SiO2, the apatite crystallization peaks disappeared from DTA traces, whereas the wollastonite peaks remained unchanged. XRD results showed that by decreasing P2O5 and increasing SiO2 contents, the amount of apatite and wollastonite phases were decreased and increased, respectively. The diametral compression strength (DSC) and indentation fracture toughness (IFT) values gradually raised with increasing wollastonite content. The best results obtained for the specimens with the maximum amount of wollastonite were 36.6 and 2.74 MPa m1/2 for DCS and IFT, respectively. The bioactivity of specimens after being soaked in a simulated body fluid for one month were examined by SEM/EDX and FT–IR. A thin apatite layer was formed even on the surface of specimens containing the minimum amount of apatite phase.
Historically the function of biomaterials has been to replace diseased or damaged tissues. First generation biomaterials were selected to be as bio-inert as possible and thereby minimize formation of scar tissue at the interface with host tissues. Bioactive glasses were discovered in 1969 and provided for the first time an alternative; second generation, interfacial bonding of an implant with host tissues. Tissue regeneration and repair using the gene activation properties of Bioglass provide a third generation of biomaterials. This article reviews the 40 year history of the development of bioactive glasses, with emphasis on the first composition, 45S5 Bioglass, that has been in clinical use since 1985. The steps of discovery, characterization, in vivo and in vitro evaluation, clinical studies and product development are summarized along with the technology transfer processes.
Low-temperature mineralization sintering process for fabrication of fluoridated hydroxyapatite-containing bioactive glass
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