Cement Glass Research Articles

Investigation on Effect of Varying Weight Percentage of Glass Fiber and Filler on the Properties of Glass Fiber-Cement- Polyester Composites

In this research, the results of different weight percentage of glass fiber (30, 40 & 50), cement (0, 3 & 6) and polyester resin (70, 60 & 50), on the properties of glass fiber-cement-polyester composites are investigated. The specimens are prepared by hand lay-up technique. All the specimens are tested for tensile and flexural strength as per ASTM standards. Results showed that escalation in glass fiber wt.% improved the tensile strength (by 9% at 40 wt.% and 17% at 50 wt.%) and flexural strength (by 10% at 40 wt.% and 16.5% at 50 wt.%). Whereas an increase in cement weight percentage decreases tensile strength and increases flexural strength. The failure of the sample is due to glass fiber pull out and rupture of the matrix, under tensile load.

Strontium modulates osteogenic activity of bone cement composed of bioactive borosilicate glass particles by activating Wnt/β-catenin signaling pathway

There is a need for synthetic grafts to reconstruct large bone defects using minimal invasive surgery. Our previous study showed that incorporation of Sr into bioactive borate glass cement enhanced the osteogenic capacity in vivo. However, the amount of Sr in the cement to provide an optimal combination of physicochemical properties and capacity to stimulate bone regeneration and the underlying molecular mechanism of this stimulation is yet to be determined. In this study, bone cements composed of bioactive borosilicate glass particles substituted with varying amounts of Sr (0 mol% to 12 mol% SrO) were created and evaluated in vitro and in vivo. The setting time of the cement increased with Sr substitution of the glass. Upon immersion in PBS, the cement degraded and converted more slowly to HA (hydroxyapatite) with increasing Sr substitution. The released Sr2+ modulated the proliferation, differentiation, and mineralization of hBMSCs (human bone marrow mesenchymal stem cells) in vitro. Osteogenic characteristics were optimally enhanced with cement (designated BG6Sr) composed of particles substituted with 6mol% SrO. When implanted in rabbit femoral condyle defects, BG6Sr cement supported better peri-implant bone formation and bone-implant contact, comparing to cements substituted with 0mol% or 9mol% SrO. The underlying mechanism is involved in the activation of Wnt/β-catenin signaling pathway in osteogenic differentiation of hBMSCs. These results indicate that BG6Sr cement has a promising combination of physicochemical properties and biological performance for minimally invasive healing of bone defects.

Clinical Evaluation of the Retention of Resin and Glass Ionomer Sealants Applied as a Part of School-Based Caries Prevention Program.

BACKGROUND:Using of sealant on pits and fissures is likely one of the most generally well-known strategies by the new cavity-prevention systems.AIM:The purpose of this research is to measure the retentiveness of sealants of resin-modified ionomer glass cement (GIC) and resin pits and fissures, on the first permanent molars of special patients as a part of caries prevention program in schools.METHODS:The sample was comprised by 60 molars. Resin-based sealants on one side and glass-ionomer sealant on the contralateral side of the mouth. The molars were examined in three and six months after application for retention with three standards: TR: Totally Retained; PR: Partially Retained; and CL: Completely Lost.RESULTS:by the end of the study 60% of resin sealant was present. While 55% of GIC were retentive after 6 months.CONCLUSION:Resin sealants are more retentive than glass ionomer sealants in school-based carries prevention program.

Direct Writing of Microfluidic Three-Dimensional Photonic Crystal Structures for Terahertz Technology Applications.

The direct writing technology was used to create microfluidic three-dimensional terahertz photonic crystal structures (3D-TPCSs) with a glass cement ink, which demonstrated potentials for various terahertz technology applications. By a simple injection of liquid alloy into them, metallic 3D-TPCSs could be created easily at a low cost to solve the challenges of their creation by current approaches. These microfluidic 3D-TPCSs also possessed a specific capability of changing their terahertz properties in real time without structural changes by injecting fluidic media with different dielectric properties into their microfluidic channels, which endowed them the easy integration into various terahertz devices that require terahertz modulation for a wide range of applications. Due to their microsized channel structure and subsequent reduction of terahertz irradiation absorption by water in them, they demonstrated the potential as real time, nondestructive biological and chemical sensors to detect changes occurring in them in the fluidic media with the terahertz time-domain spectroscopy (THz-TDS).

Evaluation of Strontium-Doped Nanobioactive Glass Cement for Dentin-Pulp Complex Regeneration Therapy.

Introducing new generations of injectable bioactive types of cement that fulfill excellent injectability, rapid self-setting, high bioactivity, proper biodegradability, and fast therapeutic ion-releasing capability is highly demanded for tooth and bone regeneration. Here, we announce therapeutic fast ion-releasing nanobiocements (NBCs) based on sol-gel-processed calcium silicate mesoporous nanobioactive glass with or without strontium (NBC, Sr-free and Sr-NBC, Sr-doped). The stimulating role of Sr ions in odontogenesis of stem cells derived from dental pulp (DPSCs) and in in vivo dentin formation has been investigated. The nanobiocement was formulated through the mixing of bioactive glass nanopowder with a phosphate-buffered saline (P/L = 0.5 g/mL) to form a soft cement paste that hardens within 5-10 min in the ambient environment. The self-setting originated from a setting reaction involving the deposition of hydroxyapatite as evidenced from X-ray diffraction. Both nanobiocements showed the rapid release of therapeutic ions with biologically effective doses, including strontium (Sr), calcium (Ca), or silicon (Si). In vitro cell cultures with DPSCs showed excellent biocompatibility and high odontogenic potential, especially from Sr-NBC. In an in vivo study, Sr-NBC showed more new dentin formation compared to that of NBC, revealed by two different animal models (odontogenesis in subcutaneous and natural tooth environment). Also, NBCs showed high loading capacities of simvastatin used as a model drug. Taken together, Sr-NBC could be considered as a multifunctional nanobiocement with high bioactivity, excellent biodegradability, fast therapeutic ion release, and high drug loading capability, which potentiates its application in dentin-pulp complex regeneration therapy.

Strontium Modulates Osteogenic Activity of Bone Cement Composed of Bioactive Borosilicate Glass Particles by Activating Wnt/Β-Catenin and Bmp Signalling Pathway

Sr (Strontium) facilitates bone regeneration by stimulating osteoblastic activity and inhibiting osteoclastic resorption simultaneously. Our previous study showed that incorporation of Sr into bioactive borate glass cement enhanced the osteogenic capacity in vivo. However, the amount of Sr in the cement to provide an optimal combination of physicochemical properties and capacity to stimulate bone regeneration and the underlying molecular mechanism of this stimulation is yet to be determined. In this study, bone cements composed of bioactive borosilicate glass particles substituted with varying amounts of Sr (0mol% to 12mol% SrO) were created and evaluated in vitro and in vivo. The setting time of the cement increased with Sr substitution of the glass. Upon immersion in PBS, the cement degraded and converted more slowly to HA (hydroxyapatite) with increasing Sr substitution. The released Sr2+ modulated the proliferation, differentiation, and mineralization of hBMSCs in vitro. Osteogenic characteristics was optimal enhanced with cement (designated BG6Sr) composed of particles substituted with 6mol% SrO. When implanted in rabbit femoral condyle defects, BG6Sr cement supported better peri-implant bone formation and bone-implant contact, comparing to cements substituted with 0mol% or 9mol% SrO. The underlying mechanisms are involved in the activation of both Wnt/β-catenin and BMP signal pathway in osteogenic differentiation of hBMSCs. These results indicate that BG6Sr cement has a promising combination of physicochemical properties and biological performance for minimally invasive healing of bone defects.

Predicting CBR Values of Black Cotton Soil Stabilized with Cement and Waste Glass Admixture Using Regression Model

In highway constructions, sub-grade and sub-base soil stabilization has been used as one of the prime and major process for many years in order to improve the engineering properties of soil. The strength of theses layers is indicated by their California bearing ratio (CBR) value which is quite expensive and time consuming. In order to overcome this situation, this study presents a methodology for predicting soaked California Bearing Ration (CBR) value of Black Cotton Soil Stabilized with Cement and Waste Glass Admixture using Multiple Regression Analysis (MRA). Experimental test results such Atterberg limit (Liquid limit (LL), Plastic limit (PL) and Plasticity index (PI)), Compaction characteristics of two compactive efforts namely standard proctor (SP) and modified proctor (MP) (maximum dry density (MDD) and optimum moisture content (OMC)), CBR, Waste glass (WG) content and Cement content (Cm), obtained from a laboratory at Abubakar Tafawa Balewa University Bauchi, Nigeria, have been employed in developing multiple regression models. California Bearing Ration was taken as the dependent variables while Liquid limit, Plastic limit, maximum dry density, optimum moisture content, waste glass content and Cement content were taken as independent variables. The regression analysis calculated the error mean square (MSE) for each possible model, and models with large MSE were not selected for the best regression equations. The best models have a minimum value of MSE occurring for the six-variable model (Cm, WG, LL, PL, OMCsp, MDDsp) and (Cm, WG, PL, LL, OMCmp, MDDmp) with a corresponding higher value of coefficient of multiple determination R2 = 0.98 and 0.94. The performance evaluation of the fitted regression models indicates a strong correlation (R2 = 0.89 - 0.98) between the mentioned variables, and the model equations developed from this work provided a very good prediction of the response, as the equations can be employed for making estimates of soaked CBR of other black cotton soils having similar geotechnical properties.

Influence of the addition of glass powder and marble powder on the physical and mechanical behavior of composite cement

The development of new building materials is the problem of time, where researchers trying to find inexpensive equipment adapted in line with the field of use, the use of additional materials in the cement industry continues to increase and is often called on these metal additions materials we get from natural sources or remnants of industrial materials. In addition, the use leads to a reduction of clinker consumption and contribute to solving environmental problems in a simple and economical manner. The main objective of this experimental work is to study the proportion of powdered glass and marble dust on the physical and mechanical behavior of the composite cement and mortar. The obtained results the results obtained show that the partial compensation of glass cement powder 10% give the best values.

Pore Characterization of Volcanic Tuffs Used as Building Stone in Afyonkarahisar (Turkey)

The tuffs have been used as a building material for hundreds of years. The physical and mechanical properties of tuffs are affected by the amount of pore and its geometry. The pore characteristics of the building natural stone of Seydiler and Ayazini (Afyonkarahisar-Turkey) tuffs were investigated in this article. For determination of the mineralogical and petrographical properties of the tuff; a polarizing optical microscope, X-ray diffractometry and scanning electron microscope (SEM) were used. Tuffs are composed of a mineral assemblage of various crystals including quartz, feldspar; mafic mineral is biotite and rock particles with glass cement. SEM images show the presence of numerous voids in tuffs. The mean value of effective porosity of the Ayazini and Seydiler tuffs was 37.3% and 36.0%. Mercury porosimetry was used to determine the pore size distribution. Ayazini tuffs have pore sizes ranging from about 200.000 to 10 nm and Seydiler tuffs ranging from about 7.000 to 10 nm.

Research and application progress of bioactive glass in bone repair

To review the research and application progress of bioactive glass in bone repair. The recently published literature concerning bioactive glass in bone repair was reviewed and summarized. Bioactive glass can classified different types, such as bioactive glass particulate, bioactive glass scaffold, bioactive glass coating, injectable bioactive glass cement, and bioactive glass delivery system. Bioactive glass has been well studied in the field of bone repair due to its excellent biological properties. Also, the remarkable progress has been made in various aspects. Bioactive glass is a reliable material of bone repair and will play an even more important role in the future.

Influence of the Number of Bleaching Sessions on Fracture Resistance and Dentin Microhardness of Endodontically Treated Teeth

ABSTRACT Objectives To evaluate the effects of number of bleaching sessions on fracture resistance and dentin microhardness in endodontically treated teeth using 15% hydrogen peroxide with titanium dioxide nanoparticles (15HPTiO2) associated to light emitting diode (LED)—laser system. Materials and methods Forty human incisors were endodontically treated and divided according to the number of bleaching sessions (n = 10, each group): G1 — no treatment G2 — one; G3 — two; and G4 — three sessions. The 15HPTiO2 was applied within the pulp chamber and on the buccal surface, then photoactivated using LED—laser. All experimental specimens were restored with ionomer glass cement between each session and in the final treatment. Specimens were then subjected to the fracture resistance test (kN), using an electromechanical machine. To the dentin microhardness evaluation, 40 crown extracted endodontically treated human teeth were longitudinally sectioned, divided into groups as previously described (n = 10), and submitted to similar bleaching protocol. Dentin microhardness was evaluated before and after the final dental bleaching session in each group using Knoop indentator. Data were analyzed by analysis of variance (ANOVA) and Tukey tests (p = 0.05). Results The fracture resistance values were similar among all groups (p > 0.05). The number of dental bleaching sessions had a negative influence on the microhardness dentin, because G4 > G3 > G2 > G1 (p < 0.05). Conclusion The number of bleaching sessions using 15% hydrogen peroxide with titanium dioxide nanoparticles associated to LED—laser system had no influence on the fracture resistance of the endodontically treated teeth crowns, but promoted a reduction in dentin microhardness. How to cite this article Garrido LDMA, Kuga MC, Kalatzis- Sousa NG, Dantas AAR, Tonetto MR, Leonardo RDT, Jordão- Basso KCF, Lima SL, Borges AH, Bandeca MC. Influence of the Number of Bleaching Sessions on Fracture Resistance and Dentin Microhardness of Endodontically Treated Teeth. World J Dent 2017;8(1):5-9.

Evaluation of an injectable bioactive borate glass cement to heal bone defects in a rabbit femoral condyle model

There is a need for synthetic biomaterials to heal bone defects using minimal invasive surgery. In the present study, an injectable cement composed of bioactive borate glass particles and a chitosan bonding solution was developed and evaluated for its capacity to heal bone defects in a rabbit femoral condyle model. The injectability and setting time of the cement in vitro decreased but the compressive strength increased (8±2MPa to 31±2MPa) as the ratio of glass particles to chitosan solution increased (from 1.0gml−1 to 2.5gml−1). Upon immersing the cement in phosphate-buffered saline, the glass particles reacted and converted to hydroxyapatite, imparting bioactivity to the cement. Osteoblastic MC3T3-E1 cells showed enhanced proliferation and alkaline phosphatase activity when incubated in media containing the soluble ionic product of the cement. The bioactive glass cement showed a better capacity to stimulate bone formation in rabbit femoral condyle defects at 12weeks postimplantation when compared to a commercial calcium sulfate cement. The injectable bioactive borate glass cement developed in this study could provide a promising biomaterial to heal bone defects by minimal invasive surgery.

Development of novel strontium containing bioactive glass based calcium phosphate cement

ObjectiveThe aim of this study was to investigate the effect on properties of increasing strontium substitution for calcium in bioactive glasses used as precursors for novel calcium phosphate cements. MethodsGlasses were produced by progressively substituting strontium for calcium. Cements were prepared by mixing the glass powder with Ca(H2PO4)2 powder with a 2.5% solution of Na2HPO4. Setting times and compressive strength were measured after 1h, 1 day, 7 days and 28 days immersion in Tris buffer solution. X-ray diffraction (XRD), Fourier transform infrared spectroscopy and radiopacity were measured and crystal morphology was assessed using scanning electron microscopy. ResultsA correlation between the phases formed, morphology of the crystallites, setting time and compressive strength were analyzed. Setting time increased proportionally with strontium substitution in the glass up to 25%, whereas for higher substitutions it decreased. Compressive strength showed a maximum value of 12.5MPa and was strongly influenced by the interlocking of the crystals and their morphology. XRD showed that the presence of strontium influenced the crystal phases formed. Octacalcium phosphate (Ca8H2(PO4)6·5H2O, OCP) was the main phase present after 1h and 1 day whereas after 28 days OCP was completely transformed to strontium-containing hydroxyapatite (SrxCa(10−x)(PO4)6(OH)2, SrHA). Radiopacity increased proportionally to strontium substitution in the glass. SignificanceA novel method to develop a bone substitute forming in vitro SrHA as a final product by using a bioactive glass as a precursor was shown. These novel injectable bioactive glass cements are promising materials for dental and orthopedic applications. Further in vivo characterizations are being conducted.

Three-dimensional printing of tricalcium silicate/mesoporous bioactive glass cement scaffolds for bone regeneration.

Bone defects, particularly large bone defects resulting from infections, trauma, surgical resection or genetic malformations, remain a significant challenge for clinicians. In this study, the tricalcium silicate/mesoporous bioactive glass (C3S/MBG) cement scaffolds were successfully fabricated for the first time by 3D printing with a curing process, which combined the hydraulicity of C3S with the excellent biological property of MBG together. The C3S/MBG scaffolds exhibited 3D interconnected macropores (∼400 μm), high porosity (∼70%), enhanced mechanical strength (>12 MPa) and excellent apatite mineralization ability. Human bone marrow-derived mesenchymal stem cells (hBMSCs) were cultured on the scaffolds to evaluate their cell responses, and the results showed that C3S/MBG scaffolds could stimulate the attachment, proliferation and differentiation of hBMSCs with increasing MBG component. The critical-sized rat calvarial defect animal model was employed; further in vivo results indicated that both C3S and C3S/MBG30 scaffolds could induce new bone formation, but the C3S/MBG30 scaffolds significantly improved the osteogenic capacity compared to the pure C3S scaffolds. Therefore, the C3S/MBG cement scaffolds fabricated by 3D printing with a curing process would be a promising candidate for bone regeneration.

Case Study on Determination of Tensile Properties of Construction Sealants at Variable Temperatures

The authors of presented research case focused on possibilities of sealing porous as well as non – porous materials and analysed the measured results. It is the second article of the above mentioned authors dealing with sealed joints, however, in this case study the focus was placed on a group of industrially manufactured modified silyl polymer and polyurethane sealants. The research is based on the modified test procedure for the determination of adhesion and cohesion properties during maintained extension at variable temperatures, i.e. a high temperature of (70 + 2) °C and a temperature simulating freezing, i.e. (-20 + 2) °C, according to the European standard EN ISO 9047. The degree of specimen extension was set to amplitude of 20.0 % and the aim of the research case was to discover any differences that might appear in the resistance. The measured results demonstrate that there are significant differences between individual sealants in the results they provide in combination with specific material, e.g. wood appears to be a problematic substrate as well as glass cement or aluminium.

Simulations reveal the role of composition into the atomic-level flexibility of bioactive glass cements.

Bioactive glass ionomer cements (GICs), the reaction product of a fluoro-alumino-silicate glass and polyacrylic acid, have been in effective use in dentistry for over 40 years and more recently in orthopaedics and medical implantation. Their desirable properties have affirmed GIC's place in the medical materials community, yet are limited to non-load bearing applications due to the brittle nature of the hardened composite cement, thought to arise from the glass component and the interfaces it forms. Towards helping resolve the fundamental bases of the mechanical shortcomings of GICs, we report the 1st ever computational models of a GIC-relevant component. Ab initio molecular dynamics simulations were employed to generate and characterise three fluoro-alumino-silicate glasses of differing compositions with focus on resolving the atomic scale structural and dynamic contributions of aluminium, phosphorous and fluorine. Analyses of the glasses revealed rising F-content leading to the expansion of the glass network, compression of Al-F bonding, angular constraint at Al-pivots, localisation of alumino-phosphates and increased fluorine diffusion. Together, these changes to the structure, speciation and dynamics with raised fluorine content impart an overall rigidifying effect on the glass network, and suggest a predisposition to atomic-level inflexibility, which could manifest in the ionomer cements they form.

An injectable borate bioactive glass cement for bone repair: Preparation, bioactivity and setting mechanism

There is a need for synthetic biomaterials to reconstruct bone defects using minimal invasive surgery. In this study, the preparation, bioactivity and setting mechanism of an injectable cement composed of borate bioactive glass particles and a chitosan solution was evaluated as a function of varying solid to liquid (SL) ratio. As the SL ratio increased from 1.0g/ml to 2.5g/ml, the injectability and initial setting time decreased from 97±1% to 84±10% and from 16.9±0.9min to 3.0±0.5min, respectively, while the compressive strength of the cement increased from 8±2MPa to 31±2MPa. The cement maintained its cohesiveness in a vigorously stirred aqueous medium. When immersed in phosphate-buffered saline, the glass phase reacted and converted to hydroxyapatite. The setting mechanism of the cement appeared to involve a combination of processes, such as the sol–gel transition of the chitosan solution, formation of an interlocked interface between the converted glass surface and the chitosan, and bonding between the converted glass surface and the functional groups of the chitosan. By controlling the reaction between the glass particles and the chitosan solution, injectable cements can be created with the requisite workability, degradation, strength and bioactivity for bone repair applications.

Evaluation of injectable strontium-containing borate bioactive glass cement with enhanced osteogenic capacity in a critical-sized rabbit femoral condyle defect model.

The development of a new generation of injectable bone cements that are bioactive and have enhanced osteogenic capacity for rapid osseointegration is receiving considerable interest. In this study, a novel injectable cement (designated Sr-BBG) composed of strontium-doped borate bioactive glass particles and a chitosan-based bonding phase was prepared and evaluated in vitro and in vivo. The bioactive glass provided the benefits of bioactivity, conversion to hydroxyapatite, and the ability to stimulate osteogenesis, while the chitosan provided a cohesive biocompatible and biodegradable bonding phase. The Sr-BBG cement showed the ability to set in situ (initial setting time = 11.6 ± 1.2 min) and a compressive strength of 19 ± 1 MPa. The Sr-BBG cement enhanced the proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells in vitro when compared to a similar cement (BBG) composed of chitosan-bonded borate bioactive glass particles without Sr. Microcomputed tomography and histology of critical-sized rabbit femoral condyle defects implanted with the cements showed the osteogenic capacity of the Sr-BBG cement. New bone was observed at different distances from the Sr-BBG implants within eight weeks. The bone-implant contact index was significantly higher for the Sr-BBG implant than it was for the BBG implant. Together, the results indicate that this Sr-BBG cement is a promising implant for healing irregularly shaped bone defects using minimally invasive surgery.

Simulation of Thermal Behavior in Hollow-glass-microsphere-filled Cement Composites

In this paper, thermal behavior in cement composites filled with hollow glass microspheres was modeled by finite element method based on heat conduction theory. According to experimental observation of the microsphere distribution in the cement matrix material by the scanning electron microscope, a twodimensional unite cell including single hollow glass microsphere and cement material phase is chosen as the computational model, in which the specified temperature conditions are applied on the opposite edges of the cell to model heat transfer in the cell by finite element simulation. The effects of volume content and wall thickness of the microsphere, thermal conductivities of the wall and the cement on the effective thermal conductivity of the composite are investigated. Numerical results demonstrate that the developing lightweight cement-based composite can have significant lower thermal conductivity than the cement matrix itself by introducing the hollow glass microsphere.

Test of Adhesion and Cohesion of Silicone Sealants on Facade Cladding Materials within Extreme Weather Conditions

This research was carried out as part of project MPO FR - TI4/332 – New Technologies of Bonded Facade Cladding with Anchor Elements with Increased Resistance to Corrosion.This contribution concerns tests carried out to investigate the tensile properties of silicone sealants for use with facade cladding materials. The experimental part of the research is aimed at ascertaining the technical properties of sealants via the cyclic alternation of extension and compression of test specimens in test moulds. For the tests, industrially manufactured neutral and universal silicones were chosen from three different manufacturers. The aim of the research was to discover any differences that might appear in their resistance against alternating maintained extension and compression of the specimens under extreme temperature conditions, i.e. a high temperature of (70+2) °C and a temperature simulating freezing, i.e. (-20+2) °C. The cladding material used was fibre-cement composite boards (known as Cembonit), ceramic and glass cement facade claddings.The result of the measurements taken is a summary in which effective and unsuitable combinations of sealants and test substrates are outlined. The main conclusion is the fact that it is not possible to responsibly choose a suitable material without taking appropriate measurements or having previous experience. A secondary conclusion to this article is the fact that there are significant differences between individual sealants in the results they provide in combination with specific cladding material.