Glass Filler Research Articles

Representative volume element based micromechanical modelling of rod shaped glass filled epoxy composites

In this study, Representative Volume Element based micromechanical modeling technique has been implemented to assess the mechanical properties of glass filled epoxy composites. Rod shaped glass fillers having an aspect ratio of 80 were used for preparing the epoxy composite. The three-dimensional unit cell model of representative volume element was prepared with finite element analysis tool ANSYS 19 using the periodic square and hexagonal array with an assumption that there is a perfect bonding between the filler and the epoxy matrix. Results revealed that the tensile modulus increases and Poisson’s ratio decreases with increase in the volume fraction of the filler. To study the effect of filler volume fraction, the pulse echo techniques were used to experimentally measure the tensile modulus and Poisson’s ratio for 5% to 15% volume fraction of the filler. A good agreement was found between the RVE based predicted values and the experimental results.

Analysis of marginal integrity in dentistry composite fillings with flow layer under compression test.

Currently, composite materials dominate among the restorative materials used for direct aesthetic filling. Reinforcement of composites with glass fibers allows for the transfer of greater loads and better durability between the tooth tissue and the filling polymer. New approach to bonding liquid materials with composite with glass fillers is to introduce an additional protective barrier to load a higher force that is, compression test. So, the aim of the study was to analyze the structure of composite fillings, their integrity with tooth tissues and evaluation on the influence of the liquid composite layer on the strength of strength in the compression test. Moreover, the influence of thermal shocks on the bonding with the tooth tissues in the compression test was investigated. According to the results obtained in current research, using the flow composite as a combination with the fiber composite leads to a significant increase in mechanical properties, particularly in the compression test. HIGHLIGHTS: If flow-type composite fluid material are, the greater is strength of composite fillings. Glass fibers composite increase the mechanical strength.

Behaviour of different bioactive glasses incorporated in polydimethylsiloxane endodontic sealer

ObjectivesThe aim of this study was to analyze the behavior of different bioactive glass fillers (BAGs) embedded in a polydimethylsiloxane matrix of an endodontic sealer. MethodsThree different endodontic sealers were fabricated using S53P4, 45S5 and 18−06 glass fillers. Endodontic sealer Guttaflow Bioseal consisting of polydimethylsiloxane (PDMS) matrix was used as base of the experimental sealers. Behaviors of different glass fillers leaching from polymer matrix was studied in vitro for 14 days by measuring static ion dissolution profiles of Si, Na, Ca and P -ions. In addition, pH of the simulated bodyfluid (SBF) was monitored during the 14 days and all the sealer samples was examined with SEM/EDX analysis on the surface. Identical but non-glass filler containing polydimethylsiloxane-based sealer was used as a control material. ResultsBy the time point of 24 h sealer with 45S5 had released twice as much of Si-ions compared to sealer with S53P4. No statistical differences of Na, Ca and P -ions dissolution were observed in the first 168 h for any groups whereas concentrations of Ca and P -ions decreased with 45S5 significantly after 336 h. Highest pH was measured for sealers with glass filler 45S5 and S53P4 (7.64–7.65). Visible mineral precipitation was observed only on sealer surfaces after 336 h’ time period with groups of 45S5 and S53P4. However, presence of calcium and phosphorus oxides was confirmed only with 45S5. SignificanceBioactive glass type 45S5 outperforms S53P4 and 18−06 by acting more dynamically in vitro set-up

An in vitro study to evaluate and compare the remineralizing potential among Casein Phosphopeptide-amorphous Calcium Phosphate (CPP-ACP) with fluoride and surface pre-reacted glass (S-PRG) fillers using quantitative analysis

Background- Early treatment of white spot lesions is essential to prevent the progression of the lesion. Aim - To evaluate and compare the remineralizing potential of CPP-ACP with fluoride (Casein Phospho Peptide-Amorphous Calcium Phosphate) and S-PRG fillers (Surface Pre reacted glass fillers) using atomic absorption spectroscopy and colorimetric method. Materials and methods- Forty sound human premolars were used in this study. They were divided into two groups (A & B), consisting of 20 samples in each. White spot lesions (WSLs) were established on the window (4x4 mm2) created on the buccal surfaces of the samples. Samples in group A were treated with casein phosphopeptide amorphous calcium phosphate (CPP-ACP) with fluoride, those of group B were treated with S-PRG Fillers. The sample teeth were immersed in a demineralizing solution for 4 days. All the samples were subjected to loss of mineral content (wt %), i.e., calcium, using atomic absorption spectroscopy and phosphorus using the colorimetric method. Results- Statistical analysis was performed using one?way analysis of variance, Tukey’s and paired t?tests. Group A exhibited the highest remineralizing potential, followed by Group B. Statistically, a significant difference (p=0.001) was observed between the two groups. Conclusion- There was a significant difference in remineralizing potential of CPP-ACP with fluoride and S-PRG Fillers. CPP-ACP with fluoride appears to be an effective technique in the remineralization of white spot lesions.

Effect of Heat and Moisture Exposure on the Strength Properties of Polymer Composite Materials

Slabs of polymer composite materials (PCMs) based on glass, carbon, and organic fillers and various binders were made according to one technological molding mode. The main methods for determination of the effects of thermal and moisture factors on the PCM properties were selected. The effect of thermal and moisture factors on the physical and mechanical properties of PCMs was studied. The studies have shown the positive effect of additional heat treatment of PCM on its properties. The microhardness of the matrix in the samples was investigated before and after heat treatment.

Evaluation of rheological behaviour of flowable dental composites reinforced with low aspect ratio micro-sized glass fibres

ObjectiveExperimental investigation is carried out to determine the flowability and stickiness of the developed composite material for dental restoration containing low aspect ratio (AR ≤ 100) surface treated micro-sized glass fibres. MethodsSpecimens are manufactured by mixing low AR (50/70/100) micro-sized glass fibres with two different weight fractions (5%/10%) into UDMA/TEGDMA based resin. Particulate filler composite (PFC) containing 55% glass fillers is used as the control group. Dynamic oscillatory strain sweep tests are conducted to analyse the linear viscoelastic behaviour. Solid-to fluidic transition behaviour of dental composites is also calculated in terms of flow and yield stresses. Furthermore, the oscillatory frequency sweep tests are conducted at three different strains (0.5%, 5% and 50%) resembling the positioning of unset paste onto restorations for different real-life clinical situations. Additionally, stickiness of dental composites with handling instrument (steel) and dentine covered with bonding agent is also evaluated. ResultsThe results suggested the all the FRC groups exhibited non-Newtonian, shear-thinning behaviour. It is further established that inclusion of 5% of 50/70AR fibres into dental composites does not affect the flowability. Simultaneously, stickiness with dentine covered with bonding agent is more for these two compositions as compared to that of handling instrument (steel). SignificanceThis study suggest that visco-elastic properties of dental composites are greatly affected by the type of filler (spherical shaped particulate fillers or rod-shaped fibres) as well as fibre weight fraction/fibre AR. This phenomenon can be attributed to the varying interactions between micro-sized fibres of different AR/weight fraction, particulate fillers and monomers.

Joining of Hypereutectic Al-50Si Alloys Using Lead-Free Brazing Filler Glass in Air.

Hypereutectic Al-Si alloys are attractive materials in the fields of electronic packaging and aerospace. A Bi2O3-ZnO-B2O3 system lead-free brazing filler glass was employed to braze hypereutectic Al-50Si alloys in air. The hypereutectic Al-50Si alloys were pre-oxidized and the low-temperature glass powder was flake-shaped in the brazing process. The effects of brazing temperature and time on joints microstructure evolution, resulting mechanical strength, and air tightness were systematically investigated. The results indicated that the maximum shear strength of the joint was 34.49 MPa and leakage rate was 1.0 × 10−10 Pa m3/s at a temperature of 495 °C for 30 min. Crystalline phases, including Bi24B2O39 and Bi2O3, were generated in the glass joint. The formation of a diffusion transition layer with a thickness of 3 μm, including elements of Al, Si, Zn, Bi, Na, and B, was the key to form an effective joint. The elements of Al, Si, and Bi had a short diffusion distance while the elements of Zn, Na, and B diffused in a long way under brazing condition.

Microstructure evolution and mechanical properties of YAG/YAG joint using bismuth-borate glass

Joining of Y3Al5O12 garnet single crystal (YAG) was achieved by using a bismuth-borate based glass filler. The thermal properties of glass filler were experimentally determined and the wettability of molten glass on YAG was investigated. The YAG reacted with glass to form ZnAl2O4 particles and Y2O3 nanowires successively as joining temperature is above 625℃. ZnAl2O4 preferentially nucleated and grew on Y2O3 nanowires. The cooperative growth of the two phases accelerated YAG decomposition, which in turn led to cluster growth of Y2O3 nanowires and aggregation of ZnAl2O4 particles at elevated temperature. The microstructure evolution and reaction mechanism were studied. The highest shear strength of 29.6 ± 5.2 MPa was obtained for the joint brazed at 650℃. The fracture morphology demonstrated that the dispersive strengthening of ZnAl2O4 and stress relief by Y2O3 nanowire network contributed to the superior mechanical performance.

Evaluation of the Effect of Glass Granule Size on Water Damage Performance of Asphalt Mixtures

Economic growth and the increase in the population trigger consumption and increase the amount of waste produced. One of the resulting wastes is glass and using of these large amount of glass waste materials by environmental methods is seen as an important issue. On the other hand, there are difficulties due to the decrease of natural resources in the supply of aggregates used in asphalt pavements. In this study, the use of waste glass instead of natural aggregates in asphalt pavements was investigated in terms of water damage. In addition to base bitumen, hydrated lime modified and SBS modified bitumen were used in experimental studies. The waste glass was added in two different sizes (as filler materials and 2 mm sized fine aggregate) and three addition ratios (20%, 30% and 40%) instead of basalt aggregates. The asphalt mix samples produced in optimum bitumen contents were evaluated for water damage by AASHTO T 283 method. Asphalt mixture with 20% glass filler showed the highest water damage resistance. Among the options where the glass aggregate size was chosen as 2 mm, the highest water damage resistance was realized at addition rate of 30%. Both hydrated lime and SBS polymer were effective in improving water damage resistance. However, the highest tensile strength ratio was obtained with hydrated lime. The optimum bitumen contents of the mixtures with glass aggregates produced with both base and modified bitumen were decreased compared to that produced entirely with basalt aggregate. According to the test results, it is understood that the filler materials produced from waste glasses can be used instead of natural aggregate filler.

Effects of systematically varied thiourethane-functionalized filler concentration on polymerization behavior and relevant clinical properties of dental composites

Introduction of thiourethane (TU) oligomer to resin-based dental restorative materials reduces stress and improves fracture toughness without compromising conversion. Localization of TU at the resin-filler interface via silanization procedures may lead to more substantial stress reduction and clinical property enhancements. The objective of this study was to evaluate composite properties as a function of TU-functionalized filler concentration. TU oligomers were synthesized using click-chemistry techniques and subsequently silanized to barium glass filler. Resin-based composites were formulated using varying ratios of TU-functionalized filler and conventional methacrylate-silanized barium filler. Material property testing included thermogravimetric analysis, real-time polymerization kinetics and depth of cure, polymerization stress, stress relaxation and fracture toughness. Clinical property testing included water sorption/solubility, composite paste viscosity, and gloss and surface roughness measured before and after subjecting the samples to 6 h of continuous tooth brushing in a custom-built apparatus using a toothpaste/water mixture. Increasing TU-filler in the composite resulted in as much as a 78% reduction in stress, coupled with an increase in fracture toughness. Conversion was similar for all groups. After simulated tooth brushing, gloss reduction was lower for TU-containing composites and surface roughness was less than or equal to the control.

Strength and Durability Test on Partial Replacement of Cement by Glass Powder in Self-Compacting Concrete

Self-compacting solid that can stream under its own weight and complete the shape work, even within the sight of thick support, without requiring any vibration while saving homogeneity. ). SCC can likewise be utilized in circumstances where mechanical compaction for new cement is troublesome or difficult to utilize, for example, submerged cementing, projecting in-situ heap establishments, machine bases and sections or dividers with clogged fortification The piece of SCC is like that of ordinary cement but to accomplish self-stream admixtures, for example, fly debris, glass filler, calcareous powder, The various properties of the materials in the exploratory program were resolved. Glass Powders qualities and the benefits of utilizing them with concrete were examined. An exhaustive investigation on glass powder concrete was likewise directed. Concrete will be supplanted by 5 percent, 10%, 15 percent, 20%, 25 percent, concrete weight. The solid shapes, chambers and crystals were projected 150x150x150 mm, 150 mm x 300mmhigh, 700x150x150 mm. Utilizing swamp cone test, super plasticizer will be included for improved usefulness and ideal measurements was determined. Distinctive quality and continuance tests will be performed.

Novel Crown Cement Containing Antibacterial Monomer and Calcium Phosphate Nanoparticles.

Oral biofilm accumulation at the tooth–restoration interface often leads to recurrent dental caries and restoration failure. The objectives of this study were to: (1) develop a novel bioactive crown cement containing dimethylaminohexadecyl methacrylate (DMAHDM) and nano-sized amorphous calcium phosphate (NACP), and (2) investigate the mechanical properties, anti-biofilm activity, and calcium (Ca2+) and phosphate (PO43−) ion release of the crown cement for the first time. The cement matrix consisted of pyromellitic glycerol dimethacrylate and ethoxylated bisphenol-A dimethacrylate monomers and was denoted PEHB resin matrix. The following cements were tested: (1) RelyX luting cement (commercial control); (2) 55% PEHB + 45% glass fillers (experimental control); (3) 55% PEHB + 20% glass + 25% NACP + 0% DMAHDM; (4) 52% PEHB + 20% glass + 25% NACP + 3% DMAHDM; (5) 51% PEHB + 20% glass + 25% NACP + 4% DMAHDM; (6) 50% PEHB + 20% glass + 25% NACP + 5% DMAHDM. Mechanical properties and ion release were measured. Streptococcus mutans (S. mutans) biofilms were grown on cements, and colony-forming units (CFUs) and other biofilm properties were measured. The novel bioactive cement demonstrated strong antibacterial properties and high levels of Ca2+ and PO43− ion release to remineralize tooth lesions. Adding NACP and DMAHDM into the cement did not adversely affect the mechanical properties and dentin bonding strength. In conclusion, the novel NACP + DMAHDM crown cement has excellent potential for restoration cementation to inhibit caries by suppressing oral biofilm growth and increasing remineralization via Ca2+ and PO43− ions. The NACP + DMAHDM composition may have wide applicability to other biomaterials to promote hard-tissue formation and combat bacterial infection.

Thiourethane filler functionalization for dental resin composites: Concentration-dependent effects on toughening, stress reduction and depth of cure

ObjectivesThe aim of this study was to modify the surface of fillers used in dental composites by the synthesis of two novel thiourethane oligomeric silanes, used to functionalize the silica-containing inorganic particles. Several thiourethane silane concentrations were tested during the silanization process to systematically assess the effect of silane coverage on experimental composite conversion, polymerization stress and fracture toughness. Materials and methodsTwo different thiourethane silanes were synthesized based either on 1,6-hexanediol-diissocynate (HDDI), or 1,3-bis(1-isocyanato-1-methylethyl) benzene (BDI). Conventional 3-(Trimethoxysilyl)propyl methacrylate was used as the control. Glass fillers were silanized with 1, 2 or 4 wt% of each thiourethane silane, then evaluated by thermogravimetrical analysis. Photopolymerizable resin composites were prepared with Bis-GMA/UDMA/TEGDMA and 50 wt% silanized glass filler. Polymerization kinetics and degree of conversion were tested using Near-IR. Bioman was used to test polymerization stress. Data were analyzed with two-way ANOVA/Tukey's test (α = 5%). ResultsThe mass of silane coupled to the filler increased with the concentrations of thiourethane in the silanizing solution, as expected. Thiourethane-containing groups exhibited significantly higher degree of conversion compared to control groups, except for BDI 4%. HDDI 4%, BDI 2% and BDI 4% showed significantly lower polymerization stress than control groups. HDDI 4% exhibited significantly higher fracture toughness. Conclusions and clinical significanceNovel filler functionalization with thiourethane silanes may be a promising alternative for improving dental composites properties by significantly increasing the degree of conversion, fracture toughness and reducing the polymerization stress.

Polymerization shrinkage behaviour of resin composites functionalized with unsilanized bioactive glass fillers

Previous work has shown that partial replacement of reinforcing fillers with unsilanized silica particles can diminish polymerization shrinkage stress of dental resin composites. The aim of the present study was to investigate whether such an effect can be attained by using unsilanized bioactive glass (BG). Incorporating BG fillers into resin composites is interesting due to their potential for exerting caries-preventive effects. Experimental light-curable composites with a total filler load of 77 wt% were prepared. Reinforcing fillers were partially replaced with 0–60 wt% of BG 45S5 and an experimental low-sodium fluoride-containing BG. The following properties were investigated: linear shrinkage, degree of conversion, shrinkage stress, maximum shrinkage stress rate, and time to achieve maximum shrinkage stress rate. The diminishing effect of BG 45S5 on shrinkage stress was mediated by a decrease in degree of conversion caused by this BG type. In contrast, as the degree of conversion remained unaffected by the experimental BG, the resulting shrinkage behaviour was governed by the effect of varying amounts of silanized and unsilanized fillers on material’s viscoelastic properties. The replacement of silanized reinforcing fillers with unsilanized BG did not reduce polymerization shrinkage stress unless the reduction was attained indirectly through a diminished degree of conversion.

PEEK-matrix composites containing different content of natural silica fibers or particulate lithium‑zirconium silicate glass fillers: Coefficient of friction and wear volume measurements

The purpose of this work was to evaluate the friction and sliding wear behavior of poly-ether-ether ketone (PEEK) matrix composites containing natural amorphous silica fibers (NASF) or particulate lithium‑zirconium silicate (LZSA) glass-ceramics. PEEK and PEEK containing different weight content (10, 20, and 30 wt%) of LZSA or NASF were processed by hot pressing. Reciprocating sliding wear tests were performed on the specimens in artificial saliva solution against an alumina ball on 30 N normal force. Tests were performed at 1 Hz sliding frequency, and at 4 mm stroke length in artificial saliva solution. The worn surfaces were morphologically inspected by field emission guns scanning electron microscopy (FEGSEM) to calculate the wear volume. Coefficient of friction values recorded on PEEK or PEEK-NASF composites against alumina were lower than those on PEEK-LZSA composites. The presence of LZSA particles negatively affected the wear resistance of the PEEK composites. On sliding tests mimicking oral conditions, PEEK composites containing NASF revealed low friction and high wear resistance close to that one exhibited by PEEK. Such results can stimulate further studies on the processing and tribological characterization of PEEK composites including different percentage of natural amorphous silica fibers.

A study of physical and mechanical characteristics of polymer composite materials by ultrasonic technique

This work is concerned with the determining of physical and mechanical characteristics (dynamic elastic modulus along the direction of reinforcement, porosity, density, percentage of binder, strength) of fiberglass plastics by ultrasonic technique. The techniques, which are currently used for evaluation of the above-mentioned parameters of polymeric composite materials, are presented. The ultrasonic technique of physical and mechanical characteristics determining of glass fiber reinforced plastics for radio engineering purpose on the base of quarzitic, glass and siliceous fillers is proposed.

An antibacterial dental light-cured glass-ionomer cement with improved hardness

An antibacterial dental light-cured glass-ionomer cement has been developed and evaluated. An antibacterial furanone derivative was synthesized and covalently attached onto the surface of alumina filler particles. The formed antibacterial fillers were then mixed into a light-curable glass-ionomer cement formulation. Surface hardness and bacterial viability were used to evaluate the modified cements. Effects of coated furanone moiety content on the modified fillers, modified alumina filler particle size and loading, and total glass filler content were investigated. Results showed that increasing antibacterial furanone content, modified particle size and loading, and total glass filler content generally increased surface hardness. Increasing furanone moiety, filler loading and total filler content increased antibacterial activity. On the other hand, increasing particle size decreased antibacterial activity. The leaching tests indicate that the modified experimental cement showed no leachable antibacterial component to bacteria and cells

Polymerization and shrinkage stress formation of experimental resin composites doped with nano- vs. micron-sized bioactive glasses.

This study investigated the effect of adding bioactive glass 45S5 (BG) of different particle sizes to dental composite on resin polymerization and shrinkage stress formation. Commercial flowable composite was mixed with either 15 wt% BG fillers (nanometric, micrometric, or hybrid BG) or inert barium glass. Real-time linear polymerization shrinkage and shrinkage stress were recorded, and the degree of conversion was measured using FTIR spectroscopy. The commercial (unmodified) composite developed significantly higher linear shrinkage and shrinkage stress than the groups with 15 wt% added inert or BG fillers. After adding inert barium glass, the composite showed significantly higher linear shrinkage than when micrometric BG was added. The addition of bioactive or inert glass fillers did not affect the degree of conversion. Shrinkage stress can be reduced by adding inert or bioactive fillers (nano- and/or microparticulate BG) without affecting monomer conversion.

Physical Properties of Glass Ionomer Cement Containing Pre-Reacted Spherical Glass Fillers.

The aim of this study was to assess the effect of different commercial liquid phases (Ketac, Riva, and Fuji IX) and the use of spherical pre-reacted glass (SPG) fillers on cement maturation, fluoride release, compressive (CS) and biaxial flexural strength (BFS) of experimental glass ionomer cements (GICs). The experimental GICs (Ketac_M, Riva_M, FujiIX_M) were prepared by mixing SPG fillers with commercial liquid phases using the powder to liquid mass ratio of 2.5:1. FTIR-ATR was used to assess the maturation of GICs. Diffusion coefficient of fluoride (DF) and cumulative fluoride release (CF) in deionized water was determined using the fluoride ion specific electrode (n=3). CS and BFS at 24 h were also tested (n=6). Commercial GICs were used as comparisons. Riva and Riva_M exhibited rapid polyacrylate salt formation. The highest DF and CF were observed with Riva_M (1.65x10-9 cm2/s) and Riva (77 ppm) respectively. Using SPG fillers enhanced DF of GICs on average from ~2.5x10-9 cm2/s to ~3.0x10-9 cm2/s but reduced CF of the materials on average from ~51 ppm to ~42 ppm. The CS and BFS of Ketac_M (144 and 22 MPa) and Fuji IX_M (123 and 30 MPa) were comparable to commercial materials. Using SPG with Riva significantly reduced CS and BFS from 123 MPa to 55 MPa and 42 MPa to 28 MPa respectively. The use of SPG fillers enhanced DF but reduced CF of GICs. Using SPG with Ketac or Fuji IX liquids provided comparable strength to the commercial materials.

The effect of powder to liquid ratio on physical properties and fluoride release of glass ionomer cements containing pre-reacted spherical glass fillers.

The aim was to assess the effect of powder to liquid ratio (PLR) on setting time, fluoride release, and compressive strength of conventional glass ionomer cements (GICs) containing pre-reacted spherical glass fillers (SPG). GICs were prepared by mixing SPG with Fuji IX Universal liquid using PLR of 1:1, 1.5:1, 2:1, 2.5:1, 3:1. Setting time decreased from 221 to 51 s upon rising PLR. Increasing PLR decreased cumulative fluoride release (33 to 13 ppm). Diffusion coefficient of fluoride of experimental GICs (1.6-1.8×10-8 cm2/s) was comparable with that of Fuji IX Universal (1.6×10-8 cm2/s). Compressive strength of PLR 2:1 to 3:1 (93-140 MPa) were comparable with that of Fuji IX Universal (124 MPa). These results demonstrated that rising powder ratio reduced setting time, fluoride release, and compressive strength of GICs. However, the setting time and strength experimental GICs with PLR greater than 2:1 were in the acceptable range of the ISO standard.