The effect of resin matrix composition on mechanical properties of e-glass fiber-reinforced composite for dental use

The effects of resin matrix composition including bis-phenol-A-diglycidyl dimethacrylate (bis-GMA)-methyl methacrylate (MMA) based or urethane dimethacrylate (UEDMA)-triethylene glycol dimethacrylate (TEGDMA) based composition and storage conditions on the mechanical properties of E-glass fiber-reinforced composites (FRCs) were studied. Three experimental groups ('Exper 1', 'Exper 2', 'Exper 3') with differing UEDMA to TEGDMA ratio in the matrix together with a control group ('Control') based on bis-GMA-MMA resin matrix were prepared by light-curing. The storage conditions for each group were dry storage at room temperature for 24 h and 30- and 60-day immersion in deionized (DI) water at 37°C, which further divided each group into three subgroups. For all the four composition groups, mechanical properties including hardness, flexural strength and modulus in both three-point and four-point bendings were tested (n = 6), together with water sorption and solubility study (n = 6) and fracture site scanning with a scanning electron microscope (SEM). The experimental specimens were relatively strong and stiff in three-point bending compared to previous research. The same specimens in three-point bending had a lower flexural modulus and fractured at higher flexural stress than in four-point bending. According to the SEM images after fracture, some resin matrix was still bound to the fiber surface, showing cohesive-interfacial fracture type and relatively stable matrix-fiber adhesion. According to comprehensive analysis, the control group showed superior mechanical performance in most of the tests.postprin

Enhanced resin-composite bonding to zirconia framework after pretreatment with selected silane monomers

Objective: To evaluate the effect of five experimental silane monomer primers in vitro on the shear bond strength of a phosphate ester resin-composite cement bonded to a silicatized zirconia framework. Methods: A total of 144 planar zirconia (Procera AllZircon) specimens were subjected to tribochemical silica treatment, randomly divided into 12 sub-groups (n = 12), and silanized with 1.0% (v/v) activated solutions of 3-acryloxypropyltrimethoxysilane, 3 glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, styrylethyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane, which had been prepared in 95% ethanol (pH 4.5). A ready-to-use 3- methacryloxypropyltrimethoxysilane (RelyX™ Ceramic Primer) was used as the control. One resincomposite cement (RelyX™ Unicem) stub was bonded to each silicatized and silanized zirconia specimen. Half of the specimen groups were dry-tested and half were thermo-cycled at 6000 cycles between 5 °C and 55 °C, with a constant dwelling time of 30 s. The shear bond strengths of the cement stubs bonded to zirconia were measured using a universal testing machine using a constant cross-head speed of 1 mm/min. The silane primer activation was evaluated using Fourier-transform infrared spectroscopy. Results: The highest shear bond strength was obtained for 3- acryloxypropyltrimethoxysilane in dry storage, 11.7 MPa (SD, 2.3 MPa) and after thermo-cycling 17.6 (4.1) MPa for glycidoxypropyltrimethoxysilane. The lowest shear bond strength values were obtained with control silane: in dry storage, 4.5 (1.3) MPa, after thermo-cycling 6.5 (2.6) MPa. Thermo-cycling increased the bond strengths significantly (ANOVA, p < 0.001) and differently for each type of silane (ANOVA, p < 0.001). Significance: Silanization with five experimental silane primers in vitro produced significantly greater shear bond strengths than the ready-to-use control silane. © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.postprin

Resin Bonding to Silicatized Zirconia with Two Isocyanatosilanes and a Cross-linking Silane. Part I: Experimental

In this study we have investigated the effects of the chain length of hydrolyzable groups in two isocyanato silane coupling agents, 3-isocyanatopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane, on the shear bond strength of resin attached to silicatized zirconia. In addition, the effects of varying the silane concentration (at 0.1 vol% and 1.0 vol%) with or without the addition of a cross-linking silane (0.05 vol% or 0.5 vol% bis-1,2-(triethoxysilyl)ethane) were assessed. It was concluded that the use of the experimental primer of 3-isocyanatopropyltrimethoxysilane at either 0.1 vol% or 1 vol% with cross-linking silane resulted in significantly higher shear bond strengths than the use of primer without the cross-linking silane. © 2010 The Author(s).published_or_final_versionSpringer Open Choice, 31 May 201

Insights on Ceramics as Dental Materials. Part I: Ceramic Material Types in Dentistry

Ceramics are widely used biomaterials in prosthetic dentistry due to their attractive clinical properties. They are aesthetically pleasing with their color, shade and luster, and they are chemically stable. The main constituents of dental ceramic are Si-based inorganic materials, such as feldspar, quartz, and silica. Traditional feldspar-based ceramics are also referred to as "Porcelain". The crucial difference between a regular ceramic and a dental ceramic is the proportion of feldspar, quartz, and silica contained in the ceramic. A dental ceramic is a multiphase system, i. e. it contains a dispersed crystalline phase surrounded by a continuous amorphous phase (a glassy phase). Modern dental ceramics contain a higher proportion of the crystalline phase that significantly improves the biomechanical properties of ceramics. Examples of these high crystalline ceramics include lithium disilicate and zirconia. © 2011 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201

Experimental novel silane system in adhesion promotion between dental resin and pretreated titanium. Part II: Effect of long-term water storage: Rapid communication

In this study we have assessed the effect of long-term water storage at 37°C on silane-aided adhesion promotion. Five experimental silane blends were evaluated as adhesion-promoters. First, five functional organosilane monomers (silicon esters), 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, tetrakis-(2-methacryloxyethoxy)silane and bis-[3-(triethoxysilyl)propyl]tetrasulfide, were diluted to 1% (v/v) in 95% ethanol and blended with a non-functional cross-linking silane, bis-1,2-(triethoxysilyl)ethane (1%). A commercially available pre-activated silane product was used as the control. After activation by hydrolysis, each primer blend was applied to silica-coated Ti coupons. Stubs of experimental bis-phenol-A-diglycidyldimethacrylate (bis-GMA)-based resin were bonded by photo-polymerization onto the pretreated Ti coupons. Half of the specimens were stored in deionized water for 6 months and half for 12 months. The primer containing 3-acryloxypropyltrimethoxysilane and bis-1,2-(triethoxysilyl)ethane produced significantly higher shear bond strengths than the control silane and other experimental silane primers after both periods of storage. © 2010 The Author(s).published_or_final_versionSpringer Open Choice, 01 Dec 201

Resin Bonding to Silicatized Zirconia with Two Isocyanatosilanes and a Cross-linking Silane. Part II: Mechanistic Approach

In this paper we discuss and interpret the results of shear bond strengths achieved after the use of two silane coupling agents with isocyanato functionality, viz. 3-isocyanatopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane. The silanes were used alone and also blended with a non-functional cross-linking silane on silicatized zirconia before light-curing of resin stubs on the surface, as described elsewhere in the first part of our study (see "Part I: Experimental"). A series of reaction mechanisms and conceptual diagrams are also presented. The reaction mechanisms illustrating the effect of adding a cross-linking silane into a silane blend, the silane hydrolysis and the behavior of two organofunctional groups (isocyanate and alkene) of silanes upon reaction with Rely X Unicem Aplicap resin-composite cement are discussed in detail. © 2010 The Author(s).published_or_final_versionSpringer Open Choice, 31 May 201

Shear bond strength between resin and zirconia with two different silane blends

OBJECTIVE: To study in vitro the effect of two cross-linking silanes, bis-1,2-(triethoxysilyl)ethane and bis[3-(trimethoxysilyl)propyl]amine, blended with an organofunctional silane coupling agent, (3-acryloxypropyl)trimethoxysilane, on the shear bond strength between resin-composite cement and silicatized zirconia after dry storage and thermocycling. MATERIALS AND METHODS: Six tested groups of 90 samples of yttria stabilized zirconia were used for sample preparation. The surfaces of the zirconia were silica-coated. 3M ESPE Sil silane was used as a control. Solutions of (3-acryloxypropyl)trimethoxysilane with cross-linking silanes bis-1,2-(triethoxysilyl)ethane and bis[3-(trimethoxysilyl)propyl]amine were applied onto the surface of silicatized zirconia. 3M ESPE RelyX resin-composite cement was bonded onto the silicatized and silanized zirconia surface and light-cured. Three groups were tested under dry condition and the other three groups were tested for thermocycling. The shear bond strength was measured using a materials testing instrument. Group mean shear bond strengths were analysed by ANOVA at a significant level of p < 0.05. The zirconia surface composition was analysed by X-ray Photoelectron Spectroscopy. RESULTS: The highest shear bond strength was 11.8 +/- 3.5 MPa for (3-acryloxypropyl)trimethoxysilane blended with bis-1,2-(triethoxysilyl)ethane (dry storage). There was a significant difference between mean shear bond strength values for (3-acryloxypropyl)trimethoxysilane blended with two cross-linking silanes, bis-1,2-(triethoxysilyl)ethane and bis[3-(trimethoxysilyl)propyl]amine, after thermocycling (p < 3.9 x 10(-8)). Various surface treatments of zirconia influenced the surface roughness (p < 4.6 x 10(-6)). The chemical composition analysis showed there was an increase in silicon and oxygen content after sandblasting. CONCLUSIONS: The results suggest that the combination of functional (3-acryloxypropyl)trimethoxysilane with cross-linking bis[3-(trimethoxysilyl)propyl]amine showed superior hydrolytic stability than with bis-1,2-(triethoxysilyl)ethane.postprin

Experimental novel silane system in adhesion promotion between dental resin and pretreated titanium

Five silane blends were evaluated as experimental adhesion-promoter primers. First, five organosilane monomers (silicon esters), 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, tetrakis-(2-ethyloxyethoxy)silane and bis-[3-(triethoxysilyl)propyl]tetrasulfide, were diluted to 1% (v/v) and blended with a non-functional cross-linking silane, 1,2-bis-(triethoxysilyl)ethane (1%), in 95% ethanol. After activation, each blend was applied to silica-coated Ti coupons. A resin based on bis-phenol-A-diglycidyldimethacrylate was then bonded and photo-polymerized as stubs to the pretreated Ti coupons. Half of the specimens were stored in dry conditions and half were artificially aged by thermo-cycling. The primers containing 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane produced significantly higher shear bond strength values than the control silane, a standard pre-activated product used in clinical dentistry. © Springer Science+Business Media B.V. 2010.published_or_final_versionSpringer Open Choice, 01 Dec 201

Effects of different silane coupling agent monomers on flexural strength of an experimental filled resin composite

The hydrolytic stability of various silane combinations and their effects on biomechanical properties and water sorption of an experimental dental composite made of bis-GMA and TEGDMA and silane-treated fillers were evaluated. Four silane coupling agents and their blends with a cross-linker silane were used as coupling agents for the 0.7-μm BaSiO 3 fillers. The silanization was carried out in toluene containing 1% (v/v) of one of the four following organofunctional silane coupling agents: 3- acryloxypropyltrimethoxysilane, 3methacryloxypropyltrimethoxysilane, 3-styrylethyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane. Blends of these functional silanes with 1% (v/v) of a cross-linker silane, 1,2- bis -(triethoxysilyl)ethane were also used for silanization. Composites were prepared by mixing 5.00 g Ba-glass filler with 2.00 g of a resin mixture consisting of bis-GMA (58.8 wt%) and TEGDMA (39.2 wt%) in a high-speed mixer. Threepoint bending test specimens (2.0 mm × 2.0 mm × 25.0 mm) were fabricated (n= 8) in a mould and photo-polymerized. The degree of conversion was measured with FT-IR. Biomechanical testing was carried out according to the ISO 10477 standard. Specimens were tested (flexural strength) after 30 days of water storage (37° C, distilled water). Water sorption and solubility (in wt%) were also measured on 1, 2, 3, 5, 7, 14, 21 and 30 days in water storage. Statistical analysis with ANOVA showed that the highest flexural strength was obtained when 3-acryloxypropyltrimethoxysilane + 1,2- bis -(triethoxysilyl) ethane (100.5 MPa; SD, 25.7 MPa) was used in the silanization step, and the lowest was obtained when 3isocyanatopropyltriethoxysilane + 1,2- bis-(triethoxysilyl)ethane (28.9 MPa; SD, 8.8 MPa) was used. The three-point bending strength was significantly affected by the functionality of the main silane tested (p 0.05). The composite that had been silanized with 3- isocyanatopropyltriethoxysilane had the greatest amount of water uptake (1.75%), and the composite silanized with 3-methacryloxypropyltrimethoxysilane + 1,2- bis-(triethoxysilyl)ethane had the least (1.08%). In conclusion, selection of the functional silane monomer can be a significant factor in developing filled resin composites in dentistry. © 2011 VSP.postprin

Effect of oral environment on new fiber-reinforced composites system

This journal suppl. entitled: Abstracts of the Academy of Dental Materials Annual Meeting, 9-12 October 2013 - Vancouver, BC, CanadaPURPOSE: Fiber-reinforced composite (FRC) consists of matrix that is reinforced with thin fibers, which have high tensile strength and flexural modulus (Zhang and Matinlinna, Silicon 4 (2012) 73). The bis-GMA-MMA combination is widely used as resin matrix, whereas bis-GMA is reported to be the most cytotoxic monomer among dental resin composite monomers (Moharamzadeh et al., Material 2 (2009) 514). Resin matrix 1,6-hexanediol dimethacrylate (HDMA) has similar reactive groups than bis-GMA, and is not listed among carcinogens (Vallittu and Sevelius, J Prosthet Dent 84 (2000) 13). The purpose of this study was to investigate the water sorption of a new resin matrix system of FRC based on HDMA. METHODS AND MATERIALS: Materials used were: E-glass fiber bundles (Stick Tech, Finland), HDMA (Esstech, USA), bis-GMA (Sigma–Aldrich, USA), MMA (ProSciTech, Australia), CQ (Esstech, USA) and CEMA (Esstech, USA). Fifteen specimens (2mm×2mm×25mm) were prepared and divided into 3 groups. Composition of group 1: 78.4%HDMA +19.6%MMA+ 1.0%CQ + 1.0%CEMA; group 2: 49.0%HDMA +49.0%MMA+ 1.0%CQ + 1.0%CEMA; and group 3: 78.4%bis-GMA +19.6%MMA+ 1.0%CQ + 1.0%CEMA. Specimens with two fiber rovings of 25mm long were placed in a mould and monomers were added and light-cured with halogen light-curing unit on both sides for 3×40 s. Specimens were immersed in 15 ml distilled water of 37 ◦C for 21 days. The difference in weights, before and after immersion were recorded. Data obtained were analyzed by one-way ANOVA and LSD. RESULTS: As for the difference in weights (before and after immersion), group 1 showed the lowest average (0.004%), followed by group 3 (0.003%) and group 2 (0.01%). Statistical analysis (ANOVA) proved a significant difference among the three groups (p 0.05). CONCLUSION: It can be concluded that FRC based on HDMA matrix system (group-1) is comparable to bis-GMA (group-3) on its water sorption.postprin