Bis-GMA Research Articles

The implementation of image analysis for the visualization of adhesion assessment of a composite film

The objective of this study is to investigate quantitative assessment of the adhesion behavior of composite films onto a metallic surface. The composite films had UV cured Bis-GMA (Bisphenol A glycidylmethacrylate)/TEGDMA (triethylene glycol dimethacrylate) as matrix and ferrous oxide doped alumina (Al2O3 Fe) particles with two surface modifications, (3-methacryloxypropyltrimethoxysilane) (MEMO) and the vinyltris(2-methoxyethoxy)silane (VTMOEO), as reinforcement. Composites were made with 0.5, 1.5 and 3 wt% of alumina particles. Adhesion was evaluated using the micro hardness testing method. The contact angle was measured and compared to the adhesive parameter from micro hardness measurements. The form of the indent on the surface of the composite film was analyzed in order to correlate the indent morphology to the adhesion quality.

BisGMA analogues as monomers and diluents for dental restorative composite materials

Current commercially available dental composite materials have certain limitations for their use, including high monomer viscosity and high polymerization shrinkage, resulting in residual stresses and interfacial gaps. This study focused on the chemical modification of resin monomer bisphenol A-glycidyl methacrylate (bisGMA), so as to reduce the viscosity and polymerization shrinkage. In this design, the hydroxyl groups of bisGMA were transformed into ester groups with various alkyl chain length and branching. The modified monomers showed promising properties including reduced viscosity, reduced polymerization shrinkage, increased hydrophobicity, increased degree of double bond conversion, and improved mechanical properties of the resulting dental resin composites. The structure/property relationships of the new monomers were investigated, and optimal monomer structures were identified for dental composites with improved properties.

Ispitivanje adhezije polimernih kompozitnih filmova na bazi Bis-GMA/TEGDMA na različitim metalnim podlogama

The subject of this study is the quantitative adhesion of a UV-curing composite film based on Bis-GMA (Bisphenol A glycidylmethacrylate) / TEGDMA (triethylene glycol dimethacrylate) as a matrix and particles doped with ferrous oxide on a metal substrate. Two different metal substrates: silver and gold-spattered brass with nickel intermediate coating were used in adhesion evaluating. Adhesion was measured using micro-identation and it was compared with the measured wetting angle of composites to the substrate. It has been shown that the substrates, although with similar mechanical properties that are reflected in very close hardness values, differ by achieved adhesive bonding with the polymer UV-cured polymer film. The addition of ceramic particles in the polymer matrix increased the adhesion of the composite film to both substrates, but the adhesion trend was dependent on the substrate type.

Improvement of cavitation resistance of composite films using functionalized alumina particles

Composite films having the UV cured Bis-GMA (Bisphenol A glycidylmethacrylate)/TEGDMA (triethylene glycol dimethacrylate) as a matrix and the ferrous oxide doped alumina (Al2O3 Fe) based particles were prepared and subjected to cavitation. In order to improve the mechanical and adhesion properties of composites, four different surface modifications of filler particles were performed: 3-methacryloxypropyltrimethoxysilane (MEMO), vinyl-tris(2-methoxyethoxy)silane (VTMOEO), (3-aminopropyl)trimethoxysilane (APTMS) and biodiesel (BD). Composite films were made with 0.5, 1.5, and 3 wt.% of ferrous oxide doped alumina particles with each of the mentioned surface modifications. Composite films were prepared on brass substrates and exposed to cavitation erosion. The erosion was monitored using the mass loss while image analysis was used to observe surface defects. The composite film reinforced with Al2O3 Fe having VTMOEO as a surface modifier was the most resistant one in terms of mass loss, as well as the level of surface destruction. Results were compared to the same polymer matrix film and composite films prepared with fillers without surface modifications revealing that all composites with surface modified fillers exhibited some improvement in resistance to cavitation.

Adhesion testing of composites based on Bis-GMA/TEGDMA monomers reinforced with alumina based fillers on brass substrate

Abstract Quantitative assessment of the adhesion behavior between the composite film having UV cured Bis-GMA (Bisphenol A glycidylmethacrylate)/TEGDMA (triethylene glycol dimethacrylate) as matrix and the aluminum oxide based particles as a reinforcement on metallic surface was done using the microhardness testing method and compared to the contact angle. Composites are made with 1 wt %, 3 wt %, 5 wt % and 10 wt % of alumina based fillers. Films were subjected to the cavitation in order to evaluate the erosion resistance of the composite film on the metal. It is proved that the adhesion is improved with addition of the fillers while the cavitation resistance is improved up to 5 wt % of fillers.

Synthesis of the bio-based alternative to Bis-GMA and its application to photo-polymerizable adhesives

Photo-polymerizable compound with isosorbide core attached by glycidyl methacrylate (Iso-GMA) was synthesized from bio-based isosorbide via two step reactions to replace bisphenol A-glycidyl methacrylate (Bis-GMA), and its photo-polymerizing behaviors and mechanical properties after photo-polymerization were investigated. The viscosity of Iso-GMA was lower than that of Bis-GMA, and the glass transition temperature (Tg) of photo-polymerized Iso-GMA was relatively high (80.5°C) although there was no aromatic moiety in the molecule. The photo-polymerizing pattern of Iso-GMA was analyzed by photo-DSC and FTIR, and it showed a similar photo-polymerizing rate to Bis-GMA/triethylene glycol dimethacrylate (TEGDMA) composition (6:4, w/w). The shrinkage ratio of Iso-GMA during photo-polymerization was less than that of Bis-GMA/TEGDMA (5% vs 7.2%). In addition, the adhesion properties, compressive strength, and flexural properties of photo-polymerized Iso-GMA were comparable to those of Bis-GMA/TEGDMA. Bio-based Iso-GMA could be a feasible alternative to problematic Bis-GMA that widely used in a variety of applications.

Radiopaque dental adhesive with addition of niobium pentoxide nanoparticles

Radiopacity is an important property of dental adhesives, because it allows the adhesive resin to be in contrast with the tooth structure and other restorative materials. This study aimed to develop a radiopaque experimental adhesive resin through the addition of niobium pentoxide (Nb2O5) particles. The effects of adding different concentrations of Nb2O5 nanoparticles synthesized by microwave-assisted hydrothermal synthesis (MHS) were compared to the commercial Nb2O5 microparticles. The experimental adhesive resin was formulated by mixing bisphenol A glycidyl methacrylate (Bis-GMA), 2-hydroxyethyl methacrylate (HEMA), camphorquinone (CQ) and ethyl 4-(dimethylamino)benzoate (EDAB). Experimental adhesive resins were evaluated by the radiopacity, degree of conversion, Knoop microhardness, translucency parameter, depth of cure, viscosity, and sedimentation rate. Synthesized Nb2O5 showed hexagonal structure and nanoneedles aggregates in form of nanoflowers. The incorporation of Nb2O5 nanoparticles into the dental adhesive resin showed high dispersion stability and improved the radiopaque properties.

Biodegradation Studies of Novel Fluorinated Di-Vinyl Urethane Monomers and Interaction of Biological Elements with Their Polymerized Films.

The monomeric components of resin composites in dental restorative materials are susceptible to hydrolysis in the oral cavity. The main objective of this study was to assess the bio-stability of fluorinated urethane dimethacrylates and determine the nature of fluoro-chemistry interactions with protein and bacterial adhesion (both sources of hydrolytic activity) onto cured resin. Degradation studies were performed in the presence of either albumin (in a mildly alkaline pH) or cholesterol esterase (CE). The surface chemistry of the polymers was assessed by water contact angle measurements, pre- and post- incubation with albumin. Adhesion of Streptococcus mutans to cured resin was investigated. The fluorinated monomers were more stable against degradation when compared to the commercial monomer bisphenol A-diglycidyl methacrylate (BisGMA). While fluorinated monomers showed hydrolytic stability with respect to CE, all fluorinated monomers underwent some degree of degradation with albumin. The fluoro-chemistry did not reduce protein and/or bacterial adhesion onto the surface, however post incubation with albumin, the fluorinated surfaces still presented hydrophobic character as determined by the high contact angle values ranging from 79° to 86°. These monomers could potentially be used to increase the hydrophobicity of polymeric composites and provide a means to moderate esterolytic degradation associated with the monomeric component of the polymers within the oral cavity.

Improvements in self-curing composites

PurposeThe purpose of this study was to test the influence of a barbituric acid derivative acting as a catalyst and small amounts of pyrolytic silica in acrylic resins on color stability, solubility and sorption of a composite. Materials and methodsA series of two-component powder/liquid resin systems were prepared. Monomer-like mixtures (bis-GMA, TEGDMA, tertiary amine 60/40) and a quartz powder with additions of various silica and barbituric acid derivatives were used. Temperature of the material during polymerization was measured with the use of a thermometer. In addition, the material’s flexural and compressive strength, sorption and solubility were tested pursuant to ISO4049:2009. ResultsThe powder-based acrylic composition in a liquid mixed immediately before use, after an addition of a 0.5% barbituric acid derivative, has a lower temperature during the polymerization process (a reduction from 43°C to 37°C), whereas color stability over time is improved, with ΔE=1.81 for samples of powder mixtures containing between 0.45% of BPO and 0.15% of barbituric acid derivatives. For silanized quartz powder with 0.55% BPO and 0.1% BA+0.5% Aerosil R711, the obtained sorption value was 4.57±0.22μg/mm3, whereas solubility was 1.60±0.32μg/mm3. ConclusionsNew catalytic system with barbituric acid derivative, improves color stability for samples stored at room condition and under light of high intensity. A two-phase composite (bis GMA TEGDMA/Quartz), with a new catalytic system with barbituric acid derivatives, has a lower self-cured temperature. Adding a small quantity of hydrophobic silica (0.5%) has a significant influence, with reduced sorption and solubility of the material.

Property enhancement of dental composite prepared with an isosorbide-based photocurable compound by mixing with TEGDMA

We synthesized isosorbide glycidyl methacrylate (IsoGMA) as a bio-based analog of bisphenol A-glycidyl methacrylate (BisGMA) and investigated the mechanical and physical properties of IsoGMA-based dental composites to examine the possibility of using IsoGMA as a less-toxic substitute for BisGMA. The dental composites that were prepared with IsoGMA exhibited a low flexural strength compared to that of the BisGMA-based composites due to the high viscosity and surface energy of IsoGMA. After mixing with tri(ethylene glycol) dimethacrylate (TEGDMA), IsoGMA/TEGDMA (8:2) composites exhibited a flexural strength of 120MPa and a glass transition temperature of 96.9°C, which were higher than those of the IsoGMA composite (i.e., 79.0MPa and 65.1°C, respectively). In addition, TEGDMA improved the water sorption of the IsoGMA composite from 28.0 to 22.2μg/mm3, but slightly increased the curing shrinkage from 3.4 to 4.0%.

Unbound monomers do diffuse through the dentin barrier

ObjectivesAssessing the role of dentinal fluid proteins in trans-dentinal diffusion of free monomers in vitro. MethodsAn artificial pulp chamber (APC) topped human dentin disks was used. A simplified two-step etch-and-rinse adhesive was formulated with 2-hydroethyl-methacrylate (HEMA), Bisphenol-A-diglycidyl-methacrylate (BisGMA), using Camphorquinone/tertiary amine as initiators. Two extraction media were used: buffered saline (Control), buffered saline with 1% bovine serum albumin (BSA). Samples were acid-etched, rinsed, air dried. Simplified primer was used, adhesive applied then light cured with a LED curing. Monomer diffusion was assessed by reverse phase HPLC. ResultsQuantifiable amounts of HEMA were detected in both extraction media while BisGMA was present in quantifiable amounts in BSA medium only. Diffused monomers concentrations were significantly higher for both monomers in BSA extraction medium. SignificanceAlbumin is sometimes referred to as taxi protein for its ability to bind and transport hydrophobic ligands. From our results, we hypothesized that albumin can also transport unbound monomers released from dental adhesive through the dentin barrier. However, dentinal fluid proteins like albumin could have significant effect on monomer diffusion through dentin to the dental pulp transporting highly hydrophobic molecules like BisGMA and enhancing diffusion of more hydrophilic ones like HEMA. These results demonstrate a new possible mechanism for cytotoxicity of resin monomers.

불소 지속방출 및 생체적합성을 가진 불소 바니쉬의 개발

The purpose of this study was to fabricate a biocompatible fluoride varnish with sustained fluoride release, and to compare it with commercial fluoride varnishes. For the experimental fluoride varnish, bis-GMA (BG) or two types of rosin (KR-610: K0, KR-612: K2) were used as bases. Either ethyl acetate or ethanol was added as solvent and 5 wt% NaF was used. 5 mg of experimental F- varnishes and 2 commercial products, Cavity shield (CS) and Flor-opal (FO), were applied on a labial surface of bovine teeth (10 mm × 7 mm). The amount of fluoride release was measured at 1 hr, 2 hrs, 3 hrs, 4 hrs, 8 hrs, 12 hrs, 1 day, 3 days, 5 days, 10 days, 15 days, 20 days and 30 days. MTT test was done with diluted F- varnishes using ethanol. Statistical analysis was done with one-way ANOVA and Duncan multiple range test (α=0.05). BG showed the highest fluoride release at 1 hr (P0.05), while that of K0 was highest at 2 hrs (P0.05). From 1 day to 5 days, experimental fluoride varnishes showed higher fluoride release than the commercial products (P0.05), and there were no significant differences after 5 days (P0.05). For MTT test, K0 and FO showed higher cell viability than other experimental groups (P0.05), with no significant differences with K2 (P0.05). Considering the sustained fluoride release and cell viability of the experimental rosin-based fluoride varnishes compared with commercial products, it will be appropriate for clinical application.

Fluorinated bis-GMA as potential monomers for dental restorative composite materials

Bisphenol A-glycidyl methacrylate (bisGMA) is one of the most widely used monomers in the preparation of dental restorative composite resins. However, this monomer has high viscosity and high hydrophilicity, leading to high volume shrinkage and high water content of the resulting dental restoratives after polymerization. We hypothesized that the viscosity and hydrophilicity could be dramatically reduced by transforming the hydroxyl groups of bisGMA into fluorinated esters. To test this hypothesis, we synthesized a new fluorinated bisGMA analogue (perFB-bisGMA) through the esterification of bisGMA with perfluorobutyryl chloride. The chemical structure of perFB-bisGMA was confirmed by NMR and FTIR studies. PerFB-bisGMA had a much lower viscosity and much higher hydrophobicity than bisGMA. BisGMA and perFB-bisGMA were copolymerized through light-initiated polymerization. With the increase of perFB-bisGMA content, the mechanical properties of the copolymers were not negatively affected, yet the polymerization shrinkage was reduced, and the hydrophobicity of the copolymer was increased, suggesting that fluorinated esters of bisGMA could be attractive candidates to copolymerize with bisGMA for dental restorative applications.

Cytotoxicity and genotoxicity of a low-shrinkage monomer and monoacylphosphine oxide photoinitiator: Comparative analyses of individual toxicity and combination effects in mixtures

ObjectiveTo compare cytotoxicity and genotoxicity of novel urethane-based monomer FIT-852 and monoacylphosphine oxide photoinitiator (Lucirin TPO) with conventional Bisphenol A-glycidyl-methacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA) monomers and camphorquinone (CQ)/amine photoinitiator system, respectively. Moreover, we quantified and analyzed the combinatorial effects of individual substances in resin-based mixtures concerning the nature of the combinatorial effects. MethodsCytotoxic and genotoxic effects of BisGMA, FIT, TEGDMA, CQ, DMAEMA and TPO and their combined toxicity in four clinically relevant mixtures (FIT/TPO, FIT/CQ, BisGMA/TPO, BisGMA/CQ) were tested on human fetal lung fibroblasts MRC-5 using MTT and Comet assays. We assessed combination effects of monomers and photoinitiators on overall toxicity from the measured concentration-effect relationships. Combination index (CI) was calculated on the basis of the median-effect equation derived from the mass-action law principle. ResultsIndividual substances showed decreasing cytotoxic effects in the following order: BisGMA>TPO>FIT>CQ>DMAEMA>TEGDMA. Experimental mixtures showed decreasing cytotoxic effects in the order BisGMA/TPO>BisGMA/CQ>FIT/CQ>FIT/TPO. FIT-based mixtures exhibited antagonistic cytotoxic effects between components while BisGMA-based mixtures demonstrated synergistic effects at ED50. TPO amplified both antagonistic and synergistic cytotoxic effects in mixtures. Pure substances showed genotoxicity in the following order: TPO>BisGMA>FIT>CQ>TEGDMA. We did not detect the genotoxic potential of DMAEMA. The rank of genotoxic concentrations of the mixtures was: BisGMA/TPO>BisGMA/CQ>FIT/CQ>FIT/TPO. SignificanceLower cytotoxicity and genotoxicity of FIT than BisGMA suggests its greater biocompatibility. Conversely, photoinitiator TPO was significantly more cytotoxic and genotoxic than both CQ and DMAEMA. CI values showed that components of FIT-based mixtures exhibit an antagonistic cytotoxic effect, while compontents of BisGMA-based mixtures show synergism.

Synthesis and characterization of a novel resin monomer with low viscosity

ObjectiveIn this study, we designed and synthesized a novel macromolecule (tetramethyl bisphenol F acrylate, TMBPF-Ac) with low viscosity, excellent mechanical properties, and good biocompatibility. It could be used as a monomer for dental resin composites, which could reduce the risk of human exposure to bisphenol A derivatives in the oral environment. In addition, the monomer could be used without diluent, thereby avoiding the negative effect of a diluent MethodsTMBPF-Ac was synthesized by a multistep condensation reaction. Its structure was confirmed by 1H NMR spectra. Different resin mixtures were prepared, and then a number of performance and cytotoxicity tests were performed on these specimens. Results1H NMR spectra showed that the structure of TMBPF-Ac was in accordance with the design. The viscosity of TMBPF-Ac was obviously lower than that of bisphenol-A diglycidyl methacrylate. The three kinds of resins used in this study were in line with ISO 4049:2009 and ISO 10993-5:2009. TMBPF-Ac-based resin had better physical and biological properties.

Dysfunctional Uterine Bleeding Following Treatment with Bisphenol-A Glycidyl Methacrylate (BisGMA) Dental Resins

Objective: Bisphenol-A (BPA) is a xenoestrogen used in many consumer products. Here we present a case of dysfunctional uterine bleeding after exposure to dental sealant containing BPA. Design: Case Report Setting: Academic Medical Center Intervention: Dysfunctional uterine bleeding was diagnosed, and no therapy was initiated. Results: The patient continued to experience bleeding following each exposure. Conclusion: Female patients undergoing dental procedures that use BPA containing compounds may experience dysfunctional bleeding.

Novel urethane-based polymer for dental applications with decreased monomer leaching

The aim of this study was to synthesize and characterize new multifunctional-urethane-methacrylate monomers to be used as the organic matrix in restorative dental composites, and evaluate the main physical-chemical properties of the resulting material. Bis-GMA (bisphenol-A-diglycidylmethacrylate) and GDMA (glycerol dimethacrylate) were modified by reacting the hydroxyl groups with isocyanate groups of urethane-methacrylate precursors to result in the new monomeric systems U-(bis-GMA)-Mod and U-(GDMA)-Mod, U=Urethane and Mod=Modified. The modifications were characterized by FTIR and 1H NMR. The final monomeric synthesized system was used to prepare dental resins and composites. The physical-chemical properties were evaluated and compared with those of bis-GMA composites with varying filler contents or unfilled resins. U-(bis-GMA)-Mod and U-(GDMA)-Mod can be used to prepare dental restorative composites, with some foreseeable advantages compared with bis-GMA composites. One significant advantage is that these composites have the potential to be less toxic, once they presented a reduction of 50% in leaching of unreacted monomers extracted by solvent.

A low migration phosphine to overcome the oxygen inhibition in new high performance photoinitiating systems for photocurable dental type resins

AbstractThe objective of this work was to propose a novel low migration additive (i.e. a phosphine) to overcome the oxygen inhibition in a camphorquinone (CQ) base photoinitiating system for the polymerization of methacrylates (e.g. a bisphenol A‐glycidyl methacrylate (Bis‐GMA)/triethyleneglycol dimethacrylate (TEGDMA) blend (70%/30% w/w)) upon exposure to a commercial blue light emitting diode centred at 477 nm. CQ/amine/phosphine derivative or CQ/amine/iodonium salt/phosphine derivative combinations were studied. Real‐time Fourier transform IR and photo‐DSC experiments were used to monitor the polymerization profiles. Remarkably, it was found that the addition of the new phosphine derivative to CQ/amine or CQ/amine/iodonium salt noticeably improved the rate of polymerization and the final conversion in air. A low migration was found for this additive as shown by HPLC experiments in agreement with a copolymerizable behaviour. No additional yellowing of the film was observed. Electron spin resonance spectrometry was used to detect the produced radicals. The overall chemical mechanisms are investigated and discussed. © 2016 Society of Chemical Industry

A novel photoinitiating system producing germyl radicals for the polymerization of representative methacrylate resins: Camphorquinone/R3GeH/iodonium salt

ObjectivesThe aim of our study is to find an amine free photoinitiating system (PIS) for the polymerization of representative dental methacrylate resins. A photoinitiating system (PIS) based on camphorquinone (CQ)/triphenylgermanium hydride/diphenyl iodonium hexafluorophosphate is proposed and compared to the conventional CQ/amine couple. The polymerization monitoring of thin (∼20μm) and thick (1.4mm) samples of a bisphenol A-glycidyl methacrylate (Bis-GMA)/triethyleneglycol dimethacrylate (TEGDMA) blend (70%/30% w/w) and of a urethane dimethacrylate (UDMA) upon exposure to a commercial blue LED centered at 477nm under air or in laminate is described. Finally, the impact of the photoinitiating system composition on the final polymer color is evaluated in detail. MethodsFTIR and DSC experiments are used to record the photopolymerization profiles. ESR spectrometry and steady state photolysis are used to detect the produced radicals. Color measurements are carried out to determine the key parameters in the bleaching of the different dental formulations. ResultsThe efficiency of the newly proposed PISs for the photopolymerization of BisGMA/TEGDMA and UDMA for thin (20μm) or for thick (1.4mm) samples upon exposure to a dental blue LED under air is excellent. It is noticeably higher than that of the CQ/amine reference couple. Excellent bleaching properties are also observed under irradiation in presence of the new PISs. A good correlation is found between the sample bleaching and the amount of Ph3GeH in the formulation. The excited state processes could be established. The overall chemical mechanisms for the initiation step were also clarified.

The in vitro wear behavior of nanozirconia-filled dental composite in food slurry condition

The purpose of this investigation was to analyze the effect of adding different weight fraction of nanozirconia on wear characteristics of resin-based dental composite. The dental composites were fabricated by adding (0–3 wt.%) of silane-modified nanozirconia particles into a monomer system (50 wt.% bisphenol-A glycidyl methacrylate, 49 wt.% tri-ethylene glycol dimethacrylate, 0.2 wt.% Camphorquinone, and 0.8 wt.% ethyl 4 dimethyl amino benzoate). The experiments were conducted based on steady state condition and Taguchi’s orthogonal design in a dental wear simulator. A theoretical model was proposed for wear assessment and validated with the experimental results. The findings of the experiments indicated that the composite with 3 wt.% nanozirconia demonstrated lowest volumetric wear rate.