bisphenol-A Glycidyl Dimethacrylate Research Articles

In silico evaluation of stress distribution after vertebral body augmentation with conventional acrylics, composites and glass polyalkenoate cements

There exists clinical evidence of fractures in adjacent vertebrae subsequent to vertebral augmentation procedures, such as vertebroplasty (VP) and kyphoplasty (KP). A potential contributory factor to such fractures may be the excessive mismatch of mechanical properties between contemporary bone cements ( i.e. polymethyl methacrylate (PMMA) and bisphenol-a-glycidyl dimethacrylate (BIS-GMA)) and bone. Aluminum-free glass polyalkenoate cements (GPCs) present an interesting alternative to conventional bone cements. GPCs adhere to the philosophy that implant materials should have mechanical characteristics similar to those of the bone, and also offer chemical adhesion and intrinsic bioactivity. However, their influence on the loading patterns of augmented vertebrae (as compared with conventional bone cements) is not available in the literature. The present work investigates how the moduli of PMMA, BIS-GMA and GPC implants affect the stress distribution within a single, augmented vertebra, in both healthy and osteoporotic states. Using a finite element model of the L4 vertebra derived from computed tomography data, with simulated augmentation, it was found that, as cement stiffness increased, stress was redistributed from the cortical and trabecular bone to the cement implant. The GPC implant exhibited the least effect on stress redistribution in both the healthy and osteoporotic models compared to its acrylic counterparts. The significance of this work is that, under simulated physiological loading conditions, aluminum-free GPCs exhibit stress distribution throughout the vertebral body similar to that of the healthy bone. In comparison to conventional augmentation materials, the use of aluminum-free GPCs in VP and KP may help to ameliorate the clinical complication of adjacent vertebral body compression fractures.

Performance of melamine modified urea–formaldehyde microcapsules in a dental host material

AbstractUrea–formaldehyde (UF) microcapsules filled with dicyclopentadiene (DCPD) show potential for making self‐healing dental restorative materials. To enhance the physical properties of the capsules, the urea was partially replaced with 0–5% melamine. The microcapsules were analyzed by different microscopic techniques. DSC was used to examine the capsule shell, and the core content was confirmed by 1H NMR spectroscopy. Capsules in the range of 50–300 μm were then embedded in a dental composite matrix consisting of bisphenol‐A‐glycidyl dimethacrylate (Bis‐GMA) and triethylene‐glycol dimethacrylate (TEGDMA). Flexural strength, microhardness, and nanoindentation hardness measurements were performed on the light‐cured specimens. Optical microscopy (OM) examination showed a random distribution of the microspheres throughout the host material. The incorporation of small amounts of the microcapsules did not affect the performance of the matrix material. Scanning electron microscopy (SEM) analysis revealed excellent bonding of the microcapsules to the host material which is a characteristic of utter importance for maintaining the very good mechanical properties of a dental composite with self‐healing ability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.

In vitro orthodontic bracket bonding to porcelain

This in vitro study investigated the influence of using different combinations of bracket, adhesive, and light-curing source on the tensile bond strength to porcelain and on failure patterns at debonding. Tensile tests were performed using: one ceramic bracket versus one metal bracket, two orthodontic composites; type bisphenol A-glycidyldimethacrylate and urethane dimethacrylate (UDMA), and four light-curing units with the same range of emission spectrum but various light intensities: three light-emitting diode (LED) units and one halogen-based unit. One hundred and sixty porcelain samples were randomly divided into 16 equal groups. The porcelain surface was conditioned with 9 per cent hydrofluoric acid before silane application. The composite was photo-polymerized for 40 seconds. After storage in water at 37°C for 24 hours, the samples were subjected to tensile force until bond failure. Bond strength and bond failure mode were recorded; results were analysed (α = 0.05) using R language; linear model with constant variance for the bond strength and multinomial distribution for the failure mode. The bond strength in all groups was sufficient to withstand orthodontic treatment (>6 MPa). There was no statistical difference between the adhesives, but comparing bracket × light interaction, it was significantly higher with the ceramic bracket. No significant differences were seen between the metal bracket groups, but for the ceramic bracket, the results were significantly higher with the LED light. No fracture was observed in porcelain with the metal bracket but it occurred in 35 per cent of the ceramic bracket samples and the risk was higher when using UDMA composite and lower with LED high intensity light.

Fabrication and evaluation of Bis-GMA/TEGDMA resin with various amounts of silane-coated silica for orthodontic use

The objective of this research was to fabricate a composite with an optimum filler level in a bisphenol-A-glycidyldimethacrylate (Bis-GMA) triethylene glycidal dimethacrylate (TEGDMA) resin for bonding of metallic orthodontic brackets to achieve the best handling characteristics with optimum bond strength and without compromising the mechanical properties of the adhesive. One-hundred and sixty extracted human premolars free of any detectable pathology or buccal surface alterations were collected and divided into four groups. In group 1 (control), the teeth were bonded with stainless steel brackets using Transbond XT. In groups 2, 3, and 4, the teeth were bonded with metal brackets using a Bis-GMA/TEGDMA resin with 80, 60, and 20 per cent by weight silane-coated silica of a spherical shape with a mean size of 0.01 μm. Shear bond strength (SBS) of the composites was determined and the adhesive remnant index (ARI) and enamel fracture post-debonding were assessed. According to one-way analysis of variance and Tukey's honestly significant difference (HSD) multiple comparison tests, the SBS of group 4 (10.54 MPa) was considerably less than that of groups 1 (26.1 MPa), 2 (25.5 MPa), and 3 (24.6 MPa). Chi-square analysis revealed that there was an insignificant difference in the incidence of enamel fracture between groups 1 and 2, while a significant difference was present between groups 1 and 2 and 3 and 4. An insignificant difference was also observed in the location of the adhesive failure between the four groups. While all the bonding adhesives tested can be safely used for bonding of brackets, 60 per cent filled Bis-GMA/TEGDMA was superior clinically due to its ease of handling and superior bond strength.

Analysis of Organic Components Released from Dental Resin Composites in Saliva and Other Biological Fluids Using Chromatographic Techniques

Dental composites are tooth filling materials. Their chemical composition is complex since they are composed of synthetic polymers, ceramic reinforcing fillers, molecules, which promote or modify the polymerization reaction that yields the cross-linked polymer matrix from the dimethacrylate resin monomers, and silane coupling agents, which enable bonding of the reinforcing fillers to the polymer matrix. Each of these components is critical for a successful dental restoration. Residual monomers in the resin matrix such as triethylene glycol dimethacrylate (TEGDMA), Bis-phenol A glycidyl dimethacrylate (BIS-GMA), and urethane dimethacrylate (UDMA), additives and degradation products from resin-based dental restorative materials eluted into the oral cavity may influence the biocompatibility of these materials. The determination of compounds eluted from dental materials in biological fluids is of utmost importance and requires reliable quantification methods useful for studies addressing cytotoxic, genotoxic and estrogenic potential of these substances. In this review recent chromatographic methods developed for the determination: i.e. quantification and identification of components released from dental composites in saliva and other biological fluids will be presented.

Induction of DNA strand breaks by dental composite components compared to X-ray exposure in human gingival fibroblasts

The toxicity of dental composites has been attributed to the release of residual monomers from polymerized resin-based composites due to degradation processes or incomplete polymerization. Some of these eluted substances have a genotoxic potential. We tested the hypothesis that realistic concentrations (and/or worst case concentrations/situations) of bisphenol-A-glycidyldimethacrylate (BisGMA), triethyleneglycol dimethacrylate (TEGDMA), 2-hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) found in elution experiments can cause DNA strand breaks in human gingival fibroblasts (HGF). Such DNA damage was compared with that resulting from ionizing radiation coming from natural sources, dental radiography or tumor therapy. TEGDMA, HEMA and MMA did not induce DNA strand breaks at concentrations of up to 10mM. About 24h after incubation with 0.25mM BisGMA, significantly more DNA strand breaks were found in HGF compared to controls. DNA strand breaks caused by 0.25mM BisGMA, correspond to DNA strand breakage caused by irradiation with 4Gy, only used in the high single-dose irradiation tumor therapy. But 0.25mM BisGMA is more than 100-fold higher than that concentration found in worst case calculations. Therefore, our data did not support our hypothesis.

Excretion of dental resin monomers and metabolic intermediates via urine in guinea pigs

Objective Monomers like BisGMA (Bisphenol-A-glycidyldimethacrylate) and comonomers like TEGDMA (triethyleneglycoldimethacrylate) are used in dental restorative materials in order to build up the three-dimensional network of filling materials. Since earlier investigations revealed uptake and subsequent metabolism of unpolymerized remainders of (co)monomers, the present experiment investigates the metabolic urine pattern of guinea pigs ( n = 4) after application of TEGDMA or BisGMA (each dose = 0.02 mmol/kg body weight = 100%), respectively. Methods For the investigations BisGMA was pre-dissolved in DMSO and subsequently diluted with 0.9% NaCl solution (final DMSO concentration 1%) and TEGDMA was dissolved in 0.9% NaCl solution. The solutions were administered with a gastric tube into the animals. Control animals received either 0.9% NaCl or 0.9% NaCl solution with 1% DMSO solution. Results After 24 h in collected urine the following metabolites were identified. After administration of TEGDMA (mean relative concentration of administered substances) ± s.d. [%]; n = 4): unchanged TEGDMA: 12 ± 1.5%, MA: 2.4 ± 0.8%, and triethyleneglycol: 35 ± 2.2%. After administration of BisGMA (mean ± s.d. [%]; n = 4): unchanged BisGMA: 11.4 ± 2.7%, MA: 2.2 ± 0.6%, and bisphenol-A-bis(2,3-dihydroxypropyl)ether: 60.1 ± 5.2%). Conclusion No further metabolites like the previously identified intermediate 2,3-epoxymethacrylic acid and derived reaction products were identified in the urine, indicating that these metabolites must have reacted further.

Preparation and Evaluation of Dental Resin Luting Agents with Increasing Content of Bisphenol-A Ethoxylated Dimethacrylate

Resin luting agents in which bisphenol-A glycidyl dimethacrylate (Bis-GMA) and/or triethylene glycol dimethacrylate (TEGDMA) are replaced with increasing amounts of bisphenol-A ethoxylated dimethacrylate are prepared. Degree of conversion (DC), diametral tensile strength (DTS), Young's modulus (YM), Knoop hardness (KHN), film thickness (FT), water sorption (W(sp) ), and solubility are evaluated. Regression analyses investigate the substitution of each monomer. The most appreciable differences are detected when TEGDMA is replaced: decreased DC, DTS, and W(sp), and increased YM, KHN, and FT. For substitution of Bis-GMA, the only significant differences are reduced W(sp) and increased YM. An ideal formulation of resin cement would make use of the three monomers.

Low-shrinkage visible-light-curable urethane-modified epoxy acrylate/SiO 2 composites as dental restorative materials

In this study, low-shrinkage high-strength dental restorative materials were prepared and their properties were investigated. Epoxy acrylates modified with various stoichiometric amounts of urethane acrylates were used as the resin matrix and 3-(trimethoxysilyl)propyl methacrylate (MSMA)-modified monodisperse nano-sized SiO 2 particles were synthesized and used as the inorganic reinforcing filler. Polymer composites suitable for using as dental restorative materials were formed by curing the resin matrices containing MSMA-SiO 2 with visible-light. The viscosities of the obtained resin matrices, their polymerization shrinkages, hardness, flexural strengths, and flexural moduli of the obtained polymer composites were investigated. Compared with bisphenol-A/glycidyl dimethacrylate (Bis-GMA)-based dental restorative materials, the polymer composites obtained in this study exhibited greatly reduced degrees of shrinkage and better mechanical and physical properties.

Distribution and Excretion of BisGMA in Guinea Pigs

Bisphenol-A-glycidyldimethacrylate (BisGMA) is used in many resin-based dental materials. It was shown in vitro that BisGMA was released into the adjacent biophase from such materials during the first days after placement. In this study, the uptake, distribution, and excretion of [(14)C]BisGMA applied via gastric and intravenous administration (at dose levels well above those encountered in dental care) were examined in vivo in guinea pigs to test the hypothesis that BisGMA reaches cytotoxic levels in mammalian tissues. [(14)C]BisGMA was taken up rapidly from the stomach and intestine after gastric administration and was widely distributed in the body following administration by each route. Most [(14)C] was excreted within one day as (14)CO(2). The peak equivalent BisGMA levels in guinea pig tissues examined were at least 1000-fold less than known toxic levels. The peak urine level in guinea pigs that received well in excess of the body-weight-adjusted dose expected in humans was also below known toxic levels. The study therefore did not support the hypothesis.

Copolymerization kinetics of dental dimethacrylate resins initiated by a benzoyl peroxide/amine redox system

AbstractThe copolymerization of four dental dimethacrylates initiated by a benzoyl peroxide/4‐N,N‐dimethylamino phenethyl alcohol redox system at 37°C was studied with differential scanning calorimetry. The studied dimethacrylates were viscous bisphenol A glycidyl dimethacrylate (Bis‐GMA), bisphenol A ethoxylated dimethacrylate (Bis‐EMA), and urethane dimethacrylate (UDMA), which were characterized as base monomers, and low‐viscosity triethylene glycol dimethacrylate (TEGDMA), which was characterized as a diluent. Also, three series of dimethacrylate copolymers were prepared by incremental additions (12.5 wt %) of TEGDMA to a base comonomer (Bis‐GMA, UDMA or Bis‐EMA). The maximum rate of homopolymerization of the dimethacrylates followed the order of Bis‐GMA > UDMA > TEGDMA > Bis‐EMA, and the final degree of conversion of the corresponding homopolymers followed the order of TEGDMA > UDMA > Bis‐EMA > Bis‐GMA. A reaction–diffusion‐controlled termination region was clear in all monomers and started earlier in bulky and rigid Bis‐GMA and Bis‐EMA (followed by the more flexible UDMA and TEGDMA) but lasted longer in the Bis‐EMA polymerization. The maximum rate of copolymerization and degree of conversion of copolymers of a base monomer with TEGDMA changed monotonically with an increase in the TEGDMA content in the initial comonomer mixture. A synergistic effect was clear only in the final double‐bond conversion of Bis‐GMA/TEGDMA. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

The Curing Efficiency and Mechanical Properties of Light‐Activated Acrylic Resin

AbstractThe aim of this investigation was to determine degree of conversion, and flexural and compressive strength of photocurable acrylic resin. The acrylic resins based on bis‐phenol A glycidyl dimethacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA) were formulated and then irradiated with red light to form a solid crosslinked polymer. Various post curing conditions were studied to investigate their effects on curing efficiency. Degree of conversion was analyzed by means of Fourier Transform Infrared Spectroscopy (FTIR) to monitor the quantity of remaining acrylic double bond in the cured resin. Three‐point bending and compressive strength were tested using Universal Testing Machine (UTM) to evaluate the mechanical performance. Our investigation demonstrated that the formulated acrylic resins were possibly polymerized under irradiation with red light and degree of conversion and mechanical properties were closely correlated.

Thermal degradation of light-cured dimethacrylate resins: Part I. Isoconversional kinetic analysis

The thermal degradation of resins based on bis-phenol A glycidyl dimethacrylate (Bis-GMA), bis-phenol A ethoxylated dimethacrylate (Bis-EMA), urethane dimethacrylate (UDMA) and triethylene glycol dimethacrylate (TEGDMA) was investigated using thermogravimetric analysis. Four different heating rates were employed for its polymer in order to have adequate data to perform an isoconversional analysis. Activation energies were estimated as a function of the extent of degradation using a differential and an integral method. The observed differences were interpreted in terms of degradation mechanisms, which are highly depended on the structural characteristics of the corresponding resin. The existence of only a small number of defects in the network structure of Bis-GMA and Bis-EMA resins together with their stiff aromatic nuclei lead to the formation of a rigid network with high thermal stability and to decomposition in one-step. In contrast, inhomogeneities in the network structure of TEGDMA and UDMA resins, mainly due to the formation of primary cycles during polymerization, result in a two-step degradation mechanism at much lower temperatures. The hydrogen bonding ability of Bis-GMA and UDMA monomer units was also found to play an important role during thermal degradation of these resins.

Comparison of an experimental bone cement with surgical Simplex® P, Spineplex® and Cortoss®

Conventional polymethylmethacrylate (PMMA) cements and more recently Bisphenol-a-glycidyl dimethacrylate (BIS-GMA) composite cements are employed in procedures such as vertebroplasty. Unfortunately, such materials have inherent drawbacks including, a high curing exotherm, the incorporation of toxic components in their formulations, and critically, exhibit a modulus mismatch between cement and bone. The literature suggests that aluminium free, zinc based glass polyalkenoate cements (Zn-GPC) may be suitable alternative materials for consideration in such applications as vertebroplasty. This paper, examines one formulation of Zn-GPC and compares its strengths, modulus, and biocompatibility with three commercially available bone cements, Spineplex, Simplex P and Cortoss. The setting times indicate that the current formulation of Zn-GPC sets in a time unsuitable for clinical deployment. However during setting, the peak exotherm was recorded to be 33 degrees C, the lowest of all cements examined, and well below the threshold level for tissue necrosis to occur. The data obtained from mechanical testing shows the Zn-GPC has strengths of 63 MPa in compression and 30 MPa in biaxial flexure. Importantly these strengths remain stable with maturation; similar long term stability was exhibited by both Spineplex and Simplex P. Conversely, the strengths of Cortoss were observed to rapidly diminish with time, a cause for clinical concern. In addition to strengths, the modulus of each material was determined. Only the Zn-GPC exhibited a modulus similar to vertebral trabecular bone, with all commercial materials exhibiting excessively high moduli. Such data indicates that the use of Zn-GPC may reduce adjacent fractures. The final investigation used the well established simulated body fluid (SBF) method to examine the ability of each material to bond with bone. The results indicate that the Zn-GPC is capable of producing a bone like apatite layer at its surface within 24 h which increased in coverage and density up to 7 days. Conversely, Spineplex, and Simplex P exhibit no apatite layer formation, while Cortoss exhibits only minimal formation of an apatite layer after 7 days incubation in SBF. This paper shows that Zn-GPC, with optimised setting times, are suitable candidate materials for further development as bone cements.

BisGMA/TiO2 Organic-Inorganic Hybrid Nanocomposite

BisGMA (Bisphenol-A-glycidyldimethacrylate) resin had been modified by incorporating TiO2 nanoparticles (0.5–2% by weight). An ultrasonic mixing process was used to disperse the particles into the resin system prior to casting and curing test specimens. TEM investigation showed that the particles were nano size (5–60 nm) and dispersed throughout the entire volume of the resin. In dynamic mechanical analysis, nanophase resin showed increase in storage modulus and glass transition temperature from neat resin system. Thermogravimetric analysis revealed better thermal stability. Flexural loading, T g and flexural modulus of the nanocomposites were enhanced as the particle volume fraction was enhanced and than decreased.

Synthesis, purification and curing studies of vinyl ester network

PurposeThis paper seeks to prepare and characterise vinyl ester (bisphenol‐A‐glycidyldimethacrylate (BisGMA)) prepolymer via a new synthetic route by the esterification of methacrylic acid and epoxy resinDesign/methodology/approachBisGMA prepolymer was synthesised from methacrylic acid and diglycidyl ether of bisphenol‐A (BPA) type epoxy resin. The synthesised compound was then purified and characterised.FindingsBisGMA prepolymer was synthesised from methacrylic acid and diglycidyl ether of BPA‐type epoxy resin using triphenylphosphine as a catalyst and hydroxytoluene as a stabiliser. The synthesised compound was then purified by normal phase liquid chromatography and was analysed by proton NMR and reverse phase HPLC. The cure kinetics of the purified resin were investigated by differential scanning calorimetry using NETZSCH thermokinetics software.Research limitations/implicationsThe preparation, purification and kinetics study of the prepolymer described in the present investigation may be useful for preparation, purification and kinetics study of the other vinyl esters by a new synthetic route. Also, the polymers supports based on bisphenol‐A‐glycidyldimethacrylate have acceptable mechanical properties, chemical stability and are suitable for dental restoratives, fissure sealants, coatings, adhesives, moulding compounds, structural laminates, electrical applications and military/aerospace applications.Practical implicationsThe method for the preparation, purification and kinetics study of the prepolymer is simple and the above method provides a simple and practical solution for some other vinyl esters.Originality/valueThis is a novel method for synthesis and purification of BisGMA and may be useful for the synthesis and purification of other vinyl esters.

Toxicity potentiation by H2O2 with components of dental restorative materials on human oral cells

Toxicity potentiation of two monomers [bisphenol-A-glycidyldimethacrylate (BisGMA) and urethanedimethacrylate (UDMA)] as well as two comonomers [triethyleneglycoldimethacrylate (TEGDMA) and 2-hydroxyethylmethacrylate (HEMA)], each in combination with H(2)O(2), was investigated on the viability on human gingival fibroblasts (HGF) and human pulpal fibroblasts (HPF). The applied concentration of H(2)O(2) was 0.06 or 0.1 mmol/l, respectively, corresponding to the EC(0) of H(2)O(2) in HGF or HPF. The cell viability was assessed by the XTT test. From this test the half maximum effect concentrations (EC(50)) were calculated from fitted sigmoidale curves. EC(50) values were (HGF; mmol/l; mean +/- s.e.m.; n = 5): HEMA 11.9 +/- 0.9, TEGDMA 3.7 +/- 0.3, H(2)O(2) 0.36 +/- 0.04, UDMA 0.27 +/- 0.08, and BisGMA 0.11 +/- 0.03. No significant (P < 0.05) differences in the EC(50) values were observed when HGF was exposed to substances, as compared to HPF. No significant decrease of the EC(50) values was found when HGF or HPF, respectively, was exposed to HEMA or BisGMA in addition with H(2)O(2) up to the concentration of 0.1 mmol/l, as compared to those EC(50) values of each compound without H(2)O(2) addition. A significant decrease of the TEGDMA EC(50) value from 3.7 to 2.1 or 0.4 mmol/l, respectively, was found when cells were exposed to TEGDMA in combination with H(2)O(2) (0.06 or 0.1 mmol/l), as compared to that TEGDMA EC(50) value without H(2)O(2) addition. A significant decrease of the UDMA EC(50) value from 0.27 to 0.11 or 0.08 mmol/l, respectively, was found when HGF or HPF was exposed to UDMA in combination with H(2)O(2) (0.06 or 0.1 mmol/l), as compared to that UDMA EC(50) value without H(2)O(2) addition. The addition of H(2)O(2) (0.06 or 0.1 mmol/l) resulted in a toxicity potentiation of TEGDMA and UDMA, but not of HEMA and BisGMA, on HGF or HPF.

Synthesis, purification and curing properties of vinyl ester network

PurposeTo prepare and characterise vinyl ester (Bisphenol‐A‐glycidyldimethacrylate (BisGMA)) prepolymer via a new synthetic route involving the esterification of methacrylic acid and epoxy resin.Design/methodology/approachBisGMA prepolymer was synthesised from methacrylic acid and diglycidyl ether of bisphenol‐A‐type epoxy resin. The compound synthesised was then purified and characterised.FindingsBisGMA prepolymer was synthesised from methacrylic acid and diglycidyl ether of bisphenol‐A‐type epoxy resin using triphenylphosphine as a catalyst and hydroxy toluene as a stabiliser. The synthesised compound was then purified by normal phase liquid chromatography and was analysed by proton NMR and reverse phase HPLC. The cure kinetics of the purified resin was investigated by differential scanning calorimetry (DSC) using NETZSCH thermo kinetics software.Research limitations/implicationsThe preparation, purification and kinetics study of the prepolymer described in the present investigation may be useful for preparation, purification and kinetics study of the other vinyl esters by a new synthetic route. Also, the polymer supports based on BisGMA have acceptable mechanical properties, chemical stability and are suitable for dental restoratives, fissure sealants, coatings, adhesives, moulding compounds, structural laminates, electrical applications and military/aerospace applications.Practical implicationsThe method for the preparation, purification and kinetics study of the prepolymer is simple and provides a simple and practical solution for some other vinyl esters.Originality/valueThis is a novel method for synthesis and purification of BisGMA and may be useful for the synthesis and purification of other vinyl esters.

Nonylphenyl methacrylate modified bisphenol‐a‐glycidyl dimethacrylate(BisGMA) networks

PurposeTo evaluate the performance of a reactive diluent, nonylphenyl methacrylate (NPM) for toughness improvement of bisphenol‐a‐glycidyl dimethacrylate (BisGMA) and to optimise the results of such a modification.Design/methodology/approachTo achieve desirable rheological and physico‐mechanical properties of BisGMA/NPM network, various compositions were made by incorporating different concentrations of NPM. The effect of concentration on the impact and the adhesive strengths of the unmodified and modified BisGMA networks were characterised.FindingsThe modification of BisGMA resin using NPM showed significant enhancement of the impact and the adhesive strengths over the unmodified one. The modification caused a chemical linkage between NPM and BisGMA resin, which led not only to a phase separation but also to establishing the intrinsically strong chemical bonds across the NPM phase/resin matrix interphase, which was responsible for the improvement of the impact and adhesive strength. The optimum results were obtained at 10/h (parts per 100 parts of BisGMA resin) of modifier.Research limitations/implicationsThe reactive diluent, used in the present context was synthesised from nonyl phenol, methacrylic acid and benzoyl chloride in methyl ethyl ketone using triethylamine as base.Practical implicationsThe method of modification developed provides a simple and practical solution for improving the rheological and physico‐mechanical properties of BisGMA network.Originality/valueThe method developed is a novel one for enhancing the rheological and physico‐mechanical properties of BisGMA network diluted with NPM resin and may find numerous applications in surface coating and adhesive.

Identification of organic extractables from commercial resin-modified glass-ionomers using HPLC-MS

Elution of organic compounds from resin-based dental fillings during their application in the human mouth environment may have a potential impact on the human health. Ethanol, water and other solvents very often present in the human mouth have the ability to penetrate dental fillings placed in the human tooth. Penetration of liquids into the tooth may lead to the liberation of unreacted dental filling ingredients or their degradation products. Determination of these compounds is necessary for better knowledge from possible harmful effects caused by dental fillings. The aim of this study was the isolation and identification of compounds released from resin-modified glass-ionomer cements (RMGICs), resin-based dental materials applied in dentistry. Compounds were extracted from fillings by using four solvents (40% ethanol, water, 1% acetic acid and artificial saliva). Liquid samples containing eluted compounds were then extracted, evaporated and analyzed by using of HPLC-MS (high-performance liquid chromatography-mass spectrometry) and HPLC-DAD (high-performance liquid chromatography-diode array detection) techniques. Almost thirty components (monomers and additives) of RMGICs were identified. The main identified extractables were: Bis-GMA (bisphenol A glycidyl dimethacrylate), Bis-EMA (ethoxylated bisphenol A dimethacrylate), UDMA (urethane dimethacrylate), TEGDMA (triethylene glycol dimethacrylate), HEMA (2-hydroxyethyl methacrylate) as monomers and diphenyliodonium chloride, camphorquinone (initiators), BHA (inhibitor), 4-(dimethylamino) ethyl benzoate (co-initiator) as additives.