Bisphenylglycidyl Dimethacrylate Research Articles

Synthesis and Characterization of New Dental Composite for Dentistry Based on Unsaturated Monomers and Nano-fillers by Photopolymerization

In this study, dental nano-composite specimens were prepared by dispersion of various amounts of nano-sized fillers (HA, ZrO2, and SiO2) in a monomer system containing 60% Bis-GMA and 40% TEGDMA. 2,2 propyl bis-phenyl glycidyldimethacrylate (Bis-GMA) with unsaturated monomers were prepared. Camphor Quinone (CQ) of 1 wt %, 2-DiMethyl Amino Ethyl Methacrylate (DMAEMA) of 1 wt % have been applied in photo-initiation system for the purpose of initiating matrix resins’ co-polymerization. Wear resistance, flexural strength, hardness and compressive strength were measured. The results indicated an increase in the mechanical properties in the samples containing nano-size filler particles. It is interesting to note that, this improvement was observed at much lower nano-size filler content. Physicochemical properties, such as Solubility (SL), Water Sorption (WS) as well as the Volumetric Shrinkage (VS) have been examined. FT-IR as well as SEM have been utilized for implementing the characterization. SEM has been applied for showing particle size distribution as well as the particle agglomeration that is related to the treated nano-fillers in nano-composites. FT-IT is initially applied for identifying qualitative compositions regarding the nano-composites’ compositions. The Thermal stability of all dental nano-ocomposites was also studied using TGA and DSC techniques.

Synthesis and characterization of novel nanocomposites with nanofillers particles and their applications as dental materials

Using copolymers materials in the preparation of dental fillings is now more common as a result for needs for more esthetic materials of filling and the international ban on the use of products that contain mercury, amongst others dental amalgams. On the other hand, a disadvantage with the Dental Nanocomposites is that they have a polymerization shrinkage. Particles of the filler are combined in the amongst other components for shrinkage minimization. Filler particle sizes have decreased lately and the majority of Dental Nanocomposites include Nano-particles. New Nanocomposites materials based on 2,2 propyl bisphenyl glycidyldimethacrylate (Bis-GMA) and unsaturated monomers ( Methacrylic acid,Acrylicacid,2,2propylbisphenylglycidyldimethacrylate,Triethyleneglycoldimethacrylate ) with Nano inorganic fillers such as (SiO2,ZrO2 and Hydroxyapatite) were characterized and synthesized for the sake of evaluating the potential applications they have in the field of dentistry, as restoration materials. The initial method was generating and characterizing new dental Nano-composites in presence of Triethylene glycol dimethacrylate (TEGDMA) as crosslinking agent. Composites which contain Bis-GMA and Triethylen glycoldimethacrylate) at the ratio (wt/wt) of 40/20, filled with various Nanofiller amounts (about 4.6%wt) were produced. Photo-polymerization has been induced with camphoroquinone / N,N-dimethylaminoethyl methacrylate(CQ/DMAEMA) present, as a system of photo-initiation. Physicochemical properties, such as volumetric shrinkage (VS), water sorption (WS) and water solubility (WSL) were studied. Characterization is performed with the use of SEM and FTIR spectrum. SEM is utilized for showing the distributions of particle sizes and particle agglomeration of the treated Nanofillers in Nanocomposite. FTIR spectroscopy is initially utilized for identifying qualitative construction of the Nanocomposites. The Thermal stability of all dental Nanocomposites were also studied using the TGA and DSC techniques. The strength and the aesthetic characteristics of resin based Nanocomposite open the possibility of using it for each of the posterior and anterior restorations. Flexural strength, compressive strength, wear resistance and hardness were evaluated. The presented research has the aim of addressing current key utilizations of the practical Nanotechnology in the field of dentistry, most importantly, tooth structure restoration with Resin-based composites (RBCs) which benefit from the Nano-particles.

Mechanistic, genomic and proteomic study on the effects of BisGMA-derived biodegradation product on cariogenic bacteria

ObjectivesInvestigate the effects of a Bis-phenyl-glycidyl-dimethacrylate (BisGMA) biodegradation product, bishydroxypropoxyphenyl-propane (BisHPPP), on gene expression and protein synthesis of cariogenic bacteria. MethodsQuantitative real-time polymerase chain reaction was used to investigate the effects of BisHPPP on the expression of specific virulence-associated genes, i.e. gtfB, gtfC, gbpB, comC, comD, comE and atpH in Streptococcus mutans UA159. Possible mechanisms for bacterial response to BisHPPP were explored using gene knock-out and associated complemented strains of the signal peptide encoding gene, comC. The effects of BisHPPP on global gene and protein expression was analyzed using microarray and quantitative proteomics. The role of BisHPPP in glucosyltransferase (GTF) enzyme activity of S. mutans biofilms was also measured. ResultsBisHPPP (0.01, 0.1mM) up-regulated gtfB/C, gbpB, comCDE, and atpH most pronounced in biofilms at cariogenic pH (5.5). The effects of BisHPPP on the constructed knock-out and complemented strains of comC from quorum-sensing system, implicated this signaling pathway in up-regulation of the virulence-associated genes. Microarray and proteomics identified BisHPPP-regulated genes and proteins involved in biofilm formation, carbohydrate transport, acid tolerance and stress-response. GTF activity was higher in BisHPPP-exposed biofilms when compared to no-BisHPPP conditions. SignificanceThese findings provide insight into the genetic and physiological pathways and mechanisms that help explain S. mutans adaptation to restorative conditions that are conducive to increased secondary caries around resin composite restorations and may provide guidance to clinicians’ decision on the selection of dental materials when considering the long term oral health of patients and the interactions of composite resins with oral bacteria.

Physical and chemical properties of an antimicrobial Bis-GMA free dental resin with quaternary ammonium dimethacrylate monomer

The objective of this study was to evaluate the antibacterial activity, physicochemical properties of the quaternary ammonium dimethacrylate monomer N,N-bis[2-(3-(methacryloyloxy)propanamido)-ethyl]-N-methylhexadecyl ammonium bromide (IMQ-16) containing diurethane dimethacrylate (UDMA)/tricyclodecane dimethanol diacrylate (SR833s) resin system and compare with bisphenylglycidyl dimethacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) resin system. It was hypothesized that the physical and chemical properties of the experimental polymers would be comparable with Bis-GMA/TEGDMA polymer and IMQ-16 monomer could endow the UDMA/SR833s resin with antibacterial activity. Double bond conversion (DC) was measured using Fourier transform infrared spectroscopy (FTIR). Mechanical properties including flexural strength (FS) and flexural modulus (FM) were measured by three-point bending test with bars of 2mm×2mm×25mm. Water sorption (WS) and solubility (WSL) were also investigated. Antibacterial activity of obtained polymers against Streptococcus mutans Ingbitt (S. mutans) was tested through direct contact test (DCT). The presence of antibacterial activity due to soluble components was also investigated by agar diffusion test (ADT). All of the polymers containing IMQ-16 exhibited improvements in WS and WSL, while maintaining equivalent DC and FS relative to the Bis-GMA/TEGDMA control system. Incorporation of 17% and 20% of IMQ-16 into UDMA/SR833s resin reduced the viable counts of S. mutans after incubation on the surface of the materials and produced no inhibition zones around the cured discs in ADT. UDMA/SR833s resin system is promising to formulate an antibacterial polymer with equivalent or even higher physicochemical properties relative to Bis-GMA/TEGDMA formulation. IMQ-16 is capable to endow UDMA/SR833s resin system with significant antibacterial activity when the mass ratio is 17% or 20%.

THERMOANALYTICAL STUDY OF MONOMERS: BisGMA, BisEMA, TEGDMA, UDMA

Thermal behavior of BisGMA (bisphenylglycidyl dimethacrylate), TEGDMA (triethylene glycol dimethacrylate), BisEMA (ethoxylated bisphenol-A dimethacrylate), UDMA (Urethane dimethacrylate) monomers and one their mixtures was investigated by TG-DTA, DSC and coupled TG-FTIR. TG-DTA curves of monomers showed that the isolated compounds starts decomposition between 178-297oC and mixture of fotocured monomers starts decomposition at 250oC. The TG-FTIR was used to characterize volatiles released during the thermal cure before thermal decomposition. The DSC curves showed the glass transition, melting point and crystallization temperatures of the samples.

Characterization of porous glass fiber-reinforced composite (FRC) implant structures: porosity and mechanical properties

The aim of this study was to characterize the microstructure and mechanical properties of porous fiber-reinforced composites (FRC). Implants made of the FRC structures are intended for cranial applications. The FRC specimens were prepared by impregnating E-glass fiber sheet with non-resorbable bifunctional bis-phenyl glycidyl dimethacrylate and triethylene glycol dimethacrylate resin matrix. Four groups of porous FRC specimens were prepared with a different amount of resin matrix. Control group contained specimens of fibers, which were bound together with sizing only. Microstructure of the specimens was analyzed using a micro computed tomography (micro-CT) based method. Mechanical properties of the specimens were measured with a tensile test. The amount of resin matrix in the specimens had an effect on the microstructure. Total porosity was 59.5 % (median) in the group with the lowest resin content and 11.2 % (median) in the group with the highest resin content. In control group, total porosity was 94.2 % (median). Correlations with resin content were obtained for all micro-CT based parameters except TbPf. The tensile strength of the composites was 21.3 MPa (median) in the group with the highest resin content and 43.4 MPa (median) in the group with the highest resin content. The tensile strength in control group was 18.9 MPa (median). There were strong correlations between the tensile strength of the specimens and most of the micro-CT based parameters. This experiment suggests that porous FRC structures may have the potential for use in implants for cranial bone reconstructions, provided further relevant in vitro and in vivo tests are performed.

Stress relaxation of trithiocarbonate-dimethacrylate-based dental composites

ObjectivesTo reduce polymerization-induced shrinkage stress while maintaining mechanical properties, reversible addition-fragmentation chain transfer (RAFT)-capable functional groups were incorporated into a photopolymerizable dimethacrylate-based dental composite. We hypothesize that the incorporation of trithiocarbonate-based RAFT functional groups into conventional dimethacrylate dental resins will reduce polymerization stress. MethodsA trithiocarbonate dimethacrylate (TTCDMA) monomer, capable of undergoing radical-mediated RAFT, is mixed with 70wt% BisGMA (bisphenylglycidyl dimethacrylate) and compared to a conventional dental resin comprised of TEGDMA (triethylene glycol dimethacrylate) and 70wt% BisGMA. The shrinkage stress and methacrylate conversion were simultaneously measured during polymerization. The fracture toughness and elastic modulus were measured to evaluate the effect of the TTCDMA monomer on the mechanical properties. All the materials used herein were evaluated as a composite, including 75wt% silica fillers. ANOVA (CI 95%) was conducted to assess the differences between the means. ResultsThe TTCDMA composite exhibited a 65% stress reduction compared with TEGDMA–BisGMA though the reaction rate was slower than the conventional dental composite, owing to the additional RAFT reaction. The fracture toughness and elastic modulus of the TTCDMA-based composite were not significantly different than in the TEGDMA-based composite, while the Tg was decreased by 30°C to 155±2°C. SignificanceDespite only replacing the reactive-diluent, significant and dramatic stress reduction was observed while maintaining the elastic modulus and fracture toughness. This new RAFT-capable monomer shows great promise to replace the reactive diluent in BisGMA-based dental materials. Formulation optimization and further exploration of other RAFT-capable functional groups will provide further stress reduction in dental materials.

Contraction stress related to composite inorganic content

Objectives The role of inorganic content on physical properties of resin composites is well known. However, its influence on polymerization stress development has not been established. The aim of this investigation was to evaluate the influence of inorganic fraction on polymerization stress and its determinants, namely, volumetric shrinkage, elastic modulus and degree of conversion. Methods Eight experimental composites containing 1:1 BisGMA (bisphenylglycidyl dimethacrylate):TEGDMA (triethylene glycol dimethacrylate) (in mol) and barium glass at increasing concentrations from 25 to 60 vol.% (5% increments) were tested. Stress was determined in a universal test machine using acrylic as bonding substrate. Nominal polymerization stress was obtained diving the maximum load by the cross-surface area. Shrinkage was measured using a water picnometer. Elastic modulus was obtained by three-point flexural test. Degree of conversion was determined by FT-Raman spectroscopy. Results Polymerization stress and shrinkage showed inverse relationships with filler content ( R 2 = 0.965 and R 2 = 0.966, respectively). Elastic modulus presented a direct correlation with inorganic content ( R 2 = 0.984). Degree of conversion did not vary significantly. Polymerization stress showed a strong direct correlation with shrinkage ( R 2 = 0.982) and inverse with elastic modulus ( R 2 = 0.966). Significance High inorganic contents were associated with low polymerization stress values, which can be explained by the reduced volumetric shrinkage presented by heavily filled composites.

Influence of BisGMA, TEGDMA, and BisEMA contents on viscosity, conversion, and flexural strength of experimental resins and composites

Different monomer structures lead to different physical and mechanical properties for both the monomers and the polymers. The objective of this study was to determine the influence of the bisphenylglycidyl dimethacrylate (BisGMA) concentration (33, 50 or 66 mol%) and the co-monomer content [triethylene glycol dimethacrylate (TEGDMA), ethoxylated bisphenol-A dimethacrylate (BisEMA), or both in equal parts] on viscosity (eta), degree of conversion (DC), and flexural strength (FS). Eta was measured using a viscometer, DC was obtained by Fourier transfer Raman (FT-Raman) spectroscopy, and FS was determined by three-point bending. At 50 and 66% BisGMA, increases in eta were observed following the partial and total substitution of TEGDMA by BisEMA. For 33% BisGMA, eta increased significantly only when no TEGDMA was present. The DC was influenced by BisGMA content and co-monomer type. Mixtures containing 66% BisGMA showed a lower DC compared with mixtures containing other concentrations of BisGMA. The BisEMA mixtures had a lower DC compared with the TEGDMA mixtures. The FS was influenced by co-monomer content only. BisEMA mixtures presented a statistically lower FS, followed by TEGDMA + BisEMA mixtures, and then by TEGDMA mixtures. Partial or total replacement of TEGDMA by BisEMA increased eta, which was associated with the observed decreases in DC and FS. Although the BisGMA content influenced the DC, it did not affect the FS results.

Contraction Stress Determinants in Dimethacrylate Composites

The influence of composite organic content on polymerization stress development remains unclear. It was hypothesized that stress was directly related to differences in degree of conversion, volumetric shrinkage, elastic modulus, and maximum rate of polymerization encountered in composites containing different BisGMA (bisphenylglycidyl dimethacrylate) concentrations and TEGDMA (triethylene glycol dimethacrylate) and/or BisEMA (ethoxylated bisphenol-A dimethacrylate) as co-monomers. Stress was determined in a tensilometer. Volumetric shrinkage was measured with a mercury dilatometer. Elastic modulus was obtained by flexural test. We used fragments of flexural specimens to determine degree of conversion by FT-Raman spectroscopy. Reaction rate was determined by differential scanning calorimetry. Composites with lower BisGMA content and those containing TEGDMA showed higher stress, conversion, shrinkage, and elastic modulus. Polymerization rate did not vary significantly, except for the lower value of the 66% TEGDMA composite. We used linear regressions to evaluate the association between polymerization stress and conversion (R(2)=0.905), shrinkage (R(2)=0.825), and modulus (R(2)=0.623).

Residual monomers and degree of conversion of partially bioresorbable fiber-reinforced composite

The aim of this study was to evaluate the total quantity of residual monomer (bis-phenyl glycidyl dimethacrylate, i.e. Bis-GMA, and triethylene glycol dimethacrylate, i.e. TEGDMA), residual monomer release into water and the degree of monomer conversion (DC%) of glass fiber-reinforced composites (FRC) with a partially bioresorbable polymer matrix. Another aim was to find out whether the curing mode affects the quantity of residual monomer and degree of conversion. Glass fibers were preimpregnated with a bioresorbable poly(hydroxyproline) amide and non-resorbable Bis-GMA–TEGDMA resin system. Specimens were immersed in water for 1, 3 or 7 days (37 °C) to determine the quantity of leached residual monomers, or in the solvent tetrahydrofuran for 3 days to determine the total quantity of residual monomers by high performance liquid chromatography. DC% was measured by Fourier transform infrared spectroscopy. The quantity of residual monomer of the specimens decreased when the specimens contained glass fibers, and/or poly(hydroxyproline) amide, and/or when it was post-cured. The majority of the residual monomers were leached out during the first 24 h of immersion in water. The DC% of the specimens increased when post-cured. Also glass fibers in the composite increased the DC% in contrast to Bis-GMA–TEGDMA resin only. In conclusion, use of poly(hydroxyproline) amide as a sizing of the glass fibers in FRC does not increase the quantity of residual monomers. These results suggest that this new kind of partially bioresorbable FRC has potential for biomedical applications.

Biomimetic mineralization of partially bioresorbable glass fiber reinforced composite

The aim of this study was to investigate the biomimetic mineralization on the surface of a glass fiber reinforced composite with partially resorbable biopolymer matrix. The E-glass fibers were preimpregnated with a novel biopolymer of poly(hydroxyproline) amide, and further impregnated in the monomer system of bis-phenyl glycidyl dimethacrylate (Bis-GMA)--triethylene glycol dimethacrylate (TEGDMA), which formed interpenetrating polymer networks (IPN) with the preimpregnation polymer. After light-initiated polymerization of the monomer system, the rhombic test specimens (n = 6) were immersed in the simulated body fluid (SBF) with the bioactive glass for 24 h, and then the apatite nuclei were allowed to grow for 1, 3, 5 and 7 days in the SBF. The control test specimens (n = 3) were immersed in SBF without the bioactive glass. According to the scanning electron microscope (SEM), a mineral layer was formed on the surface of all the specimens, which were immersed with bioactive glass. The layer was thickened by the prolonged immersion time to a uniform layer. The Ca/P atomic ratio of the mineral varied between 1.30 and 1.54 as analyzed by the energy dispersive X-ray analysis (EDXA). The Fourier transform infrared spectroscopy (FT-IR) spectra gave signals for the mineral, which are characteristic of both bone-like apatite and orthocalciumphosphate. In conclusion, the mineral layer was formed on the surfaces of the specimens by biomimetic mineralization, the mineral being a mixture of bone-like apatite, orthocalciumphosphate and other calcium phosphates.

Commercial Dental Composite: Determination of Reaction Advancement and Study of the Migration of Organic Compounds

This work on organic dental composites was undertaken to determine the role of residual reactive methacrylate functions at the end of the photopolymerization cycle, and to investigate the fate of the residual monomers and oligomers in organic (ethanol) and aqueous (water and artificial saliva) media. The results show that all the methacrylate monomers present in dentine migrate into ethanol (about 1% (w/w)). In aqueous media on the other hand, only the most hydrophilic monomer (UDMA) migrates (0.05% (w/w)) into water and 0.03% into artificial saliva (pH = 9). This desorption in the three media is accompanied by the hydrolysis of monomers, leading to the formation of monohydrolyzed urethane dimethacrylate (UDMA) and bis-phenyl glycidyl dimethacrylate (BISGMA); UDMA and BISGMA are completely hydrolyzed in artificial saliva. The alkalinity of the milieu apparently favours the hydrolysis of methacrylate functions.

Identifying enzyme activities within human saliva which are relevant to dental resin composite biodegradation

Esterase activities similar to those of cholesterol and pseudocholine esterases (CE and PCE, respectively) have been detected within whole human saliva. Since commercial CE has been shown to possess distinct activity relative to PCE for select components in dental composites, it is hypothesized that esterases isolated from human saliva will also show selectivity towards specific monomer elements within the composites. The objective of this work was to carry out the isolation of these activities from whole human saliva and study their individual effects on resin monomers such as Bis-phenyl glycidyl dimethacrylate (aromatic structure) and triethylene glycol dimethacrylate (hydrophilic structure), and on cured composites containing the latter monomers. Human saliva samples were processed, fractionated on a gel filtration column and assayed for CE and PCE-like activity. Selected fractions were incubated at 37 °C with the above monomers and select commercial composites. Degradation was monitored using high-performance liquid chromatography. The fraction with the highest cholesterol esterase-like character preferentially degraded the aromatic monomer and significantly degraded more of the composite's material relative to a fraction containing low amounts of the cholesterol esterase activity but elevated pseudocholine esterase-like activity. Hence, it was concluded that select salivary esterases had preferences for distinct composite resin components.

The influence of resin chemistry on a dental composite's biodegradation.

Previous work reported that commercial dental composite resins containing a urethane-modified bisGMA (bisphenylglycidyl dimethacrylate)/TEGDMA (triethylene glycol dimethacrylate) (ubis) based monomer system showed a 10-fold reduction in the release of a bisGMA-derived product, bishydroxypropoxyphenyl propane (bisHPPP), as compared with that found for bisGMA/TEGDMA (bis) based composites after incubation with cholesterol esterase (CE). Unfortunately, these materials also differed substantially in filler type and content, making it impossible to directly relate any specific parameter to the differences in biodegradation levels. By controlling for filler content and type, the current study will seek to probe the biomolecular interactions between composite resin chemistry and esterase activity in order to help explain the observed differences in biodegradation levels between the ubis and bis resin systems. After 32 days of incubation, buffer and CE solutions were analyzed for degradation products using high-performance liquid chromatography, UV spectroscopy, and mass spectrometry. Both materials were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. In the CE groups, the ubis system showed a 2.6- to 86-fold reduction (dependent on the product) in the amount of isolated products relative to the bis system (p < 0.01). Scanning electron microscopy data also demonstrated the relative stability of the ubis system and X-ray photoelectron spectroscopy analysis showed a higher content of the ester bond at the surface of the bis samples. Fourier transform infrared data showed that both resins had similar conversions. Because both systems were identical except for their monomer systems, it was concluded that changes in biostability were associated with chemistry. Crosslinking, hydrophobicity, and solubility all relate to ubis's pro-stability.

Salivary esterase activity and its association with the biodegradation of dental composites.

Pseudocholinesterase (PCE) and cholesterol esterase (CE) can hydrolyze bisphenylglycidyl dimethacrylate (bisGMA) and triethylene glycol dimethacrylate (TEGDMA) monomers. This study will test the hypothesis that enzyme activities showing CE and PCE character are found in human saliva at levels sufficient to hydrolyze ester-containing composites important to restorative denstistry. The study also seeks to ask if the active sites of CE and PCE with respect to composite could be inhibited. Photo-polymerized model composite resin was incubated in PCE and CE solutions, in the presence and absence of a specific esterase inhibitor, phenylmethylsulfonyl fluoride (PMSF). Incubation solutions were analyzed for resin degradation products by high-performance liquid chromatography (HPLC), UV spectroscopy, and mass spectrometry. Saliva was found to contain both hydrolase activities at levels that could degrade composite resins. PMSF inhibited the composite degradation, indicating a material hydrolysis mechanism similar to the enzymes' common function.

Interactions between resin monomers and commercial composite resins with human saliva derived esterases

Cholesterol esterase (CE) and pseudocholinesterase (PCE) have been reported to degrade commercial and model composite resins containing bisphenylglycidyl dimethacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA) or the latter in combination with urethane modified BisGMA monomer systems. In addition, human saliva has been shown to contain esterase like activities similar to CE and PCE. Hence, it was the aim of the current study to determine to what extent human saliva could degrade two common commercial composite resins (Z250 from 3M Inc. and Spectrum TPH from L.D. Caulk) which contain the above monomer systems. Saliva samples from different volunteers were collected, processed, pooled, and freeze-dried. TEGDMA and BisGMA monomers were incubated with human saliva derived esterase activity (HSDEA) and their respective hydrolysis was monitored using high performance liquid chromatography (HPLC). Both monomers were completely hydrolyzed within 25 h by HSDEA. Photopolymerized composites were incubated with buffer or human saliva (pH 7.0 and 37°C) for 2, 8 and 16 days. The incubation solutions were analyzed using HPLC and mass spectrometry. Surface morphology characterization was carried out using scanning electron microscopy. Upon biodegradation, the Z250 composite yielded higher amounts of BisGMA and TEGDMA related products relative to the TPH composite. However, there were higher amounts of ethoxylated bis-phenol A released from the TPH material. In terms of total mass of products released, human saliva demonstrated a greater ability to degrade Z250. In summary, HSDEA has been shown to contain esterase activities that can readily catalyze the biodegradation of current commercial composite resins.