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Nigerian Journal of Clinical Practice Jan 2024Compomers are restorative materials commonly used in pediatric dentistry. It is important to investigate the monomer release of materials used especially in pediatric...
BACKGROUND
Compomers are restorative materials commonly used in pediatric dentistry. It is important to investigate the monomer release of materials used especially in pediatric patients. The aim of this study was to evaluate the residual monomer released from different-colored flowable compomers at five polymerization times.
MATERIALS AND METHODS
Three experimental groups were formed: Group 1: pink flowable compomer (Twinky Star, VOCO, Germany), Group 2: blue flowable compomer (Twinky Star, VOCO), Group 3: white flowable compomer, A2 color of Dyract XP (Dentslpy DeTrey, Konstanz, Germany). For each group, samples were prepared using standard cylindrical Teflon molds (n = 10), and the compomers were cured using a light-emitting diode (LED) source in accordance with the manufacturer's recommendations. During each time period, the number of residual monomers: bisphenol-A glycidyl methacrylate (bis-GMA), urethane dimethacrylate (UDMA), hydroxyethyl methacrylate (HEMA), and triethylene glycol dimethacrylate (TEGDMA) were determined with high-performance liquid chromatography (HPLC). All data were analyzed statistically.
RESULTS
In all groups, the amount of residual monomers increased after 1-h release periods (P < 0.05). For 2 weeks, the total residual monomers released were determined at most in Group 3 and at least in Group 1. However, there was no significant difference between the groups in terms of released amounts of monomers (P > 0.05).
CONCLUSIONS
According to the study, when the total amount of residual monomer released from all groups was compared, no difference was found and it was observed that none of them exceeded the toxic dose. Flowable colored compomers can be used as safely as white compomers in pediatric dentistry.
Topics: Humans; Child; Compomers; Polymerization; Bisphenol A-Glycidyl Methacrylate; Chromatography, High Pressure Liquid; Materials Testing; Composite Resins
PubMed: 38317028
DOI: 10.4103/njcp.njcp_1995_21 -
Marine Pollution Bulletin May 2022Plastic debris degrades in the water environments due to various factors such as mechanical stress. Small-sized degradation products, including plastic monomers, are...
Plastic debris degrades in the water environments due to various factors such as mechanical stress. Small-sized degradation products, including plastic monomers, are currently monitored using equipment which might be unsuitable for screening. Here, we developed a recombinant whole-cell bacterial biosensor, which could be used for this type of monitoring. The Escherichia coli pBAV1K-ACU-lucFF cells contain a luciferase-based reporter system under the control of acrylic acid specific promoter. The biosensor cells were used to detect acrylic acid monomers from both sterile water and spiked lake water samples, indicating usability with environmental samples. Furthermore, poly(acrylic acid) was incubated in salt water, and the biosensor cells could identify acrylic acid monomers originating from it. Thus, the cells could be used to observe similar processes in the environment. The results show that the bacterial biosensors could complement the current research methods of plastic monomer monitoring in water environments with a potential for higher throughputs.
Topics: Acrylates; Bacteria; Biosensing Techniques; Escherichia coli; Plastics; Water
PubMed: 35339059
DOI: 10.1016/j.marpolbul.2022.113568 -
Journal of Applied Biomaterials &... Apr 2018Light-activated resin-based dental fissure sealants are the most widely accepted among clinicians. The objective of this study was to determine monomer release of 3...
BACKGROUND
Light-activated resin-based dental fissure sealants are the most widely accepted among clinicians. The objective of this study was to determine monomer release of 3 different light-curing fissure sealants in vitro: Control Seal (Voco, Germany), Fissurit FX (Voco, Germany) and R&D Series Fıssured Nova (Imicrly, Turkey).
METHODS
Each material was polymerized with a curing light: Valo Cordless (Ultradent) LED in standard mode for 20 seconds (n = 27) and 40 seconds (n = 27) and in Xtra power mode (plasma arc) for 3 seconds (n = 27). High-performance liquid chromatography (HPLC) was used to measure the amount of monomers released over 1, 3 and 7 days.
RESULTS
Plasma arc groups showed the highest release of monomers at 1, 3 and 7 days in the 3 fissure sealant groups (p<0.001). The greatest release of bisphenol A glycidyl methacrylate (bis-GMA) determined for R&D Series Fissured Nova both with LED 20 seconds and LED 40 seconds and for Control Seal was with the plasma arc. With time, release of the monomer was reduced for all polymerization systems.
CONCLUSIONS
Efficiency of the polymerization system and applying the recommended curing time for light-activated resin-based dental materials are very important to protect the patient from potential hazards of residual monomers.
Topics: Bisphenol A-Glycidyl Methacrylate; Chromatography, High Pressure Liquid; Dental Fissures; Pit and Fissure Sealants; Plasma Gases
PubMed: 29048706
DOI: 10.5301/jabfm.5000380 -
Molecules (Basel, Switzerland) Sep 2022How to use bioinformatics methods to quickly and accurately locate the effective targets of traditional Chinese medicine monomer (TCM) is still an urgent problem needing...
How to use bioinformatics methods to quickly and accurately locate the effective targets of traditional Chinese medicine monomer (TCM) is still an urgent problem needing to be solved. Here, we used high-throughput sequencing to identify the genes that were up-regulated after cells were treated with TCM monomers and used bioinformatics methods to analyze which transcription factors activated these genes. Then, the binding proteins of these transcription factors were analyzed and cross-analyzed with the docking proteins predicted by small molecule reverse docking software to quickly and accurately determine the monomer's targets. Followeding this method, we predicted that the TCM monomer Daphnoretin (DT) directly binds to JAK2 with a binding energy of -5.43 kcal/mol, and activates the JAK2/STAT3 signaling transduction pathway. Subsequent Western blotting and in vitro binding and kinase experiments further validated our bioinformatics predictions. Our method provides a new approach for quickly and accurately locating the effective targets of TCM monomers, and we also have discovered for the first time that TCM monomer DT is an agonist of JAK2.
Topics: Computational Biology; Drugs, Chinese Herbal; Medicine, Chinese Traditional; Molecular Docking Simulation; Signal Transduction; Transcription Factors
PubMed: 36144838
DOI: 10.3390/molecules27186105 -
Environmental Health Perspectives Oct 1976A simplified mathematical model which made use of Fick's laws of diffusion written in spherical coordinates was developed to describe the rate of diffusion of residual...
A simplified mathematical model which made use of Fick's laws of diffusion written in spherical coordinates was developed to describe the rate of diffusion of residual monomers from polymer resins. The properties of the monomer-polymer system which influenced the amount of monomer remaining in the polymer as a function of time were the diffusivity and solubility of the monomer in the polymer, and the particle size of the polymer resin. This model was used to analyze literature data on the diffusion of residual vinyl chloride monomer in polyvinyl chloride resins made by the suspension process. It was concluded that particle size of the resin was a significant parameter which should be taken advantage of in process equipment designed to remove residual monomer from PVC resins. The diffusivity of the monomer in the polymer was a function of the solubility of the monomer in the polymer. Monomer solubility can be determined from Henry's law. It was suggested that this model could be adapted to describe diffusion of monomers from any monomer-polymer system, and would be a useful approach to modeling the transport of nonreactive chemical additives from plastics.
Topics: Diffusion; Models, Chemical; Particle Size; Polyvinyl Chloride; Resins, Synthetic; Solubility; Temperature; Vinyl Chloride
PubMed: 1026410
DOI: 10.1289/ehp.7617227 -
The Journal of Prosthetic Dentistry Jul 2003Studies have suggested that monomers may be able to permeate dental gloves.
STATEMENT OF PROBLEM
Studies have suggested that monomers may be able to permeate dental gloves.
PURPOSE
This study examined the permeability of disposable dental gloves to 6 kinds of dental monomers.
MATERIAL AND METHODS
The permeability of 6 kinds of dental monomers (methyl methacrylate [MMA], 2-hydroxyethyl methacrylate [HEMA], triethyleneglycol methacrylate [TEGDMA], ethyleneglycol dimethacrylate [EGDMA], urethane dimethacrylate [UDMA], and Bis-glycidyl methacrylate [Bis-GMA]) through 5 kinds of dental gloves (latex, powder-free latex, coated latex, polychloroprene, and polyvinyl chloride) was examined for up to 180 minutes at 37 degrees C. The fingers of unused gloves without pin holes were cut and used in the experiments. Five specimens per test group were examined. One type of monomer was poured into each finger and dipped in ethanol. The ethanol for extraction was measured by a spectrophotometer at a wavelength of 210 nm, and the results were analyzed by analysis of variance and the Kruskal-Wallis test (P<.05).
RESULTS
Four of the monomers tested (MMA, HEMA, TEGDMA, and EGDMA) permeated the gloves tested, whereas 2 (UDMA and Bis-GMA) did not (P>.01). The amount of monomers permeating the latex in 10 minutes was 0.8 +/- 0.6, 0.6 +/- 0.6, 0.07 +/- 0.1, 0.07 +/- 0.1, 0.1 +/- 0.1 and 0.06 +/- 0.1 microL/mL for MMA, HEMA, EGDMA, TEGDMA, UDMA, and Bis-GMA, respectively. The amount of permeated monomer was then increased in relation to the examination time, and in MMA and HEMA, permeation occurred rapidly during the initial 60 minutes at 3 times the 10-minute values, then continued gradually and linearly. The polyvinyl chloride glove showed the greatest monomer permeability. Two-way analysis of variance showed significant correlations between MMA, HEMA, EGDMA or TEGDMA and UDMA or Bis-GMA (P<.01). Statistical significance was shown between polyvinyl chloride and latex, powder-free latex, coated latex or polychloroprene (P<.01). However, there was no significant relation between any kind of dental monomer and any kind of dental glove.
CONCLUSION
Within the limitations of this study, 4 of the monomers tested permeated all of the gloves tested.
Topics: Analysis of Variance; Bisphenol A-Glycidyl Methacrylate; Composite Resins; Disposable Equipment; Ethanol; Gloves, Surgical; Humans; Latex; Materials Testing; Methacrylates; Methylmethacrylate; Neoprene; Permeability; Polyethylene Glycols; Polymethacrylic Acids; Polyurethanes; Polyvinyl Chloride; Solvents; Spectrophotometry, Ultraviolet; Statistics, Nonparametric; Temperature; Time Factors
PubMed: 12869975
DOI: 10.1016/s0022-3913(03)00178-1 -
Journal of Materials Science. Materials... May 2023The aim of this work was to investigate the elution of residual monomers as a function of the manufacturing process, which are CAD/CAM manufacturing, self-curing and 3D...
The aim of this work was to investigate the elution of residual monomers as a function of the manufacturing process, which are CAD/CAM manufacturing, self-curing and 3D printing. The experimental materials used consisted of the base monomers TEGDMA, Bis-GMA and Bis-EMA and 50 wt.% fillers. Additionally, a 3D printing resin without fillers was tested. The elution of the base monomers into the different media (water, ethanol and ethanol/water (75/25 vol. %)) at 37 °C over a period of up to 120 d as well as the degree of conversion (DC) by FTIR were investigated. No monomer elution could be detected in water. Most residual monomers in both other media were released from the self-curing material whereas the 3D printing composite released relatively little. The CAD/CAM blanks released hardly any quantitatively detectable amounts of monomers. Relative to the base composition, TEGDMA eluted less than Bis-GMA and Bis-EMA. DC did not correlate with residual monomer release; thus, leaching was determined not only by the amount of residual monomers present but by further factors as possibly network density and structure. The CAD/CAM blanks and the 3D printing composite showed similar high DC but lower residual monomer release from the CAD/CAM blank, likewise the self-curing composite and the 3D printing resin exhibited similar DC but different monomer elution. In terms of residual monomer elution and DC, the 3D printing composite seems promising as a new material class for the use as temporary dental crowns and bridges.
Topics: Bisphenol A-Glycidyl Methacrylate; Composite Resins; Materials Testing; Water; Printing, Three-Dimensional; Ethanol; Crowns; Dental Materials
PubMed: 37173418
DOI: 10.1007/s10856-023-06729-z -
Journal of Leukocyte Biology Feb 2012Chemokines exert their function by binding the GPCR class of receptors on leukocytes and cell surface GAGs in target tissues. Most chemokines reversibly exist as... (Comparative Study)
Comparative Study
Chemokines exert their function by binding the GPCR class of receptors on leukocytes and cell surface GAGs in target tissues. Most chemokines reversibly exist as monomers and dimers, but very little is known regarding the molecular mechanisms by which the monomer-dimer equilibrium modulates in vivo function. For the chemokine CXCL8, we recently showed in a mouse lung model that monomers and dimers are active and that the monomer-dimer equilibrium of the WT plays a crucial role in regulating neutrophil recruitment. In this study, we show that monomers and dimers are also active in the mouse peritoneum but that the role of monomer-dimer equilibrium is distinctly different between these tissues and that mutations in GAG-binding residues render CXCL8 less active in the peritoneum but more active in the lung. We propose that tissue-specific differences in chemokine gradient formation, resulting from tissue-specific differences in GAG interactions, are responsible for the observed differences in neutrophil recruitment. Our observation of differential roles played by the CXCL8 monomer-dimer equilibrium and GAG interactions in different tissues is novel and reveals an additional level of complexity of how chemokine dimerization regulates in vivo recruitment.
Topics: Amino Acid Substitution; Animals; Chemotaxis, Leukocyte; Dimerization; Female; Glycosaminoglycans; Humans; Interleukin-8; Lung; Mice; Mice, Inbred BALB C; Models, Molecular; Mutagenesis, Site-Directed; Neutrophils; Organ Specificity; Peritoneum; Protein Binding; Protein Conformation; Recombinant Fusion Proteins; Specific Pathogen-Free Organisms
PubMed: 22140266
DOI: 10.1189/jlb.0511239 -
Journal of the American Chemical Society Aug 2022Transient Cu-H monomers have long been invoked in the mechanisms of substrate insertion in Cu-H catalysis. Their role from Cu-H aggregates has been mostly inferred since...
Isolation of a Cu-H Monomer Enabled by Remote Steric Substitution of a -Heterocyclic Carbene Ligand: Stoichiometric Insertion and Catalytic Hydroboration of Internal Alkenes.
Transient Cu-H monomers have long been invoked in the mechanisms of substrate insertion in Cu-H catalysis. Their role from Cu-H aggregates has been mostly inferred since ligands to stabilize these monomeric intermediates for systematic studies remain limited. Within the last decade, new sterically demanding -heterocyclic carbene (NHC) ligands have led to isolable Cu-H dimers and, in some cases, spectroscopic characterization of Cu-H monomers in solution. We report an NHC ligand, IPr*R, containing R groups of CHPh and CPh on the ligand periphery for the isolation of a Cu-H monomer for insertion of internal alkenes. This reactivity has not been reported for (NHC)CuH complexes despite their common application in Cu-H-catalyzed hydrofunctionalization. Changing from CHPh to CPh impacts the relative concentration of Cu-H monomers, rate of alkene insertion, and reaction of a trisubstituted internal alkene. Specifically, for R = CPh, monomeric (IPr*CPh)CuH was isolated and provided >95% monomer (10 mM in CD). In contrast, for R = CHPh, solutions of [(IPr*CHPh)CuH] are 80% dimer and 20% (IPr*CHPh)CuH monomer at 25 °C based on H, C, and H-C HMBC NMR spectroscopy. Quantitative H NMR kinetic studies on cyclopentene insertion into Cu-H complexes to form the corresponding Cu-cyclopentyl complexes demonstrate a strong dependence on the rate of insertion and concentration of the Cu-H monomer. Only (IPr*CPh)CuH, which has a high monomer concentration, underwent regioselective insertion of a trisubstituted internal alkene, 1-methylcyclopentene, to give (IPr*CPh)Cu(2-methylcyclopentyl), which has been crystallographically characterized. We also demonstrated that (IPr*CPh)CuH catalyzes the hydroboration of cyclopentene and methylcyclopentene with pinacolborane.
PubMed: 35853236
DOI: 10.1021/jacs.2c05376 -
Chembiochem : a European Journal of... Feb 2016The formation of multicomponent and bioactive supramolecular polymers is a promising strategy for the formation of biomaterials that match the dynamic and responsive...
The formation of multicomponent and bioactive supramolecular polymers is a promising strategy for the formation of biomaterials that match the dynamic and responsive nature of biological systems. In order to fully realize the potential of this strategy, knowledge of the location and behavior of bioactive components within the system is crucial. By employing synthetic strategies to create multifunctional monomers, coupled with FRET and STORM techniques, we have investigated the formation and behavior of a bioactive and multicomponent supramolecular polymer. By creating a peptide-dye-monomer conjugate, we were able to measure high degrees of monomer incorporation and to visualize the equal distribution of monomers within the supramolecular polymer. Furthermore, by tracking the movement of monomers, we uncovered small differences in the dynamics of the bioactive monomers.
Topics: Benzamides; Biocompatible Materials; Carbocyanines; Coloring Agents; Fluorescence Resonance Energy Transfer; Oligopeptides; Polyethylene Glycols; Polymers; Water
PubMed: 26603687
DOI: 10.1002/cbic.201500606