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Medical Science Monitor : International... Jul 2018BACKGROUND The aim of this study was to evaluate the elution of BisGMA, UDMA, TEGDMA, and HEMA monomers from flowable bulk fill composite resins with different resin...
BACKGROUND The aim of this study was to evaluate the elution of BisGMA, UDMA, TEGDMA, and HEMA monomers from flowable bulk fill composite resins with different resin matrix compositions, polymerized in 4-mm-thick layers, into 3 elution media. MATERIAL AND METHODS Three bulk-fill (SDR® (SDR), X-tra base (XB) and BEAUTIFIL-Bulk Flowable (BF)) resin-composites were tested. Cylindrical samples were immersed in 100% ethanol, 75% ethanol, and distilled water. The concentrations of the monomers were measured using the HLPC method (Agilent Technologies 1200 Series) after 1 and 24 h, as well as after 3, 7, 14, and 21 days. RESULTS After polymerization of the tested resins, there was elution of the BisGMA, UDMA, TEGDMA, and HEMA monomers from the SDR and BF composites, but none of the tested monomers could be detected eluting from XB. The highest penetrations of the polymerized SDR and BF composites were observed in the 100% ethanol solution. This extraction medium eluted the highest amounts of free monomers. Some eluted monomers were not described in the composites Material Safety Data Sheets. CONCLUSIONS The elution of the residual monomers depended on the resin composition and the materials filler/resin matrix ratio. In composite materials, toxicity assessment should be carried out, and should consider both the material composition as given by the manufacturer, and also the residual monomers that elute from the polymerized material. The elution concentration and time of monomers from composites depended on the solvent used. The highest penetrations of the polymerized SDR and BF composites were observed in the 100% ethanol solution, and this extraction medium eluted the highest amounts of free monomers. The 75% ethanol was a more aggressive medium than water in terms of monomer elution from bulk fill composites.
Topics: Chromatography, High Pressure Liquid; Composite Resins; Dental Materials; Materials Testing; Methylmethacrylate
PubMed: 29980660
DOI: 10.12659/MSM.907390 -
The Journal of Prosthetic Dentistry Nov 2014Polyetheretherketone (PEEK) can be used as a framework material for fixed dental prostheses. However, information about the durable bond to veneering resins is still...
STATEMENT OF PROBLEM
Polyetheretherketone (PEEK) can be used as a framework material for fixed dental prostheses. However, information about the durable bond to veneering resins is still scarce.
PURPOSE
The purpose of this study was to investigate the effect of chemical treatments of PEEK on tensile bond strength (TBS) to veneering resins with special emphasis on surface free energy (SFE) and surface roughness (SR).
MATERIAL AND METHODS
Seven-hundred fifty PEEK specimens were fabricated and divided into the following 3 pretreatment groups (n=250/group): etching with sulfuric acid for 60 seconds, etching with piranha acid for 30 seconds, and an unetched control. After pretreatment, SFE was determined by using contact angle measurements and SR with a profilometer (n=10/group). The topography of pretreated PEEK surfaces was examined with scanning electron microscopy. Remaining specimens (n=240 per group) were conditioned with visio.link or Signum PEEK Bond, or were left untreated as the control group. Half of each group was veneered with Sinfony or VITA VM LC (n=40/group), and TBS was measured after storage in distilled water at 37°C for either 24 hours or 60 days. Data were analyzed by 4-way and 1-way ANOVA followed by the Scheffé post hoc test and chi-square test (α=.05).
RESULTS
PEEK specimens etched with sulfuric acid resulted in higher SFE and SR than specimens without pretreatment or etching with piranha acid. Etching with sulfuric acid or piranha acid led to no general recommendations with respect to TBS. Conditioning with visio.link or Signum PEEK Bond significantly increased the TBS (P<.001). PEEK veneered with Sinfony showed significantly higher TBS values than those veneered with VITA VM LC (P<.001).
CONCLUSIONS
Sufficient TBS for bonding to veneering resin can only be achieved when additional adhesive materials were applied.
Topics: Acid Etching, Dental; Benzophenones; Bisphenol A-Glycidyl Methacrylate; Carbon Compounds, Inorganic; Composite Resins; Dental Bonding; Dental Materials; Dental Polishing; Dental Veneers; Humans; Hydrogen Peroxide; Ketones; Materials Testing; Methylmethacrylate; Microscopy, Electron, Scanning; Polyethylene Glycols; Polymers; Polymethacrylic Acids; Silicon Compounds; Sulfuric Acids; Surface Properties; Surface Tension; Temperature; Tensile Strength; Time Factors; Water; Wettability
PubMed: 24969411
DOI: 10.1016/j.prosdent.2014.05.014 -
Dental Materials Journal Mar 2017The purpose of this study was to investigate the effect of different chemical intra-oral prosthesis cleansers on the surface properties of Parylene-C coated and...
The purpose of this study was to investigate the effect of different chemical intra-oral prosthesis cleansers on the surface properties of Parylene-C coated and non-coated polymethyl methacrylate (PMMA). A total of 120 PMMA samples were prepared. Half of the samples were coated with 10 µm of Parylene-C. Samples were exposed to either air (control) or one of two types of denture cleansers, an alkaline peroxide cleanser (Steradent) or a neutral peroxide cleanser with enzyme (Poligrip). Surface roughness (Ra) and surface free energy (SFE) values were measured and compared between groups. Scanning electron microscopy was used for visual analysis. The samples coated with Parylene exhibited significantly lower mean Ra values compared to the non-coated samples (p<0.001). Immersion in Steradent increased the roughness of non-coated PMMA, but its effect was minimized on the coated surfaces. SFE increased for the samples exposed to air and Poligrip, but decreased for the samples exposed to Steradent.
Topics: Dental Implants; Denture Cleansers; Materials Testing; Polymethyl Methacrylate; Surface Properties
PubMed: 28111391
DOI: 10.4012/dmj.2016-254 -
Clinical Oral Investigations Jun 2017Computer-aided design (CAD)/computer-aided manufacturing (CAM) dentures are assumed to have more favourable material properties than conventionally fabricated dentures,...
OBJECTIVES
Computer-aided design (CAD)/computer-aided manufacturing (CAM) dentures are assumed to have more favourable material properties than conventionally fabricated dentures, among them a lower methacrylate monomer release. The aim of this study was to test this hypothesis.
MATERIALS AND METHODS
CAD/CAM dentures were generated from ten different master casts by using four different CAD/CAM systems. Conventional, heat-polymerised dentures served as control group. Denture weight and volume were measured; the density was calculated, and the denture surface area was assessed digitally. The monomer release after 7 days of water storage was measured by high-performance liquid chromatography.
RESULTS
Whole You Nexteeth and Wieland Digital Dentures had significantly lower mean volume and weight than conventional dentures. Baltic Denture System and Whole You Nexteeth had a significantly increased density. Baltic Denture System had a significantly smaller surface area. None of the CAD/CAM dentures released significantly less monomer than the control group.
CONCLUSIONS
All tested dentures released very low amounts of methacrylate monomer, but not significantly less than conventional dentures. A statistically significant difference might nevertheless exist in comparison to other, less recommendable denture base materials, such as the frequently used autopolymerising resins.
CLINICAL RELEVANCE
CAD/CAM denture fabrication has numerous advantages. It enables the fabrication of dentures with lower resin volume and lower denture weight. Both could increase the patient comfort. Dentures with higher density might exhibit more favourable mechanical properties. The hypothesis that CAD/CAM dentures release less monomer than conventional dentures could, however, not be verified.
Topics: Chromatography, High Pressure Liquid; Computer-Aided Design; Dental Materials; Denture Design; Materials Testing; Methylmethacrylate
PubMed: 27704295
DOI: 10.1007/s00784-016-1961-6 -
International Journal of Molecular... Feb 2023In this work, two compounds belonging to the BODIPY family, and previously investigated for their photosensitizing properties, have been bound to the amino-pendant...
In this work, two compounds belonging to the BODIPY family, and previously investigated for their photosensitizing properties, have been bound to the amino-pendant groups of three random copolymers, with different amounts of methyl methacrylate (MMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) in the backbone. The P(MMA--DMAEMA) copolymers have inherently bactericidal activity, due to the amino groups of DMAEMA and to the quaternized nitrogens bounded to BODIPY. Systems consisting of filter paper discs coated with copolymers conjugated to BODIPY were tested on two model microorganisms, () and (). On solid medium, irradiation with green light induced an antimicrobial effect, visible as a clear inhibition area around the coated disks. The system based on the copolymer with 43% DMAEMA and circa 0.70 wt/wt% of BODIPY was the most efficient in both bacterial species, and a selectivity for the Gram-positive model was observed, independently of the conjugated BODIPY. A residual antimicrobial activity was also observed after dark incubation, attributed to the inherently bactericidal properties of copolymers.
Topics: Escherichia coli; Methylmethacrylate; Staphylococcus aureus; Anti-Infective Agents; Methacrylates; Polymers; Anti-Bacterial Agents; Photochemotherapy; Photosensitizing Agents
PubMed: 36901769
DOI: 10.3390/ijms24054340 -
Journal of the American Chemical Society Jun 2022A new molecular rearrangement, the -Quasi-Favorskii rearrangement, has been developed for the construction of highly substituted aziridines. Electron-deficient -sulfonyl...
A new molecular rearrangement, the -Quasi-Favorskii rearrangement, has been developed for the construction of highly substituted aziridines. Electron-deficient -sulfonyl oximes react readily with α,α-disubstituted acetophenone-derived enolates to furnish highly substituted aziridines this unprecedented domino process. In-depth computational studies reveal an asynchronous yet concerted nitrenoid-type rearrangement pathway.
Topics: Aziridines; Methylmethacrylates; Molecular Structure; Stereoisomerism
PubMed: 35674783
DOI: 10.1021/jacs.2c03805 -
BioMed Research International 2022Polymethyl methacrylate (PMMA) is often used in restorative dentistry for its easy fabrication, aesthetics, and low cost for interim restorations. However, poor...
Polymethyl methacrylate (PMMA) is often used in restorative dentistry for its easy fabrication, aesthetics, and low cost for interim restorations. However, poor mechanical properties to withstand complex masticatory forces are a concern for clinicians. Therefore, this study aimed to modify a commercially available PMMA-based temporary restorative material by adding TiO and ZrO nanoparticles in different percentages as fillers and to investigate its physio-mechanical properties. Different percentages (0, 0.5, 1.5, and 3.0 wt%) of TiO and ZrO nanoparticles were mixed with the pristine PMMA resin (powder to liquid ratio: 1 : 1) and homogenized using high-speed mixer. The composites obtained were analyzed for their flexural strength (F.S.), elastic modulus (E.M.), Vickers hardness (H.V.), surface roughness Ra, morphology and water contact angle (WCA). The mean average was determined with standard deviation (SD) to analyze the results, and a basic comparison test was conducted. The results inferred that adding a small amount (0.5 wt%) of TiO and ZrO nanoparticles (NPs) could significantly enhance the physio-mechanical and morphological characteristics of PMMA interim restorations. EM and surface hardness increased with increasing filler content, with 3.0 wt.% ZrO exhibiting the highest EM (3851.28 MPa), followed by 3.0 wt.% TiO (3632.34 MPa). The WCA was significantly reduced from 91.32 ± 4.21° (control) to 66.30 ± 4.23° for 3.0 wt.% ZrO and 69.88 ± 3.55° for 3.0 wt.% TiO. Therefore, TiO and ZrO NPs could potentially be used as fillers to improve the performance of PMMA and similar interim restorations.
Topics: Materials Testing; Nanoparticles; Polymethyl Methacrylate; Surface Properties; Titanium
PubMed: 36033557
DOI: 10.1155/2022/1743019 -
Dental Materials Journal 2014We evaluated the influence of composition and powder/liquid (P/L) ratio on the setting characteristics and mechanical properties of autopolymerized hard direct denture...
Influence of composition and powder/liquid ratio on setting characteristics and mechanical properties of autopolymerized hard direct denture reline resins based on methyl methacrylate and ethylene glycol dimethacrylate.
We evaluated the influence of composition and powder/liquid (P/L) ratio on the setting characteristics and mechanical properties of autopolymerized hard direct denture reline resins composed of methyl methacrylate (MMA, monomethacrylate) and ethylene glycol dimethacrylate [EGDMA, dimethacrylate (cross-linking agent)], with poly (ethyl methacrylate) used as the powder, and a mixture of MMA and EGDMA containing p-tolyldiethanolamine as the monomer. Setting times were determined using an oscillating rheometer and mechanical properties were based on ISO specifications. Setting time increased exponentially with an increase in the ratio of EGDMA to MMA and decrease in P/L ratio. Materials with a liquid component of approximately 75-85 wt% EGDMA and a higher P/L ratio showed higher ultimate flexural strength and flexural modulus. Our results suggest that setting characteristics are more influenced by the ratio of monomethacrylate and cross-linking agent, whereas mechanical properties are more influenced by P/L ratio.
Topics: Composite Resins; Denture Liners; Materials Testing; Methacrylates; Methylmethacrylate; Polymerization
PubMed: 24988884
DOI: 10.4012/dmj.2014-077 -
The Journal of Histochemistry and... Sep 2009Precise localization of proteins and mRNA in histological sections is necessary for evaluating spatial gene expression patterns. Here we report sensitive detection of...
Precise localization of proteins and mRNA in histological sections is necessary for evaluating spatial gene expression patterns. Here we report sensitive detection of the gene products in fish tissues by immunohistochemistry (IHC) and in situ hybridization (ISH) assays on sections of whole specimens and vertebra embedded in methyl methacrylate (MMA) resin. This plastic resin favors easy preparation of various specimen types and enables preparation of large sections with well-preserved cell morphology. IHC analysis of the muscle regulatory factor MyoD in transverse sections of juvenile cod revealed MyoD-positive cells in the dorsolateral parts of the adaxial muscle. ISH revealed less spatially restricted signals of the bone morphogenic protein bmp4 in muscle and brain. To assess the applicability of ISH on sections of bony tissue, col1a1 and col2a1 expression was investigated in non-decalcified vertebra sections of Atlantic salmon. The former was identified in both chondrocytes and osteoblasts, whereas the latter was mostly evident in chondrocytes. We conclude that MMA resin offers easy preparation of large and problematic tissues and the possibility of carrying out both IHC and ISH analyses using standard protocols.
Topics: Animals; Fish Proteins; Gadus morhua; Immunohistochemistry; In Situ Hybridization; Methylmethacrylate; RNA, Messenger; Salmo salar; Spine; Tissue Embedding
PubMed: 19435715
DOI: 10.1369/jhc.2009.953695 -
Travel Medicine and Infectious Disease 2020
Topics: Betacoronavirus; COVID-19; Coronavirus Infections; Humans; Methylmethacrylates; Middle East Respiratory Syndrome Coronavirus; Pandemics; Pneumonia, Viral; SARS-CoV-2
PubMed: 32044388
DOI: 10.1016/j.tmaid.2020.101577