Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ACRYLATES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources
PubMed2005

HPLC determination of residual monomers released from heat-cured acrylic resins.

HPLC was used to examine the leachability of three non-phthalic and four phthalic post-polymerized residual monomers from three commercially available heat-cured acrylic resins. Specimens of equal dimensions were constructed from each brand of material by following the standardized procedure and were stored under three different conditions, namely, distilled water, artificial saliva, and a binary mixture of ethanol/water. The resulting liquids provided samples for analysis by HPLC. Three different experiments were performed for each brand of acrylic and each storage condition in order to examine the effects of parameters, particularly time and temperature. The results obtained from this study suggest that a wide spectrum of residues diffuse out of the three examined acrylic resin materials. The non-phthalic compounds were leached at high concentrations, whereas all the phthalates examined exhibited different degrees of elusion commensurate with the storage condition, brand of material, and type of experiment. It seems that a significant quantity of non-phthalic and phthalic residues diffuse out of the acrylic resin materials examined. The main component extracted was methyl methacrylate, the level of which seems to be time-dependent and decreases for a period of up to 5 days when resins are stored in distilled water at room temperature.

Journal Article↗
PubMed1988

The effect of vacuum-mixed autopolymerizing acrylic resins on porosity and transverse strength.

Three brands of autopolymerizing acrylic resin were mixed and polymerized three different ways and tested for transverse strength and porosity. The procedures tested were bench-curing at ambient temperatures, vacuuming the mix before bench-curing, and curing in a pressure device. The data indicate that both vacuuming the mix and pressure-curing are successful in reducing porosity and increasing transverse strength. These improved properties would be valuable in the fabrication of provisional restorations and occlusal splints. The following conclusions can be drawn: 1. Use of a pressure device decreases porosity and increases the transverse strength in samples of autopolymerizing acrylic resin. 2. Use of a vacuum device on the mixed acrylic resin works as well as pressure polymerizing. 3. Use of either technique is indicated to improve the quality and longevity of autopolymerizing acrylic resin restorations, orthodontic appliances, and occlusal splints.

Chemical Phenomena↗
PubMed1994

Leaching and cytotoxicity of formaldehyde and methyl methacrylate from acrylic resin denture base materials.

Acrylic resin dentures have the potential to elicit irritation, inflammation, and an allergic response of the oral mucosa. Studies of substances leachable from acrylic resins, their cytotoxicity to cultured cells, and means of reducing their leaching were systematically conducted. Under in vivo and in vitro conditions, formaldehyde and methyl methacrylate were significantly leached into human saliva and saliva-substitute buffer, especially from autopolymerized resins. Both leachable substances showed cytotoxic potentials in the range of their leaching concentrations. Formaldehyde was cytotoxic at lower concentrations than methyl methacrylate. Preleaching in water reduced subsequent leaching of both formaldehyde and methyl methacrylate, and the amount of reduction depended on an increase in the preleaching temperatures. Immersion of acrylic resin dentures in hot water (50 degrees C) before insertion is recommended, especially for autopolymerized resins used either for rebasing or as denture base materials, to minimize the risk of adverse reactions in patients who wear acrylic resin dentures.

Cell Count↗
PubMed1994

In vitro abrasion of two acrylic veneers.

OBJECTIVES: The purpose of this investigation was to compare the degree of abrasion in vitro of two acrylic veneers and dental enamel using a dentifrice with and without fluoride. METHODS: Ten specimens of each of the two acrylics and enamel were embedded in resin, and eventually polished to 1 micron with diamond paste. Specimens were brushed in a brushing machine with 10,000 double strokes using a dentifrice (Solidox, A/S Denofa) with and without fluoride. The abrasion was evaluated by the naked eye, by photographs and measured by means of profilometer. RESULTS: One of the polymer materials (Dentacolor, Kulzer) showed a significantly higher resistance to abrasion than the other (Biodent, DeTrey), irrespective of fluoride treatment. Brushing with or without fluoride revealed no significant difference in degree of abrasion between the two acrylic materials. Dentacolor showed significantly higher abrasion resistance than enamel, whereas Biodent did not. There was no significant difference in the degree of abrasion of enamel using dentifrice with or without fluoride. SIGNIFICANCE: Abrasion of acrylic veneering material differed greatly between brands, but did not seem to be influenced by the fluoride in toothpaste.

Composite Resins↗
PubMed2006

(Meth)acrylate monomer-induced cytotoxicity and intracellular Ca(2+) mobilization in human salivary gland carcinoma cells and human gingival fibroblast cells related to monomer hydrophobicity.

To elucidate a possible link between the cytotoxicity and Ca(2+) mobilization by (meth)acrylates, we investigated the cell survival of and change in [Ca(2+)](i) in human salivary gland (HSG) cells (salivary gland carcinoma cell line) and human gingival fibroblasts (HGF) cells treated separately with 9 (meth)acrylate monomers used in dentistry. The cell survival was determined by the MTT method, and the [Ca(2+)](i) changes after the stimulation with the (meth)acrylate monomers were measured in floating indo-1/AM-loaded cells in Ca(2+)-free medium. For both HSG and HGF cells, the cytotoxicity of the monomers was approximately proportional to their hydrophobicity (logP). No increase in [Ca(2+)](i) was found with hydrophilic monomers, even with 10mm stimulation. [Ca(2+)](i) elevation by hydrophobic monomers occurred in a dose- and hydrophobic-dependent manner. The [Ca(2+)](i) change in HSG cells appeared as twin peaks, i.e., an initial sharp peak followed by a delayed broad one; whereas with the HGF cells only a single broad peak was seen, possibly dependent on their membrane quality. Pretreatment with n-butanol or methylmethacrylate enhanced the butylmethacrylate-induced [Ca(2+)](i) elevation, suggesting the [Ca(2+)](i) elevation by (meth)acrylate may be related to monomer hydrophobicity and cell type. The causal link between the cytotoxicity and [Ca(2+)](i) mobilization of monomers is discussed.

Butanols↗
PubMed2005

Effects of surface properties of colloidal silica particles on redispersibility and properties of acrylic-based polyurethane/silica composites.

Nanosilica particles with different surface properties were designed and prepared using colloidal silica particles and four different qualitative silane coupling agents (SCA), namely methyltriethoxysilane (MTES), octyltriethoxysilane (OTES), vinyltriethoxysilane (VTES) and methacryloxypropyltrimethoxysilane (MATMS), and further applied in acrylic resins and corresponding polyurethane coats by in situ polymerization. It was found that different qualitative SCA molecules had very different impacts on the redispersibility of nanosilica particles, the adsorbed acrylic polyol molecules, the viscosities of acrylic polyol/silica hybrid resins, and the properties of acrylic-based polyurethane/silica composites.

Journal Article↗
PubMed1997

Management of condensation on a foldable acrylic intraocular lens after vitrectomy and fluid-air exchange.

PURPOSE: To describe the management of condensation on the posterior surface of a foldable acrylic intraocular lens during vitrectomy and fluid-air exchange. METHODS: A 70-year-old pseudophakic man with a foldable acrylic intraocular lens and open posterior capsule underwent vitrectomy and fluid-air exchange for repair of rhegmatogenous retinal detachment. RESULTS: During pars plana vitrectomy and fluid-air exchange, condensation immediately formed on the posterior surface of the foldable acrylic intraocular lens. This condensation, which prevented a view of the retina, was eliminated by wiping the posterior surface of the intraocular lens with a soft-tipped cannula. CONCLUSION: Although condensation may rapidly form on acrylic intraocular lenses during vitrectomy and fluid-air exchange, it can be managed readily by wiping with a soft-tipped cannula.

Aged↗
PubMed1998

Adhesion of oral Candida albicans isolates to denture acrylic following limited exposure to antifungal agents.

Candidal adherence to denture acrylic surfaces is implicated as the first step in the pathogenesis of Candida-associated denture stomatitis, the most prevalent form of oral candidosis in the West. This condition is treated by topically administered antifungal agents, mainly belonging to the polyenes and azoles. As the intraoral concentrations of antifungals fluctuate considerably due to the dynamics of the oral environment, the effect of short exposure to sublethal concentrations of antifungals on the adhesion of Candida albicans to denture acrylic surfaces was investigated. Seven oral C. albicans isolates were exposed to four-eight times minimum inhibitory concentrations (MIC) of five antifungal drugs, nystatin, amphotericin B, 5-fluorocytosine, ketoconazole and fluconazole, for 1 h. After removing the drug (by repeated washing) the adhesion of these isolates to acrylic strips was assessed by an in vitro adhesion assay. Exposure to antifungal agents significantly reduced the adherence of all seven C. albicans isolates to denture acrylic. The mean percentage reductions of adhesion after limited exposure to nystatin, amphotericin B, 5-fluorocytosine, ketoconazole and fluconazole were 86.48, 90.85, 66.72, 65.88 and 47.42%, respectively. These findings indicate that subtherapeutic doses of antifungals may modulate oral candidal colonization. Further, these results may have an important bearing on dosage regimens currently employed in treating oral candidosis.

Adhesiveness↗
PubMed2003

Single-piece acrylic intraocular lens implantation in children.

PURPOSE: To assess the short-term outcomes of single-piece acrylic intraocular lens (IOL) implantation in children by determining the incidence of postoperative visual axis opacification and the need for a second procedure to clear the axis, cell deposits on the IOL optic, posterior synechias, and IOL decentration. SETTING: Miles Center for Pediatric Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: This retrospective case review comprised 43 consecutive implantations (33 patients) of a single-piece hydrophobic acrylic IOL (AcrySof SA30AL or SA60AT, Alcon). An analysis of 42 eyes with posterior capsulectomy and vitrectomy was performed. Eyes with traumatic cataract and secondary IOLs were excluded. RESULTS: Single-piece acrylic IOLs were implanted in 42 eyes. The mean age was 33.5 months +/- 28.9 (SD) (range 0.5 to 110 months) and the mean follow-up, 12.0 +/- 8.2 months (range 1.0 to 27.5 months). Postoperative opacification of the visual axis occurred in 7 eyes (16.7%). Secondary surgical procedures were required in 5 eyes (11.9%). Lens deposits were observed in 8 eyes (19.0%) and synechias, in 5 eyes (11.9%). All IOLs were well centered postoperatively. CONCLUSION: The short-term data suggest implantation of the AcrySof single-piece hydrophobic acrylic IOL is safe in the pediatric eye.

Cataract↗
PubMed1996

Scanning electron microscopic analysis of foldable acrylic and hydrogel intraocular lenses.

OBJECTIVE: To analyze the surface quality of foldable acrylic and hydrogel intraocular lenses (IOLs). SETTING: Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, and Institute of Anatomy and Cellular Biology, University of Giessen, Germany. METHODS: We studied eight foldable IOL models with optics made of six different acrylate/methacrylate polymers: Acrylens ACR360 (loptex), AcrySof MA60BM (Alcon), MemoryLens U940A (Mentor), 92S and 92C (Morcher), Hydroview H60M (Storz), HydroSof SH30BC (Alcon), and ISH66 (Corneal). Four IOLs of each design were examined. Light and scanning electron microscopy were performed before and after IOL folding with forceps. RESULTS: All IOL models had excellent optic and haptic surfaces. The haptic-optic junctions revealed minimal empty spaces or irregularities in three of the five three-piece IOLs and smooth surfaces in all one-piece IOLs. Minimal surface alterations and superficial defects caused by folding were detectable in the two acrylate (acrylic) IOLs (loptex ACR360, Alcon MA60BM) with low water content. CONCLUSION: Intraocular lenses of acrylate/methacrylate polymers had excellent surface quality. The acrylic IOLs were vulnerable to mild folding or forceps defects; however, these were less marked than those previously noted with poly(methyl methacrylate) IOLs.

Lenses, Intraocular↗
PubMed2004

Quartz crystal microbalance and infrared reflection absorption spectroscopy characterization of bisphenol A absorption in the poly(acrylate) thin films.

The absorption process of bisphenol A (BPA) in a number of poly(acrylate) thin films, such as poly(2-methoxyethyl acrylate) (PMEA), poly(ethyl acrylate) (PEA), poly(n-butyl methacrylate) (PBMA), and poly(methyl methacrylate) (PMMA), has been investigated by quartz crystal microbalance (QCM) and infrared reflection absorption spectroscopy (IRRAS) measurements. Both QCM and IRRAS measurements show that the BPA molecules absorb in PMEA, PEA, and PBMA thin films but not in PMMA thin film. The differences in the BPA absorption behavior are mainly attributed to the difference in the glass transition temperature (T(g)) between these polymers. This absorption behavior also depends on the BPA concentration and polymer film thickness. Furthermore, IRRAS characterization demonstrates that the hydrogen bonding is formed between the hydroxyl group in BPA and the carbonyl group in the poly(acrylate) thin films. BPA molecule absorbed in these polymer thin films can be removed by ethanol rinse treatment. By optimizing experimental conditions for the QCM electrode modified by PMEA thin film, detection limitation of approximately 1 ppb for BPA can be realized by the in situ QCM measurement. This method is expected to be a sensitive in situ detection way for trace BPA in the environmental study.

Journal Article↗
PubMedDate not supplied

Michael reaction of chitosan with various acryl reagents in water.

A Michael reaction of chitosan was conducted in water containing acetic acid with various acryl reagents. The degree of substitution could be controlled by temperature, reaction time, and the amount of acryl reagents. Although the modified chitosan derivatives with acrylic acid esters showed water-solubility, that with poly(ethylene glycol) acrylate, however, turned to water-insoluble material by lyophilization. Good biodegradation was observed in modified chitosan derivatives by standard activated sludge.

Acylation↗
PubMed2003

Hydroxy- and silyloxy-substituted TEMPO derivatives for the living free-radical polymerization of styrene and n-butyl acrylate: synthesis, kinetics, and mechanistic studies.

The synthesis of new 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) styryl derivatives as mediators for the living free-radical polymerization is described. Two of the alpha-methyl groups at the 2- and 6-position of the parent TEMPO styryl alkoxyamine have been replaced by hydroxymethyl and silyloxymethyl groups. To further increase the steric hindrance around the alkoxyamine oxygen atom, the remaining two methyl groups have been substituted with larger ethyl groups. Styrene polymerizations using hydroxy-substituted TEMPO derivatives are fast, but are not well-controlled. As previously shown for other OH-substituted alkoxyamines, intramolecular H-bonding leads to an acceleration of the C-O bond homolysis and, hence, to an acceleration of the polymerization process. However, the OH groups also increase the alkoxyamine decomposition rate constant. The kinetics of the C-O bond homolysis have been determined using EPR spectroscopy. Decomposition studies have been conducted with the aid of 1H NMR spectroscopy. In contrast to the OH-substituted alkoxyamines, highly hindered silyloxy-substituted TEMPO alkoxyamines turned out to be excellent mediator/initiators for the controlled styrene polymerization. Polystyrene with M(n) of up to 80 000 g/mol and narrow polydispersities (PDI) has been prepared using the new alkoxyamines. Reactions have been conducted at 105 degrees C; however, even at 90 degrees C controlled but slow polymerizations can be achieved. Furthermore, and more importantly, poly(n-butyl acrylates) with narrow PDIs (<1.15) have been prepared at 105 degrees C with the new alkoxyamines. Controlled acrylate polymerization can be conducted at temperatures as low as 90 degrees C. The silylated alkoxyamines presented belong to the most efficient initiator/mediators for the controlled acrylate polymerization known to date. The effect of the addition of free nitroxide on the acrylate polymerization is discussed. Moreover, the synthesis of diblock copolymers with narrow PDIs is described.

Journal Article↗
PubMed2005

A study of the surface region of the Mo-V-Te-O catalysts for propane oxidation to acrylic acid.

The bulk mixed Mo-V-Te oxides possess high activity and selectivity in propane oxidation to acrylic acid and represent well-defined model catalysts for studies of the surface molecular structure-activity/selectivity relationships in this selective oxidation reaction. The elemental compositions, metal oxidation states, and catalytic functions of V, Mo, and Te in the surface region of the model Mo-V-Te-O system were examined employing low energy ion scattering (LEIS) and X-ray photoelectron spectroscopy (XPS). This study indicated that the surfaces of these catalysts are terminated with a monolayer, which possesses a different elemental composition from that of the bulk. The rates of propane consumption and formation of propylene and acrylic acid depended on the topmost surface V concentration, whereas no dependence of these reaction rates on either the surface Mo or Te concentrations was observed. These findings suggested that the bulk Mo-V-Te-O structure may function as a support for the unique active and selective surface monolayer in propane oxidation to acrylic acid. The results of this study have important practical consequences for the development of improved selective oxidation catalysts by introducing surface metal oxide components to form new surface active V-O-M sites for propane oxidation to acrylic acid.

Journal Article↗
PubMed2006

Estimation of the optimum loading of an antibiotic powder in an acrylic bone cement: gentamicin sulfate in SmartSet HV.

BACKGROUND: In some countries, commercially available antibiotic powder-loaded acrylic bone cement is routinely used in joint replacement, while, in others, "off-label" formulations are used in selected procedures (where the antibiotic powder is blended manually with the powder of a plain cement in the operating room/theater by either the surgeon or approved personnel). In the latter situation, an arbitrary rather than a rational approach is used for deciding on the amount of the antibiotic that is blended with the cement powder (herein referred to as "the antibiotic powder loading"). METHODS AND RESULTS: The first objective of this study was to present two methods for estimating the optimum loading of gentamicin sulfate powder that may be blended manually with the powder of a commercially available acrylic bone cement, ABC (Wopt). The second objective was to define the challenges associated with each of these methods. The loading (W) was optimized with respect to two key properties of the cured cement that were obtained simultaneously, namely (1) fatigue life in phosphate-buffered saline solution (PBS) at 37 degrees C, and (2) the rate of elution of the gentamicin from the cement (E) in that medium. Three sets of specimens were used, containing 2.25, 4.25 and 11.50 wt/wt% of the gentamicin that was blended manually with the cement powder. The fatigue tests involved determining the number of cycles at which a specimen fractured (Nf) when subjected to fully-reversed tension-compression sinusoidal load, +/- 15 MPa at 2 Hz. E was determined from the concentration of gentamicin in the PBS solution when the specimen fractured, using fluorescence polarization immunoassay for the measurement. Consistent with a priori expectations, it was found that, with increase in W, Nf decreased while E increased. Two approaches for obtaining an estimate of Wopt are described, a mathematical method and an empirical one, that lead to Wopt values of 6.50 wt/wt% and 4.78 wt/wt%, respectively. Thus, this antibiotic loading ranges from about the same to about 92% greater than that in SmartSet GHV Gentamicin, which is a commercially available bone cement used clinically and which has the same composition as SmartSet HV except for the presence of gentamicin sulfate in its powder (blended in by the manufacturer). INTERPRETATION: We present and critically compare two rational methods of determining the optimum loading of an antibiotic powder in an acrylic bone cement, which should serve as a guide when using "off-label" antibiotic powder-loaded acrylic bone cements in cemented joint replacements.

Anti-Bacterial Agents↗
PubMed1996

Acrylic cranioplasty using miniplate struts.

OBJECTIVE: Cranioplasty using acrylic is a common procedure in patients with cranial defects secondary to trauma, infection, or tumor. The limitations of this technique include poor adherence of the acrylic to surrounding bone and difficulty in achieving a proper cosmetic contour in complicated cranial defects, especially those involving the orbital rim. The authors have been continually developing techniques of cranioplasty. METHODS: Ten consecutive cranioplasties were performed over the past 5 years using this new technique. TECHNIQUE: The authors describe a technique using miniplates as struts to which the acrylic is applied using a "reinforced concrete" principle. RESULTS/CONCLUSION: All patients achieved excellent cosmetic results with no complications. This technique allows contour of the repair site while the acrylic is curing and provides a more resilient resulting prosthesis.

Bone Cements↗
PubMed1986

Effect of saliva and serum on the adherence of Candida species to chlorhexidine-treated denture acrylic.

The effect of saliva and serum on the adherence of five strains of Candida albicans and one each of C. tropicalis and C. glabrata to chlorhexidine-pretreated acrylic was measured in vitro. A four-fold dilution of saliva or serum significantly inactivated the fungicidal effect of chlorhexidine gluconate. Pretreatment of the acrylic with unstimulated mixed saliva for 30 min led to a reduced adherence for all the Candida strains tested, whilst a similar pretreatment with serum slightly increased adhesion. Moreover treatment of saliva- or serum-coated acrylic with chlorhexidine gluconate 2% reduced adherence by between 19% and 86%. The inhibition of yeast adherence by chlorhexidine persisted for up to 19 days after the exposure of the acrylic strips to the disinfectant.

Adhesiveness↗
PubMed1984

Comparison of the absorption and metabolism of sulphasalazine and acrylic-coated 5-amino salicylic acid in normal subjects and patients with colitis.

Serum levels of 5-amino salicylic acid ( 5ASA ) and acetyl 5ASA have been measured in volunteers after ingestion of sulphasalazine (6 g) and compared with levels after an equivalent dose of acrylic coated 5ASA (2.4 g). The serum levels of both 5ASA and acetyl 5ASA were similar after each preparation apart from an early peak of 5ASA following acrylic coated 5ASA . Serum and urinary levels for 5ASA and acetyl 5ASA have been measured in colitic patients following equivalent doses of sulphasalazine and acrylic coated 5ASA . Serum levels were similar; 25% of the calculated ingested 5ASA was excreted in the urine after sulphasalazine compared with 20% following acrylic coated 5ASA .

Adult↗