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PubMed1983

An in vitro and in vivo study of the effect of incorporation of chlorhexidine into autopolymerizing acrylic resin plates upon the growth of Candida albicans.

Chlorhexidine acetate was incorporated into autopolymerizing acrylic resin and, after studying its ability to diffuse out in vitro, an investigation was made into the potential of the mixture to treat palatal candidosis in the rat. Chlorhexidine was found to diffuse out of acrylic in fungicidal concentrations for up to three weeks when mixed with the acrylic powder in the proportion of 7.5% (w/w). At this concentration it was found that palatal candidosis as produced by the technique of Shakir et al. was cured or prevented. However, rats fitted with chlorhexidine supplemented plates were found not to take sufficient food during the experimental period to maintain their body weight.

Acrylic Resins↗
PubMed1994

Mutagenicity of ethanolic extracts of used acrylic dentures.

The in vivo physicochemical sorption of mutagenic substances onto acrylic polymers was investigated in worn acrylic dentures. Thus, ethanolic extracts of acrylic dentures from 41 of a total of 69 human donors (60%), were found mutagenic in the standard plate incorporation Salmonella mutagenicity test against either TA98 or TA100 strains. Denture extracts from smokers produced mutagenicity more often than the ones from non-smokers (75% vs. 45%, P 0.01). Mutagenicity was preferentially directed against TA98 (TA98:TA100 = 2.9:1, P < 0.0005). Predilection for TA98 was more pronounced in denture extracts from non-smokers (4.7:1) than from smokers (2.0:1). When direct mutagenicity was observed, it was reduced by the rat-liver S9. Induced mutant yields were 6.1 +/- 3.9 and 7.0 +/- 8.9 times higher than the spontaneous for TA98 and TA100 respectively (smokers, 50-cm2 denture surface area eq./plate+S9). Denture extracts from smokers induced higher levels of mutation than the ones from non-smokers (TA98 + S9, smoker:non-smoker = 2:1, P < 0.01). Mutagenicity was associated with longer periods of denture usage (P 0.007). Thus, denture poly(methyl methacrylate) base material can adsorb mutagenic substances, possibly from diet and tobacco, which are extractable by ethanol. Theoretically, the in situ alcoholic desorption and recirculation of carcinogenic mutagens may have a contributory role in certain cases of intra-oral and upper alimentary tract carcinogenesis.

Acrylic Resins↗
PubMed1989

Reduction and fixation of jaw fractures using acrylic splints.

This paper proposes the criteria for application of acrylic splints in the treatment of various types of maxillofacial fractures. These were based mainly on the number of remaining teeth that are important for the restoration of occlusion. The acrylic splints studied consisted of intermaxillary, lingual and labiolingual types that hold a dental arch and a cap type that covers a dental arch. It was found that the intermaxillary type was best indicated for the loss of multiple teeth, the lingual type for the predicted intraversion of bone fragments and the labiolingual as well as cap types for the deciduous or mixed dentition. Clinical application based on the above standard, which was attempted in our 60 patients, produced successful results. In addition, the usefulness of these acrylic splints as an intraoral apparatus was discussed.

Acrylic Resins↗
PubMed1990

The use of antimicrobial acrylic strips in the nonsurgical management of chronic periodontitis.

Evidence to date has demonstrated the potential value of acrylic strips to deliver antimicrobial compounds into periodontal pockets. The present study was designed to evaluate further the therapeutic effect of antimicrobial acrylic strips in the management of chronic periodontitis. A total of 101 pockets in 69 patients were randomly treated with (1) chlorhexidine strips, (2) metronidazole strips, (3) tetracycline strips, (4) root planing, and (5) combined root planing and metronidazole strips. Immediately before and after treatment clinical measurements of disease were recorded over a three-month period. For all treatment groups significant improvements in clinical parameters were seen compared to control untreated sites but the most effective treatment was combined root planing and metronidazole and the least effective chlorhexidine. Although not significant, combined root planing and metronidazole also appeared to produce some adjunctive effects on clinical parameters compared to root planing alone. Antimicrobial acrylic strips appear useful treatments for chronic periodontitis, but should be used primarily as an adjunct to conventional root planing.

Acrylic Resins↗
PubMed1991

Physical characterization of acrylic bone cement cured with new accelerator systems.

In the attempt to substitute dimethyl-p-toluidine (DMPT), a toxic tertiary aryl-amine accelerator, into the formulation of acrylic cements, less toxic accelerator systems are developed. These systems consist of benzoyl peroxide (BPO) and unsaturated tertiary-aryl-amines, such as acryloyl- (ANP) and methacryloyl-(MNP) N-phenylpiperazine, which can be chemically incorporated in the polymerizing resin or, at least, result in less leaching from cured materials. In this work compressive mechanical properties and ageing tests for colour stability of acrylic cement cured with BPO and ANP or MNP have been considered. For compressive tests, cylindrical specimens were cured with BPO and equivalent molecular amounts of DMPT, ANP and MNP. Compressive yield stress (sigma y), strain at yield (epsilon y, %) and elastic modulus (E) gave very similar results for samples cured with DMPT and ANP, and slightly lower results for samples cured with MNP. In colour stability tests, the samples (disks of 1.5 cm diameter) were exposed to UV light at different irradiation times (up to 42 h). The evaluation of the colour change was performed with a digital analyser for images, and observed under scanning electron microscopy. From the obtained results, ANP appeared to be the best candidate as accelerator in the preparation of biomedical acrylic resins and composites.

Acrylic Resins↗
PubMed1991

The prenatal inhalation toxicity of acrylic acid in rats.

Pregnant Sprague-Dawley rats (5 per groups) were exposed in a pretest to 0, 225, and 450 ppm acrylic acid (AA) and in a main study (30 per group) to 0, 40, 120, and 360 ppm acrylic acid. Exposures were for 6 hr/day, during Days 6 to 15 of gestation (period of organogenesis), with further observation up to Day 20 after mating. Maternal toxicity occurred in animals exposed at 450 and 225 ppm in the pretest. At 360 ppm in the main study maternal toxicity consisted of sensory irritation (discharge from the eyes, snout wiping, and restless behavior) with significant reductions in body weight (p less than 0.01), body weight gain (p less than 0.01), and food consumption (p less than 0.01) relative to that of chamber controls. Effects on body weight and body weight gain were dose-related and when corrected for uterus weight were significant in animals exposed to 120 ppm (p less than 0.01), with an effect on body weight gain also at 40 ppm (p less than 0.05), indicating a minimal maternal toxic effect. There were no signs of group-related trends or significant differences between groups in terms of numbers of preimplantation losses, live fetuses, or resorptions, and no signs of group-related differences in the incidences of abnormalities, variations, or retardations in the fetuses in terms of general appearance and the condition of the internal organs or the skeletons. It is concluded that under the experimental conditions of the main study acrylic acid vapor at concentrations between 40 and 360 ppm had no embryotoxic teratogenic effects on Sprague-Dawley rats. Maternal toxicity was minimal at 40 ppm, clearer at 120 ppm, and more pronounced at 360 ppm.

Abnormalities, Drug-Induced↗
PubMed1987

Aquatic toxicity of acrylates and methacrylates: quantitative structure-activity relationships based on Kow and LC50.

Recent EPA scrutiny of acrylate and methacrylate monomers has resulted in restrictive consent orders and Significant New Use Rules under the Toxic Substances Control Act, based on structure-activity relationships using mouse skin painting studies. The concern is centered on human health issues regarding worker and consumer exposure. Environmental issues, such as aquatic toxicity, are still of concern. Understanding the relationships and environmental risks to aquatic organisms may improve the understanding of the potential risks to human health. This study evaluates the quantitative structure-activity relationships from measured log Kow's and log LC50's for Pimephales promelas (fathead minnow) and Carassius auratus (goldfish). Scientific support of the current regulations is also addressed. Two monomer classes were designated: acrylates and methacrylates. Spearman rank correlation and linear regression were run. Based on this study, an ecotoxicological difference exists between acrylates and methacrylates. Regulatory activities and scientific study should reflect this difference.

Acrylates↗
PubMed1992

Genetic toxicology of acrylic acid.

Acrylic acid was tested for gene mutations in the in vitro CHO/HGPRT assay, for chromosome aberrations in CHO cells in culture, and for potential to induce unscheduled DNA synthesis in rat hepatocytes in culture. In vivo assays performed included the Drosophila sex-linked recessive lethal assay by both the feeding and injection routes, the in vivo cytogenetic assay in rat bone marrow cells after both a 1-day and 5-day oral dosing regimen, and a dominant lethal assay in mice by both an acute and 5-day dosing regimen. All results were negative (non-mutagenic) except for the in vitro chromosome aberration assay. This latter result is consistent with the previously reported possible clastogenic activity suggested by the results of the mouse lymphoma L5178Y TK locus assay in which a predominance of small-colony mutants was observed (Moore et al., Environmental and Molecular Mutagenesis 1988, 11, 49-63). The rapid clearance of acrylic acid in animals and the weight of evidence of genetic toxicity testing, including negative in vivo data in both somatic and germ cells, indicate a lack of genetic toxicity of acrylic acid in vivo.

Acrylates↗
PubMed1991

Evaluation of acrylic strips containing amoxycillin with clavulanic acid for local drug delivery.

The in vitro release of amoxycillin with clavulanic acid from acrylic strips at initial concentrations of 30, 40 and 50 per cent w/w was monitored using a double-beam ultraviolet spectrophotometer and compared with release of tetracycline hydrochloride. Highest levels of the antibacterial agents were released during the first 24 h period. Therapeutic levels of the drugs continued to be released during the subsequent 9 day period and were shown to be biologically active. Furthermore, for amoxycillin with clavulanic acid, an initial concentration of 40 per cent gave the highest level of release on day 10; while, for tetracycline, 50 per cent provided the highest level of release. Local application of 40 per cent amoxycillin with clavulanic acid incorporated into acrylic strips placed in periodontal pockets in patients with established periodontitis produced a marked change in the subgingival microflora as monitored by dark-field microscopy and cultural techniques. These changes in the subgingival flora were concomitant with elimination of bleeding on probing at the treated sites and were still evident 3 weeks after removal of the acrylic strips. The sensitivity of Bacteroides gingivalis (syn. Porphyromonas gingivalis) and Bacteroides intermedius (syn. Prevotella intermedia) isolated before and after treatment to amoxycillin with clavulanic acid remained unchanged.

Acrylic Resins↗
PubMedDate not supplied

Resistance of attached Escherichia coli to acrylic acid and its significance for the survival of plasmid-bearing organisms in water.

As previously reported, free organisms of Escherichia coli are sensitive to damage and killing when exposed to acrylic acid in water. The effect of the agent was greatest in distilled water, but there was a marked effect in effluent and seawater also. The effect was temperature-dependent, with organisms exposed at 4 degrees C being much less affected than those exposed at 20 degrees C. The above sensitivity was for free organisms, but those attached to glass beads were resistant to acrylate. This resistance applied equally to attached plasmid-free and attached plasmid-bearing organisms, but is likely to be more significant for plasmid-bearing strains because some plasmids studied here stimulated bacterial attachment. The likely significance of the acrylate resistance of attached organisms for enterobacterial survival in the aquatic environment, e.g. in the vicinity of shellfish beds, is discussed.

Acrylates↗
PubMed1996

Improved dose distribution with a universal acrylic breast compensator.

Wedge filters frequently do not provide optimal distribution in the chest wall, lung, and areolar-nipple complex because they extend through the entire width of tangential radiation fields for breast cancer. In addition, medial wedge filters increase dose to the contralateral breast. In order to overcome these shortcomings, a new method of acrylic compensation was investigated. A universal acrylic breast compensator (ABC) was designed, with patient data, to extend anteriorly from the central axis. To accurately display build-up data, the ABC was entered into the treatment planning system as a wedge filter. Dose homogeneity within the compensated breast, chest wall, and lung volumes was assessed using 3-D planning and dose volume histograms. Dose to the contralateral breast was evaluated using thermoluminescent dosimetry in a polystyrene phantom. Opened, wedged, and compensated conditions were irradiated using the above described techniques. Due to lack of extension of the ABC posteriorly to the central axis (allowing lung inhomogeneity to correct for increased patient thickness), ABCs reduced the high dose regions in the chest wall and lung as compared to wedge filters. ABCs reduced hot spot in the areolar-nipple complex more efficiently as compared to wedge filters. ABCs also reduced dose to the contralateral breast by more than 20% relative to wedge filters. Wedge filters can be inefficient because of lung transmission and contour topography. Excessive dose to the chest wall, lung, and areolar-nipple complex, and contralateral breast can be alleviated with the use of a universal acrylic breast compensator. Its convenience and dosimetric advantages both in treatment planning and daily application offer a useful tool in the management of breast cancer.

Acrylic Resins↗
PubMed2006

Allergy to auto-polymerized acrylic resin in an orthodontic patient.

This article reports on a 60-year-old woman who had an allergic reaction to methylmethacrylate self-curing acrylic resin during orthodontic treatment. A localized hypersensitive reaction appeared on the palate after an orthodontic retainer was placed. Samples of the acrylic were removed and analyzed with gas chromatography to evaluate the residual monomer level. The residual monomer content was between 0.745% and 0.78%, which did not exceed international standards for this material. Patch tests were performed with several methylmethacrylate resin samples and processed with various techniques; they showed positive reactions. Despite the many alternative products available, self-curing acrylic resin remains widely used because of its low cost, ease of use, and diversity of indications. Orthodontists should be aware that allergic reactions can occur.

Acrylic Resins↗
PubMedDate not supplied

Preparation of acrylic grafted chitin for wound dressing application.

Chitin grafted with poly(acrylic acid) (chitin-PAA) was prepared with the aim of obtaining a hydrogel characteristic for wound dressing application. The chitin-PAA films were synthesized at various acrylic acid feed contents to investigate its effect on water sorption ability. Acrylic acid (AA) was first linked to chitin, acting as the active grafting sites on the chain that was further polymerized to form a network structure. The evidences of grafting were found from FTIR and solid state 13C NMR spectra. The TGA results exhibited the high degradation temperature of the grafted product suggesting the formation of a network structure. The degree of swelling (DS) of chitin-PAA films was found in the range of 30-60 times of their original weights depending upon the monomer feed content. The chitin-PAA film with 1:4 weight ratio of chitin:AA, possessed optimal physical properties. The cytocompatibility of the film was investigated with a cell line of L929 mouse fibroblasts. The morphology and behavior of the cells on the chitin-PAA film were determined after different time periods of culture up to 14 days. The L929 cells proliferated and attached well onto the film. These results suggested that the 1:4 chitin-PAA has a potential to be used as a wound dressing.

Acrylic Resins↗
PubMed2006

Crosslinked carboxymethylchitosan-g-poly(acrylic acid) copolymer as a novel superabsorbent polymer.

A novel carboxymethylchitosan-g-poly(acrylic acid) (CMCTS-g-PAA) superabsorbent polymer was prepared through graft polymerization of acrylic acid onto the chain of carboxymethylchitosan and subsequent crosslinking. It was demonstrated by FTIR spectroscopy that acrylic acid had been graft polymerized with carboxymethylchitosan. The thermal stability of the polymer was characterized by thermogravimetric analysis. By studying the swelling ratio of the polymer synthesized under different conditions, optimization conditions were found for a polymer with the highest swelling ratio. The rate of water absorption of the polymer was high, and the swelling of the polymer fitted the process of first dynamics. The swelling ratio of the polymer was pH-dependent.

Absorption↗
PubMed2006

Determination of acrylamide and acrylic acid by isocratic liquid chromatography with pulsed electrochemical detection.

The electrochemical behaviour of the polycrystalline platinum electrode towards the oxidation/reduction of short-chain unsaturated aliphatic molecules such as acrylamide and acrylic acid was investigated in acidic solutions. Analytes were separated by reverse phase liquid chromatographic and quantified using a pulsed amperometric detection. A new two-step waveform, is introduced for detection of acrylamide and acrylic acid. Detection limits (LOD) of 20 nM (1. 4 microg/kg) and 45 nM (3.2 microg/kg) were determined in water solutions containing acrylamide and acrylic acid, respectively. Compared to the classical three-step waveform, the proposed two-step waveform shows favourable analytical performance in terms of LOD, linear range, precision and improved long-term reproducibility. The proposed analytical method combined with clean-up procedure accomplished by Carrez clearing reagent and subsequent extraction with a strong cation exchanger cartridges (SPE), was successfully used for the quantification of low concentrations of acrylamide in foodstuffs such as coffee and potato fries.

Acrylamide↗
PubMed2006

Characterization of acrylic resins used for restoration of artworks by pyrolysis-silylation-gas chromatography/mass spectrometry with hexamethyldisilazane.

A procedure based on the technique of the pyrolysis-GC/MS has been applied, in this work, in order to determine the composition of synthetic acrylic resins employed in artworks. The method is based on the on line derivatization of these resins using hexamethyldisilazane (HMDS). Results obtained have been compared with those others from direct pyrolysis and in situ thermally assisted hydrolysis and methylation with tetramethylammonium hydroxide (TMAH). Sensitivity using HMDS as derivatising reagent is found similar to that from direct pyrolysis and methylation with TMAH. Better resolution of the most representative peaks has been also obtained. Additionally, this method reduces the formation of free acrylic acid molecules during the pyrolysis process and, in consequence, more simplified and well-resolved chromatograms are obtained. Finally, the reported procedure has been successfully used for characterizing several acrylic-based varnishes and binding media currently used in Fine Arts and real pictorial samples from graffiti performed on a Middle Ages bridge.

Acrylic Resins↗
PubMed2004

Does plasma irradiation improve shear bond strength of acrylic resin to cobalt-chromium alloy?

OBJECTIVES: Plasma treatment leads to surface modification such as the improved wettability of dental materials. Studies have suggested that plasma treatment may bring about an improvement in the shear bond strength between cobalt-chromium alloy and self-curing acrylic resin. METHODS: Forty-eight cobalt-chromium alloy specimens were randomly divided into four groups (each of the groups consisted of 12 specimens); air abrasion, adhesive primer, adhesive primer after air abrasion, or after plasma irradiation. A self-curing acrylic resin, 2 mm thick and 3.6 mm in diameter, was processed on all specimens before storage in distilled water at 37 degrees C for 24 h. Shear bond strength values were determined at a crosshead speed of 0.5 mm/min. Data was statistically analyzed using Scheffé's test. RESULTS: Adhesive primer clearly increased the shear bond strength compared with air abrasion (p < 0.05). The synergy of air abrasion and adhesive primer greatly increased the shear bond strength, showing a five-fold increase over air abrasion, or one and a half-fold over adhesive primer. A similar tendency in increase was observed in the adhesive primer after plasma treatment, but to a lower degree. Adhesive primer after plasma treatment showed half the shear bond strength of the treatment of adhesive primer after air abrasion (p < 0.05). Moreover, adhesive primer after plasma treatment showed a lower shear bond strength than adhesive primer alone although the difference was not statistically significant. SIGNIFICANCE: Plasma treatment does not improve adhesion between cobalt-chromium alloy and self-curing acrylic resin.

Acrylic Resins↗
PubMed2004

Functional outcomes of acrylic intraocular lenses in pediatric cataract surgery.

PURPOSE: To evaluate the functional outcomes of in-the-bag implantation of acrylic intraocular lenses (IOLs) with posterior continuous curvilinear capsulorhexis (PCCC), without PCCC, with PCCC and anterior vitrectomy, and with PCCC and optic capture in pediatric cataract surgery. SETTING: Pediatric Ophthalmology Service, Guru Nanak Eye Centre, New Delhi, India. METHODS: Forty-two eyes of 25 children were included in this prospective study. All eyes had in-the-bag implantation of an AcrySof IOL (Alcon). Twenty-five eyes had had an anterior continuous curvilinear capsulorhexis (ACCC) (Group A). Seventeen eyes had PCCC along with ACCC (Group B), 4 had anterior vitrectomy combined with PCCC (Group C), and 6 had PCCC with IOL optic capture through the PCCC (Group D). Secondary opacification of the visual axis, visual acuity, and possible complications were observed and analyzed. RESULTS: The mean age of the patients was 78 months (range 36 to 144 months). The mean follow-up was 13 months (range 6 to 18 months). Four eyes (16%) in Group A developed visually significant posterior capsule opacification (PCO) involving the central visual axis and required secondary capsulotomy. All eyes in Groups B, C, and D had a clear visual axis at the last follow-up and did not require a secondary procedure. Minimal postoperative inflammation (ie, aqueous flare and IOL deposits ) was seen in all groups. The mean preoperative decimal best corrected visual acuity (BCVA) in Groups A, B, C, and D was 0.095, 0.055, 0.174, and 0.039, respectively. Postoperatively, the BCVA was 0.54, 0.66, 0.66, and 0.66, respectively. CONCLUSIONS: An optimal-sized ACCC followed by in-the-bag implantation of a foldable acrylic IOL helped maintain a clear visual axis by delaying the onset of PCO and leading to milder PCO. The benefits of a foldable acrylic IOL in pediatric cataract surgery can be increased by combining it with PCCC, with or without anterior vitrectomy, or with optic capture of the IOL.

Acrylic Resins↗