[Acrylic prostheses in epiphysial surgery. II. Failures after reconstruction of the hip with an acrylic prosthesis].
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Hip↗
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[Casting acrylic crowns in the mouth with use of translucent odus-acryl-crowns].
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Crowns↗
Relative developmental toxicities of acrylates in rats following inhalation exposure.
The developmental toxicities of seven acrylates were studied in Sprague-Dawley rats after inhalation exposure for 6 h/day, during days 6 to 20 of gestation. The exposure concentrations were: for acrylic acid, 50, 100, 200, or 300 ppm; for methyl acrylate, 25, 50, or 100 ppm; for ethyl acrylate, 25, 50, 100, or 200 ppm; for butyl acrylate, 100, 200, or 300 ppm; for ethylhexyl acrylate, 50, 75, or 100 ppm; for hydroxyethyl acrylate, 1, 5, or 10 ppm; and for hydroxypropyl acrylate, 1, 5, or 10 ppm. No treatment-related increases in embryo/fetal mortality or fetal malformations were observed after exposure to any of these acrylates. Fetal toxicity, indicated by reduced fetal body weight, was observed after exposure to 300 ppm acrylic acid, 100 ppm methyl acrylate, 200 ppm ethyl acrylate, and 200 or 300 ppm butyl acrylate in the presence of overt signs of maternal toxicity. While there was evidence of maternal toxicity, no significant developmental toxic effects were observed after exposure to ethylhexyl acrylate, hydroxyethyl acrylate, or hydroxypropyl acrylate at any concentration. These results indicate that inhaled acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, ethylhexyl acrylate, hydroxyethyl acrylate, and hydroxypropyl acrylate are not selectively toxic to the embryo or fetus.
Acrylates↗
Contribution to the biological assessment of orthodontic acrylic materials. Measurement of their residual monomer output and cytotoxicity.
The acrylic materials used in orthodontics for the fabrication of removable appliances are subjected in the oral cavity to processes of change which influence their physical, mechanical and biological properties. It is therefore essential that every newly developed material must be judged in terms of its clinical value. In the present study, 2 orthodontic cold-cure acrylics, Orthocryl and Forestacryl, and 4 orthodontic photocure acrylics, Triad, Wil-O-Dont, Odontolux and Lux-A-Tech, were investigated and compared with 2 prosthetic acrylic materials: the cold-cure acrylic Palapress and the hot-cure acrylic Paladon. The quantity of residual monomers from methyl methacrylate (MAA) or urethane dimethacrylate (UDMA) eluted from the sample in a given time after the processing was estimated by high pressure liquid chromatography (HPLC). The cytotoxic properties of the materials were examined by Mosmann's proliferation-inhibition test with an established culture of fibroblasts (= MTT test). The hot-cure acrylic Paladon produced by far the smallest amount of eluted residual monomer and the least growth inhibition in the MTT test. The prosthetic cold-cure acrylic Palapress achieved significantly better results than the orthodontic cold-cure materials Orthocryl and Forestacryl. The photocure acrylics released less UDMA than did the cold-cure acrylics MMA. In the cell culture test, all the orthodontic materials examined were assessed as "slightly cytotoxic"; the prosthetic acrylics were graded under ISO-standard 10993-5 as "noncytotoxic". After soaking the plastic material in water for 3 days its cytotoxic properties, as exemplified by the cold-cure acrylic Forestacryl and the photocure acrylic Triad, were reduced, and during the following investigation no more inhibition of growth was observed. It was possible to confirm with the tests used that, for Triad, it is necessary to carefully remove the oxygen-inhibition layer of the photocure acrylic in order to improve the biological properties. The influence of the plastic material on fibroblast cultures was assessed, among other methods, by the quantity of residual monomers liberated. These were significantly reduced after soaking the manufactured substance in water for 3 days. Careful laboratory treatment of the photocure acrylics is necessary in order to improve their biological properties.
Acrylic Resins↗
The influence of morphological variation on Candida albicans adhesion to denture acrylic in vitro.
Using denture acrylic pieces coated with either whole human stimulated saliva or oral streptococci, the binding ability of three different Candida albicans strains was investigated. The C. albicans strains include a clinical isolate with the commonly observed, smooth, round colonial morphology (strain 613p), a morphological variant spontaneously derived from the clinical isolate strain 613p (strain 613m1BK) and a clinical isolate from an oral lesion that was also a morphological variant upon primary isolation (strain 228). Levels of adhesion to the acrylic pieces were determined radiometrically using C. albicans cells metabolically labelled with [35S]-methionine. Whole stimulated saliva significantly increased the binding of all strains compared to uncoated acrylic. However, the level of binding of strain 613p to saliva-coated acrylic was significantly greater than the levels observed for the morphological variant strain 613m1BK. Coating acrylic pieces with either Streptococcus sanguis NCTC 10904, Strep. mutans GS-5 or Strep. sobrinus ATCC 27352 instead of saliva resulted in significantly greater binding by strain 613p compared to uncoated acrylic. Pre-coating the acrylic with the oral streptococci did not significantly increase the binding of morphological variant strains 613m1BK and 228 compared to uncoated acrylic. In general, preincubation of adherent streptococci with sucrose to induce the synthesis of extracellular carbohydrate polymers did not significantly increase the binding levels of the C. albicans strains above those observed using streptococci in buffer alone. Compared to its parental strain 613p, morphological variant strain 613m1BK adhered poorly to denture acrylic coated with either salivary constituents or oral streptococci, while strain 228 adhered to the same substrates at an intermediate level. Furthermore, physical disaggregation of clusters of the morphological variant strain 613m1BK did not appear to increase its binding capacity to saliva-coated denture acrylic. The effect of whole stimulated saliva on the adherence of C. albicans 613p to a variety of plastic substrates in addition to denture acrylic was examined. Overall, saliva pre-coating of the various plastics promoted C. albicans 613p adhesion. The adhesion of strain 613p to denture acrylic coated with whole stimulated saliva from each of five different donors or with parotid and submandibular/sublingual saliva from each of two donors was also examined. Regardless of donor, a coating of whole stimulated saliva significantly increased the binding of strain 613p to denture acrylic compared to uncoated acrylic. In addition, a coating of parotid saliva significantly increased the binding of strain 613p to denture acrylic compared to submandibular/sublingual saliva.
Acrylic Resins↗
Cross-reactions of multifunctional methacrylates and acrylates.
Dental acrylic monomers (that is, acrylates and methacrylates) are important occupational sensitizers. Acrylic monomers may also cause allergic reactions in dental care. Unfortunately, acrylic monomers cross-react--that is, allergic sensitization induced by one acrylic compound extends to one or more other acrylic compounds. Therefore, sensitized individuals are often multiallergic and, accordingly, cannot be exposed to any of the compounds. In the present review aspects of cross-reactivity in general and data from animal studies of cross-reactivity of multifunctional methacrylates and acrylates are summarized. A multitude of acrylic monomers is used in dentistry, and when patients or dental personnel become sensitized, it is of great importance to identify the dental acrylic preparations to which the sensitized individual can be exposed. Sensitized dental workers are known to have ceased working in dentistry owing to occupational allergic contact dermatitis or asthma, caused by dental acrylic monomers. Unfortunately, cross-reactivity of acrylic monomers used in dentistry is not sufficiently mapped to enable selection of an appropriate compound for the sensitized person. Another important aspect is that product declarations of dental acrylic materials should show all acrylic compounds present in the products--even acrylic monomers/impurities with lower concentrations than 1%. This could help to select a product that the sensitized individual could use.
Acrylates↗
[Comparative analysis of tissue reaction to acrylic resin materials in studies on Wistar strain rats].
The study takes up the issue of assessing rat tissue reaction to operatively inserted implants of different acrylic resin materials used in prosthetic dentistry. The materials subjected to analysis were polyacrylics: Vertex Soft, Vertex R.S., Vertex S.C., Superacryl and silicone material Molloplast B. The prolongation of life and the dynamic development of prosthetic treatment have caused removable dentures to be used longer and among more people. Polymerised acrylic resin material of these dentures is a potential pathogenic factor to the oral cavity mucosa which is in contact with it. As many as 20 to 70% of patients using removable acrylic dentures suffer from prosthetic stomatopathy. It is considered that the mucosa irritation may be caused by denture trauma, a mycotic infection or toxic action of some components of acrylic materials. Therefore the use of new generation acrylic materials in producing prosthetic dentures needs a precise assessment of undesirable local and systemic effects. A comparative analysis of the effect of correctly polymerised acrylic material on rat mucosa, parotid glands and lymphatic nodes was carried out. Systemic toxicity of these materials was assessed. Acrylic plates were prepared from the most often used acrylic resin materials in the Department of Prosthetic Dentistry PAM and a silicone material (these materials were polymerised precisely according to the producers instruction). Before implantation the plates underwent a thermodynamic analysis in order to ensure that the polymerisation process was carried out correctly and to determine thermal resistance of particular materials. Next sterile acrylic plates were implanted in rats under general anaesthesia. The animals were divided into 6 groups, 10 rats each. In four groups acrylic plates were implanted, in one group silicone material plates were implanted and it represented the comparative group, in one control group an incision of the buccal mucosa was made. The rats were observed during a period of 6 weeks, they were weighed every two weeks and no loss in body mass was noted (Tab. 1). After 6 weeks the rats were anaesthetised with ether and dissectioned. Biopsy specimens were taken from the buccal mucosa, porotid gland and lymphatic cervical nodes around the plates in order to make histological specimens. Blood samples were also taken to carry out blood cell counts and liver tests to determine eventual systemic toxicity of the studied acrylics. Histological specimens were stained with hematoxylin and eosin. In borne cases in order to precisely assess the intercellular substance other staining methods were used such as van Gieson, PAS and silvering of precollagen fibres on reticulum. Prepared specimens were assessed in a light microscope in magnification of 80 to 400. Basing on specimens of the control group an analysis of tissue reaction to the particular tested acrylic resin material was carried out. It was ascertained that the most irritative properties to the rat buccal mucosa were caused by self-cure acrylic material--Vertex S.C. This polymer caused in all rats in the tested group a reactive hypertrophy of cervical lymphatic nodes (Tab. 2 and Fig. 3). The least damaging effect on the surrounding tissues was caused by heat-cured acrylic resin material Superacryl (Fig. 4). The tested materials had no damaging effect on the rat parotid gland and did not have a toxic action on the internal organs.
Acrylic Resins↗
Potentiation by triorthotolyl phosphate of acrylate ester-induced alterations in respiration.
The purpose of this study was to determine whether triorthotolyl phosphate (TOTP), an inhibitor of carboxylesterases, would enhance the inhibitory effects of acrylate esters on respiration. Respiratory frequency was measured and the calculated decreases in respiratory frequency were used as an index of respiratory irritancy due to acrylate compounds. Tidal volume, minute ventilation, and rectal temperature were also measured. Dose-dependent decreases in frequency were found in rats inhaling methyl acrylate, ethyl acrylate and acrylic acid. Tidal volume was also reduced in rats exposed to acrylate compounds and, as a result, the percentage change in minute ventilation was greater than the percentage change in frequency or tidal volume alone. Pretreatment with TOTP (125 mg/kg) enhanced the decreases in frequency and minute ventilation caused by acrylate esters but not those resulting from exposure to acrylic acid. Exposure to ethyl acrylate and acrylic acid also resulted in dose-dependent reductions in rectal temperature. TOTP potentiated ethyl acrylate-induced decreases in rectal temperature but not those caused by acrylic acid. The results suggest that inhibition of carboxylesterases can result in enhanced irritant action of acrylate esters on the upper respiratory tract, and provide support for a local role of carboxylesterases in the detoxification of these irritant esters.
Acrylates↗
Dissipation of heat during polymerization of acrylics used for external skeletal fixator connecting bars.
OBJECTIVE: To determine the amount of heat conducted by transfixation intramedullary pins (IP) and Kirschner wires (KW) during polymerization of acrylics used for external skeletal fixator (ESF) connecting bars. STUDY DESIGN: Thermal conduction was measured using thermistors applied to IP and KW surfaces during the polymerization phase of acrylics. METHODS: Type II ESF were created from IP or KW placed into wooden dowels and plastic tubing used to create connecting bars filled with one of two types of acrylic (Acrylic Pin External Fixation System or Technovit, Jorgensen Laboratories, Loveland, CO). Thermistors were positioned on the acrylic column surface and on IP or KW surfaces 5 or 10 mm from the acrylic column. Five ESF test groups were created. The maximum temperature (Tmax) of the acrylic column (Tmax-A), IP (Tmax-IP), KW (Tmax-KW), and duration that Tmax-IP or Tmax-KW remained greater than or equal to 55 degrees C were calculated. RESULTS: All IP and KW thermistors placed 5 mm from acrylic columns reached mean temperatures greater than 50 degrees C and had peak temperature ranges greater than 55 degrees C compared with all IP and KW thermistors placed 10 mm from the acrylic columns in all groups. Thermistors placed 5 mm from the acrylic column in two groups maintained temperatures greater than 55 degrees C for greater than or equal to 0.5 minute. CONCLUSIONS: Acrylic columns positioned 5 mm from a thermistor on a IP or KW had the potential to reach or exceed temperatures that have been reported to cause thermal necrosis of tissues. CLINICAL RELEVANCE: Acrylic Pin External Fixation System or Technovit acrylic connecting bars used in ESF designs have the potential to cause thermal injury to soft and bony tissue by thermal conduction along transfixation pins or wires.
Acrylic Resins↗
Theories of posterior tooth selection: porcelain versus acrylic.
The salient physical properties of porcelain and acrylic posterior teeth and their clinical correlations have been reviewed. However, the practitioner has alternative choices to the use of all porcelain or all acrylic denture teeth in complete dentures; like materials need not oppose each other. Porcelain and acrylic teeth can be used in combination with each other. However, consideration should be given to the following observations: Myerson claims that when acrylic opposes porcelain teeth, the acrylic wears less than porcelain opposing porcelain or acrylic opposing acrylic teeth. Ortman states that his clinical experience suggests that acrylic opposing porcelain wears more rapidly than the other two types of relationships. In support of Myerson , Peyton and Craig suggest that "the lowest coefficients of friction are obtained when porcelain and acrylic specimens oppose each other." At present, no statistically significant research has been published to support or refute these statements. In an attempt to more successfully harmonize the wearability of materials, gold occlusal surfaces can be cast and attached onto acrylic posterior teeth. Through this effort the wearability of opposing acrylic teeth will be enhanced, while at the same time centric and balancing occlusal contacts will be refined and the occlusal vertical dimension maintained. Lauciello describes a technique for the placement of functionally generated amalgam stops as restorations within mandibular acrylic teeth. Once again , this is an attempt to give a clinically practical solution to improve the efficiency and wearability of acrylic posterior teeth.(ABSTRACT TRUNCATED AT 250 WORDS)
Acrylic Resins↗
Sensitization to patch test acrylates.
Data on allergic contact dermatitis from acrylates and 4 patients sensitized during routine patch testing are reported. During 1982-1985, we used 7 different acrylates for tests. 1 patient out of 22 (= 4.5%) was sensitized to ethyl acrylate and butyl acrylate (1% pet.). Since September 1985, we have used a commercial (meth)acrylate series containing 28 substances. 3 of 24 patients tested became sensitized to ethyl acrylate, 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate (0.5% pet.). Because active sensitization with acrylates can be very harmful, it may be necessary to use lower concentrations than recommended. Currently, we test ethyl acrylate, 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate at 0.167% pet.
Acrylates↗
Metabolism of acrylate to beta-hydroxypropionate and its role in dimethylsulfoniopropionate lyase induction by a salt marsh sediment bacterium, Alcaligenes faecalis M3A.
Dimethylsulfoniopropionate (DMSP) is degraded to dimethylsulfide (DMS) and acrylate by the enzyme DMSP lyase. DMS or acrylate can serve as a carbon source for both free-living and endophytic bacteria in the marine environment. In this study, we report on the mechanism of DMSP-acrylate metabolism by Alcaligenes faecalis M3A. Suspensions of citrate-grown cells expressed a low level of DMSP lyase activity that could be induced to much higher levels in the presence of DMSP, acrylate, and its metabolic product, beta-hydroxypropionate. DMSP was degraded outside the cell, resulting in an extracellular accumulation of acrylate, which in suspensions of citrate-grown cells was then metabolized at a low endogenous rate. The inducible nature of acrylate metabolism was evidenced by both an increase in the rate of its degradation over time and the ability of acrylate-grown cells to metabolize this molecule at about an eight times higher rate than citrate-grown cells. Therefore, acrylate induces both its production (from DMSP) and its degradation by an acrylase enzyme. (1)H and (13)C nuclear magnetic resonance analyses were used to identify the products resulting from [1-(13)C]acrylate metabolism. The results indicated that A. faecalis first metabolized acrylate to beta-hydroxypropionate outside the cell, which was followed by its intracellular accumulation and subsequent induction of DMSP lyase activity. In summary, the mechanism of DMSP degradation to acrylate and the subsequent degradation of acrylate to beta-hydroxypropionate in the aerobic beta-Proteobacterium A. faecalis has been described.
Acrylates↗
Occupational allergic contact dermatitis caused by photobonded sculptured nails and a review of (meth) acrylates in nail cosmetics.
BACKGROUND: Mono(meth)acrylates (monoacrylates and monomethacrylates) are moderate to strong sensitizers. They are used in the production of a great variety of polymers, including nail cosmetics. OBJECTIVE: A patient who became occupationally sensitized to photobonded sculptured nails is reported. Detailed patch testing and analyses of the patient's nail cosmetics containing mono(meth)acrylates clarified the cause of her hand and face dermatitis. The current knowledge on mono(meth)acrylates in nail cosmetics is also reviewed. METHODS: Patch testings with conventional methods, including patch testing with the patient's own substances, were performed. The patient's nail cosmetics suspected of containing mono(meth)acrylates were analyzed with gas chromatography/mass spectrometry analysis. RESULTS: In the (meth)acrylate series, 15 of the 31 (meth)acrylate compounds tested gave an allergic reaction: 2 acrylates, 5 methacrylates, 3 dimethacrylates, and 5 diacrylates. Epoxy diacrylates, cyanoacrylate, triacrylates, and methacrylic acid were negative. Three of seven of her own nail cosmetic preparations contained mono(meth)acrylates as revealed by the gas chromatography/mass spectrometry analysis, and these also gave allergic patch test reactions, namely, the nail liquid, nail hardener, and UV-cured nail gel. CONCLUSION: The patient probably had been sensitized to the following (meth)acrylate compounds from her nail cosmetics: tripropylene glycol diacrylate and methyl acrylate from her photobonded nail gel; ethyl methacrylate, triethylene glycol dimethacrylate, and methyl methacrylate from her nail liquid; and butyl methacrylate from her nail hardener. She was probably also sensitized to the rare sensitizer aliphatic urethane diacrylate, but the source was not verified. Because nail cosmetics containing mono(meth)acrylates are strong sensitizers, both the workers and the customers should be aware of their sensitizing capacity; they should use no-touch techniques regarding the skin before the mono(meth)acrylates are polymerized.
Acrylates↗
Water sorption by maxillary acrylic resin denture base and consequent changes in vertical dimension.
Many kinds of materials have been tried in the Laboratory and to some extent clinically prior to introduction of acrylic resin. With the introduction of acrylic resin as denture base material, continuous attempts have been made to evaluate its physical properties. To observe the changes in vertical measurements of acrylic resin dentures due to water sorption and to assess variations of vertical movements of individual teeth within dentures due to water sorption; present study was carried out on 25 maxillary acrylic dentures. From results, the maximum water sorption appears to take place within 24 hours and after 28 day of water sorption; there is no change in vertical dimension if the denture is placed for further more time. With the introduction of acrylic resin as denture base material continued attempts have been made to evaluate physical properties so as to determine its suitability as an ideal nonmetalic denture base materials. Several investigations have been carried out on physical properties of this material such as compressive strength, tensile strength, solubility and colour stability. These have proved their superiority over other nonmetalic denture base materials used so far. Also several studies have been carried out to assess dimensional changes that occur in acrylic resin during processing, but very few studies have been carried out about the water sorption changes in the acrylic resin and still few about the vertical dimensional changes in acrylic resin due to water sorption. While fabricating the denture base from the acrylic resin, it comes in contact with water during polishing as well as cleaning, consequently during the use of denture it is constantly wetted by oral fluids. It is the hypothesis that water sorption by denture base acrylic may effect the retention and stability of the denture. It has been shown that water molecules act according to the laws of diffusion. The diffusion presumably occurs between the macromolecules which are forced slightly apart. This separation renders the molecules mobile and the inherent stresses created during heat curing of the acrylic resin can be relieved with consequent intermolecular relaxation and possible changes in the shape of the denture. Exposure time also plays a significant role in water sorption. The present investigation was therefore, carried out by keeping the following objectives: (1) The primary objective was to observe the changes in vertical measurements of acrylic resin dentures due to water sorption. (2) To assess the variations of vertical movement of individual teeth within the dentures due to water sorption.
Absorption↗
Inhibitory effects and biotransformation of acrylic acid in computer-controlled pH-stat CSTRs.
In this study, the inhibitory effects and anaerobic biotransformation of acrylic acid in computer-controlled pH-stat completely stirred tank reactors (CSTRs) with two different cultures, namely unacclimated and acrylate-acclimated acetate-enriched Methanosarcina and homogenized (crushed) granular cultures, were investigated. The microbial acclimation, influent concentration, and loading rate of acrylic acid were studied in the experiments. The experimental results revealed that methanogenic cultures at a concentration of 3200 +/- 80 mg/L as volatile suspended solids (VSS) could be acclimated to acrylic acid up to a loading rate of 220 mg/L per day (0.068 g acrylic acid/g VSS per day) in the presence of a constant acetate concentration of 2000 +/- 200 mg/L as the primary substrate after 300 days of acclimation. The same cultures (680 +/- 80 mg/L as VSS), after 80 days of acclimation to acrylic acid as the sole carbon source, transformed acrylic acid up to the loading rate of about 200 mg/L per day (0.29 g acrylic acid/g VSS per day) almost completely (>99%) to acetic and propionic acid, but could not effectively metabolize these intermediate products. Acrylate-acclimated homogenized granular cultures (6900 +/- 80 mg/L as VSS) effectively metabolized 2200 mg/L per day (0.32 g acrylic acid/g VSS per day) of acrylic acid, as the sole carbon source, after 50 days of severe inhibition.
Acrylates↗
Results and complications of hydrophobic acrylic vs PMMA posterior chamber lenses in children under 17 years of age.
PURPOSE: To compare results and complications of implantation of hydrophobic acrylic foldable intraocular lenses in children with those of polymethylmethacrylate (PMMA) intraocular lenses. METHODS: In a retrospective study, we analyzed results of cataract surgery with posterior chamber lens implantation in 30 eyes of 30 patients aged 1-16 years. In 10 eyes, acrylic (Alcon AcrySof) intraocular lenses, and in 20 eyes, single-piece PMMA posterior chamber lenses were implanted. Indications for cataract surgery (blunt or penetrating trauma, zonular cataract, cataracta polaris posterior, posterior lenticonus) and mean age at implantation were comparable in the two groups. Mean patient age at surgery was 8.6+/-4.6 years (range 3-16 years) for the acrylic vs 6.3+/-4.3 years (range 1-16 years) for the PMMA group. Mean follow-up was 1.0+/-0.7 years (range 0.1-2.2 years) in the acrylic group and 1.8+/-1.5 years (range 0.1-5.7 years) in the PMMA group. Primary anterior vitrectomy was performed in 7 eyes in the PMMA group and in 3 eyes in the acrylic group. In addition, one additional posterior capsulorhexis without anterior vitrectomy was performed in each group. Primary outcome measure was the occurrence of postoperative "complications" (fibrin, synechiae, posterior capsular opacification). For statistical evaluation, the Fisher exact test was used. RESULTS: When evaluating all complications together (at least one complication vs no complication), there were significantly less complications in the acrylic group (2 of 10 vs 15 of 20; p=0.007. For early complications (postoperative fibrin, synechiae) the difference was also significant (1 of 10 in the acrylic vs 11 of 20 in the PMMA group; p=0.02). The rate of posterior capsular opacification necessitating YAG capsulotomy was lower in the acrylic group (1 of 10 eyes) than in the PMMA group (7 of 20 eyes), but the difference did not reach statistical significance ( p=0.67). The postoperative time point of YAG capsulotomy was 21 months in the acrylic group and 19+/-10 months (range 6-33 months) in the PMMA group. IOL dislocation was not observed in any of the patients. Postoperative visual acuity was comparable in the two groups: 0.57+/-0.35 (0.03-1.0) in the acrylic vs 0.39+/-0.34 (0.001-0.9) in the PMMA group ( p=0.83). CONCLUSIONS: Implantation of hydrophobic acrylic intraocular lenses in the capsular bag in children may be associated with less postoperative complications compared with implantation of PMMA lenses. This appears also to be true in children under age 6 years. The visual results seem comparable and correspond mainly to the underlying ocular pathology.
Acrylates↗
Effects of inhaled acrylic acid derivatives in rats.
Chemical reactivity with glutathione, urinary thioether excretion, total (T-SH) and non-protein-SH (NP-SH) groups in tissues and blood glucose were studied in male Wistar rats exposed to acrylic acid derivatives. The 6-h inhalation of acrylonitrile (AN), methyl acrylate (MA), ethyl acrylate (EA), n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2-EHA) in several concentrations increased the urinary thioether excretion; the portion metabolized to thioethers was 35-18% of the acrylonitrile dose, but only 1.5-8% for the acrylates. Total-SH levels in the liver significantly decreased after the inhalation of AN, EA, BA and 2-EHA. In blood there was a decrease only after EA. Most pronounced NP-SH depletion was in the liver, less in blood and moderate in brain and lungs. There was an exponential relationship between the tissue NP-SH and the inhaled concentrations. Calculated concentrations inducing 50% NP-SH depletion indicated that reaction of acrylic acid derivatives with SH groups was decreasing in the order AN much greater than 2-EHA greater than EA = BA for the chemicals and liver greater than blood greater than lungs greater than brain for the tissues. All inhaled acrylates induced hyperglycemia, but acrylic acid was without effect. The chemical reactivity of acrylates with glutathione (GSH) decreased in the order EA greater than BA greater than MA greater than AN greater than 2-EHA. The results suggest that GSH depletion may participate in acute lethal and biochemical toxic effects of acrylic acid esters.
Acrylates↗
Comparative study of silicone versus acrylic foldable lens implantation in primary glaucoma triple procedure.
OBJECTIVE: To compare silicone versus acrylic foldable intraocular lens (IOL) implantation in primary glaucoma triple procedure (PGTP). DESIGN: Prospective, randomized. PARTICIPANTS: A total of 79 eyes of 79 primary open-angle glaucoma (POAG) patients in need of combined surgery were randomized to a silicone IOL group (36 eyes) and acrylic IOL group (43 eyes). INTERVENTION: The study eyes underwent PGTP, which consisted of primary trabeculectomy, phacoemulsification, and posterior chamber IOL implantation. Adjunctive mitomycin C (MMC) (0.5 mg/ml for 1 minute) was used selectively only in patients with one or more risk factors for filtration failure of PGTP. MAIN OUTCOME MEASURES: Snellen visual acuity, intraocular pressure (IOP), slit-lamp biomicroscopy, and number of glaucoma medications were measured, performed, or determined preoperatively and at regular intervals postoperatively. RESULTS: There were no significant differences in the mean number of postoperative glaucoma medications at 1, 2, 3, 4-6, and 9-12 months and at last follow-up (P > 0.05); mean change in corrected visual acuity best attained (P = 0.315) or at last follow-up (P = 0.223) between the silicone and acrylic groups. Both groups had significant decreases in mean IOP and mean number of medications postoperatively at all times (P < 0.05). However, the postoperative IOP > 25 mmHg and IOP spike > 5 mmHg above preoperative IOP during the first month were significantly higher in the acrylic group (P = 0.026). The mean postoperative IOP at 1 month in the acrylic group was also significantly higher than the silicone group (14.1 +/- 5.0, 11.2 +/- 3.9, P = 0.005). Conversely, there were no significant differences in mean postoperative IOP at 2, 3, 4-6, and 9-12 months and at last follow-up between the silicone and acrylic groups (P > 0.05). Suture removal or release occurred significantly more frequently in the acrylic IOL group during the first month and the first 2 months (48.8% and 60.5%) than the silicone group (25.0% and 36.1%, P = 0.030 and 0.031, respectively). There were no significant differences in postoperative complications or surgical interventions between the two groups (P > 0.05). CONCLUSIONS: During the first year following the PGTP with selective use of MMC, there were no significant differences in the medical dependency or visual outcomes or complications between the silicone and acrylic groups. Both groups attained significant decreases in IOP postoperatively. However, the mean IOP was significantly higher in the acrylic than the silicone group at 1 month postoperatively, and postoperative IOP > 25 mmHg and IOP spike > 5 mmHg above preoperative IOP were significantly greater in the acrylic group. There were significantly more suture releases in the acrylic IOL group than the silicone IOL group in the first 2 months postoperatively.
Acrylic Resins↗