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PubMedDate not supplied

Posterior capsular opacification in pseudophakic eyes with a silicone or acrylic intraocular lens.

PURPOSE: To compare posterior capsular opacification in eyes with IOL of two different materials--silicone or acrylic. METHODS: Eighty consecutive eyes undergoing cataract surgery were prospectively randomized in two groups, 40 eyes receiving a silicone (Sl--30NB) and 40 eyes an acrylic (Acrysof MA60BM) intraocular lens (IOL). The same surgeon performed phacoemulsification and the intraocular lens (PHACO IOL) operation in all cases. Patients were re-examined on the first postoperative day, after one week, four months, and 1-2.4 years. Seven eyes were lost to late control. RESULTS: Clinically significant posterior capsular opacification (PCO) (including eyes with capsulotomy already performed) was equally common in both groups; 25% in the silicone group and 19% in the acrylic group (p=0.53). The posterior capsule remained clear in 61% of the silicone and 76% of the acrylic IOL eyes (p=0.18). In the whole study group, 29% of eyes with and 14% without concurrent ocular diseases had significant PCO (p=0.13). In the silicone IOL group, PCO was more common in eyes with concurrent ocular diseases (44%) than eyes without other diseases (10%) (p=0.049). Eyes with acrylic IOL showed no difference in significant PCO, with or without other diseases (18% and 20%, respectively). CONCLUSIONS: In a consecutive series of 80 cataract eyes central PCO was equally common in eyes receiving a silicone or an acrylic IOL. In the silicone IOL group, however, significant PCO was more common if there was concurrent ocular disease, while with the acrylic IOL concurrent ocular disease did not seem to increase the risk of PCO.

Acrylic Resins↗
PubMed2001

Patient preference for light-cured composite bite splint compared to heat-cured acrylic bite splint.

BACKGROUND: Heat-cured acrylic has been the most commonly used material for construction of bite splints. Although effective, its processing involves several steps and is time consuming. Furthermore, acrylic splints distort easily if not kept in water when not worn for long periods of time. A newly developed light-cured composite material is now being used for bite splint fabrication. The composite material offers benefits in ease and speed of construction, has minimal warping and distortion, and has proven patient acceptance. The aim of this study was to determine if patient satisfaction with the composite splint was as good as, or preferential to, the acrylic splint. METHODS: Both a composite and an acrylic bite splint were fabricated for each of 10 patients. The splints were worn alternately on a nightly basis and were adjusted as needed after the first week. After 3 weeks, each patient completed a questionnaire regarding the properties of each splint and any preferences they had in reference to fit, comfort, and other parameters of satisfaction. RESULTS: All of the patients were able to wear at least one of the splints comfortably. All 10 preferred the composite splint over the acrylic splint, agreeing that it felt more natural and was more comfortable to wear. CONCLUSIONS: The light-cured composite bite splint is preferable from the patient's perspective to the heat-cured acrylic bite splint. The composite splint is rapidly constructed on the original model, easily seated, and comfortably worn. Other properties of composite material also make it preferable for long-term use. Future studies are necessary to evaluate the functional differences between the composite and acrylic splint.

Acrylic Resins↗
PubMedDate not supplied

The effect of chopped poly(methyl methacrylate) fibers on some properties of acrylic resin denture base material.

PURPOSE: The fracture of acrylic resin dentures remains an unresolved problem. Over the years, various approaches to strengthening acrylic resin have been suggested, including modifying or reinforcing the resin. The aim of this study was to investigate the effect of chopped poly(methyl methacrylate) (PMMA) fibers on some properties of acrylic resin denture base material. MATERIALS AND METHODS: PMMA in the form of fibers 0.75 mm in diameter and 5 mm in length was added to acrylic resin denture base material in various percentages to form a composite material. The influence on doughing and manipulation times and transverse strength was examined. The results were subjected to statistical analysis using a one-way analysis of variance and, where appropriate, the Scheffé test. RESULTS: The results showed that the doughing time was decreased by the addition of fibers, with the manipulation and setting times showing inconsistent changes. There was a significant difference between the materials in terms of the transverse strength. When the amount of PMMA fibers in the acrylic resin was increased, there was a decrease in the modulus of rupture and a decrease in the modulus of elasticity. The differences were shown to be statistically significant in some groups. CONCLUSION: The doughing time was decreased by the addition of fibers, while the manipulation and setting times showed inconsistent changes. The incorporation of chopped, randomly oriented PMMA fibers into acrylic resin had no advantage over the unmodified polymer in terms of strength and cannot be recommended as a reinforcing agent for acrylic resin denture base material.

Acrylic Resins↗
PubMed2004

Chelation in metal intoxication XLVI: synthesis of some alpha-mercapto-beta-substituted aryl acrylic acids and their in vitro cadmium chelating ability.

OBJECTIVE: To synthesize some new alpha-mercapto-beta-substituted aryl acrylic acids, characterize them and investigate their in vitro cadmium chelating ability. METHODS: Six alpha-mercapto-beta-substituted aryl acrylic acids were prepared by the alkaline hydrolysis of 5- (aryl methylene) rhodanines, obtained from the condensation of substituted aldehydes and rhodanine following the reported procedure. The new compounds were characterized by elemental analysis, infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy. The liver and kidney from cadmium chloride pre-administered rats were homogenized and their nuclear mitochondrial fraction (NMF) and supernatant cytosol fraction (SCF) were separated. A measured volume of each fraction was dialyzed separately using "dialysis sack" against buffered-KCl medium containing a compound in the final concentration of 1 x 10(-3) mol/L for 3 h at 37 degrees C. The whole content of "sack" was subjected to cadmium estimation following digestion with conc. Nitric acid was detected using flame atomic absorption spectrometer. RESULTS: The in vitro screening showed that alpha-mercapto-beta-(p-methoxyphenyl) acrylic acid (compound 2) and alpha-mercapto-beta-(m-methoxy, p-hydroxyphenyl) acrylic acid (compound 4) were more effective than alpha-mercapto-beta-thienyl acrylic acid (compound 1) and alpha-mercapto-beta-(p-dimethylaminophenyl) acrylic acid (compound 3) in mobilizing cadmium as their dialyzable chelates. The presence of a methoxy group on the phenyl moiety (compounds 2 and 4) increases the metal chelating ability of mercapto acrylic acids. CONCLUSIONS: Compounds 2 and 4 seem to have accessibility to the cellular system and capability of chelating-out the intracellularly bound cadmium.

Acrylates↗
PubMedDate not supplied

Effect of original water content in acrylic resin on processing shrinkage.

PURPOSE: The aim of this study was to determine the original water content of a supplied acrylic resin powder and a monomer and of dry heat-processed acrylic bars. The effect of the original water content of acrylic resin on processing shrinkage was also investigated. MATERIALS AND METHODS: Ten bar specimens were fabricated using dried and as-supplied (control) acrylic resins. The resins were polymerized and cooled, then weighed and measured to determine the amount of shrinkage. The initial water content of the specimens was determined by thorough drying, and results were compared with the Student ttest. RESULTS: The initial water content and processing shrinkage of the dried acrylic resin bars were both significantly lower (P < .0001) than those of the as-supplied acrylic resin bars. CONCLUSION: The processing shrinkage of acrylic resin made from dried constituents was significantly less than that of resin made from products as supplied by the manufacturer. However, it is not known if this change is of clinical significance.

Acrylic Resins↗
PubMed1997

The effect of acrylic nails on the measurement of oxygen saturation as determined by pulse oximetry.

Pulse oximetry (Spo2) is a simple, noninvasive method that is widely used to determine oxygen saturation in patients undergoing surgical procedures. Artificial acrylic nails have recently become fashionable to strengthen and lengthen nails. This study investigates the effect of unpolished acrylic nails on the measurement of oxygen saturation by pulse oximetry. Data were collected during a 3-month period. Thirty women, average age 32 years (range 18 to 61 years), were recruited at a high-volume nail salon in northwestern Pennsylvania. A baseline pulse oximetry reading was obtained on each subject's natural, unpolished fingernail using a Nellcor N-20/N-20P portable pulse oximeter (Nellcor Incorporated, Hayward, California). A licensed nail technician applied the acrylic compound to the same finger. After the compound had hardened in approximately 5 minutes, a second reading was obtained on the unpolished acrylic nail. The mean pulse oximetry reading at baseline was 97.33% and after acrylic nail application, 97.58%. Using a paired Student's t test, no statistically significant differences existed between readings. This study demonstrates that unpolished acrylic nails do not affect pulse oximetry measurements of oxygen saturation. Patients may not need to remove unpolished acrylic nails before surgery.

Acrylates↗
PubMed1996

Condensation on polymethylmethacrylate, acrylic polymer, and silicone intraocular lenses after fluid-air exchange in rabbits.

PURPOSE: Condensation occurs rapidly on silicone intraocular lenses (IOLs) after vitrectomy and fluid-air exchange in the presence of a posterior capsulotomy, severely limiting the retinal view. Foldable IOLs made of an acrylic polymer are now available. The authors compare the condensation and subsequent retinal view degradation after vitrectomy and fluid-air exchange in rabbit eyes implanted with polymethylmethacrylate (PMMA), soft acrylic polymer (ACRYSOF), and silicone IOLs. METHODS: Thirty rabbits underwent bilateral lens removal. Twenty PMMA, 20 acrylic polymer, and 20 silicone IOLs were implanted into the capsular bag. After three-port vitrectomy, eyes were randomly assigned to undergo a posterior capsulotomy or to an intact posterior capsule. Fluid-air exchange was performed, and the amount of condensation on the IOL surface and resultant retinal view was graded. Surgical maneuvers then were performed to decrease the condensation. These maneuvers included wiping the IOL surface with a soft-tipped cannula and coating it with viscoelastic. RESULTS: No condensation occurred on IOLs in eyes with an intact posterior capsule. Significantly more condensation occurred on IOLs in eyes with a capsulotomy, regardless of IOL type (P < 0.014). Wiping the condensation resulted in significantly less condensation and improved retinal view on the PMMA and acrylic IOLs when compared with the silicone IOLs (P < 0.024). Condensation was eliminated on all three IOL types after viscoelastic was applied. However, increased distortion of the retinal view was induced by the viscoelastic on the silicone IOL as compared with the other IOLs. CONCLUSIONS: Condensation and subsequent retinal image degradation occurs uniformly after vitrectomy, posterior capsulotomy, and fluid-air exchange in eyes with PMMA, acrylic, and silicone IOLs. Because the condensation can be eliminated most easily on acrylic IOLs compared with silicone IOLs, when foldable IOL techniques are used it is likely that an acrylic polymer IOL would be advantageous for those patients at risk for future vitreous procedures requiring fluid-air exchange.

Animals↗
PubMed2005

Diffusion of uncharged probe reveals structural changes in polyacids initiated by their neutralization: poly(acrylic acids).

The diffusion studies of the uncharged probe (1,1'-ferrocenedimethanol) have been successfully applied for the evaluation of the changes in the three-dimensional structure of poly(acrylic acids) of various molecular weights (ranging from 2000 to 4,000,000 g/mol) during their neutralization with a strong base. The qualitative picture of the macromolecule arrangement during the titration of the polyacids has been obtained from the conductometric measurements. The characteristic changes in the poly(acrylic acid) conductivity are practically the same for all polyacids examined and are in a very good agreement with the predictions of our theoretical model of the polyelectrolyte conductance. The transformation of the polyelectrolyte solution into the gel-like or gel phase has been investigated more quantitatively by tracing the changes in the diffusion coefficient of the uncharged probe redox system. The probe diffusivities, D, were determined using steady-state voltammetry at microelectrodes for a wide range of neutralization degree, alpha, of the polyacids tested. The dependencies of D versus alpha are of similar shape for all poly(acrylic acids). The first parts of the dependencies reflect a rapid increase in D (up to neutralization degree of either 45% for the lowest molecular-weight poly(acrylic acid) or 75-80% for other polyacids). They are followed by the parts of a slight drop in the diffusion coefficient. The changes in the probe diffusivity become stronger as the molecular weight of poly(acrylic acid) increases. The maximum probe diffusion coefficients are greater than the initial values in the pure polyacid solutions by 14, 24, 19, 30, and 28% for poly(acrylic acid) of molecular weights of 2000, 450,000, 1,250,000, 3,000,000, and 4,000,000 g/mol, respectively. The variation in the probe diffusion coefficient qualitatively follows the line of the changes in the macroscopic viscosity of the polyelectrolyte system. This is in contrast to the predictions of the Stokes-Einstein relation and, therefore, suggests that the changes in the probe diffusion rate are mainly due to the structural changes in the polyacrylate medium and the macromolecular rearrangements induced by the chemical, acid-base reaction. By adapting the obstruction model for diffusion in homogeneous gels, the transport characteristics of the probe were converted into the structural characteristics of the polyelectrolytic systems. It has been found that the most ordered structure of the polyelectrolyte, or in other words the most permeable structure, is obtained when poly(acrylic acid) is neutralized at 75-80%.

Journal Article↗
PubMed2001

Occupational dermatitis in dental personnel: contact dermatitis with special reference to (meth)acrylates in 174 patients.

Between 1995 and 1998, 174 dental personnel were referred as patients to the Department of Occupational and Environmental Dermatology, Stockholm. After clinical examination, 131 were patch tested with the Swedish standard series and 109 with a dental screening series. Furthermore, 137 were tested for IgE-mediated allergy to natural rubber latex (NRL). Hand eczema was diagnosed in 109/174 (63%), 73 (67%) being classified as irritant contact dermatitis and 36 (33%) as allergic. Further diagnoses included other eczemas, urticaria, rosacea, psoriasis, tinea pedis, bullous pemphigoid or no skin disease. 77/131 (59%) had positive reactions to substances in the standard series and 44/109 (40%) to substances exclusive to the dental series. 24/109 (22%) patients had positive reactions to (meth)acrylates, the majority with reactions to several test preparations. Reactions to HEMA (2-hydroxyethyl methacrylate), EGDMA (ethyleneglycol dimethacrylate) and MMA (methyl methacrylate) were most frequent. 9 of the 24 were positive only to (meth)acrylates, the remaining 15 also had reactions to allergens in the standard series. 23 of these had hand eczema and 1 facial eczema. In 17 of the 24 allergic to (meth)acrylates, the dermatitis had started in 1995 or later, in 15 within the previous 12 months. Of 8 who had been sick-listed, 7 also had a history of atopy and 6 were allergic to nickel. The most frequent allergens besides (meth)acrylates were nickel, cobalt, palladium, fragrance mix, colophonium and thiuram mix. Allergy to natural rubber latex was diagnosed in 14/137 (10%). In conclusion, irritant hand dermatitis was the dominant diagnosis. Contact allergy to (meth)acrylate was seen in 22% of the patch tested patients, with reactions to 3 predominant test substances. 1/3 of the patients with allergy to (meth)acrylates had been sick-listed for dermatitis, but in all these cases the (meth)acrylate allergy was seen together with atopy and/or further contact allergies.

Adult↗
PubMed2003

In situ EPR investigation of the addition of persistent benzyl radicals to acrylates on ZSM-5 zeolites. Direct spectroscopic detection of the initial steps in a supramolecular photopolymerization.

Photolysis of dibenzyl ketone derivatives adsorbed on ZSM-5 zeolites produces persistent benzyl radicals (initiator radicals), which add to methyl acrylates (monomers) to generate persistent adduct radicals. Both initiator and adduct radicals are readily observable by conventional steady-state EPR spectroscopy at room temperature and are persistent for time periods ranging from seconds to many days. The rate of the formation and the amount of the adduct persistent radical formed depends on the structure of the initiator radical (benzyl radical derivative) and the structure of the monomer (acrylate derivative). The lifetimes of the initiator and adduct radicals depend on the supramolecular structure of the radical@zeolite complex and the diffusion and reaction dynamics of the radicals in the complex. The most intense signal and highest addition rate to methyl acrylate were observed for the smallest initiator radical, the benzyl radical, because of its high mobility and relatively rapid diffusion within the internal zeolite surface. With increasing length of an alkyl chain (methyl, ethyl, and pentyl) on either the initiator (alpha position of the radical) or monomer (alkyl group of acrylate ester), the rate of radical addition to the monomer decreased, a result that is consistent with the decreased mobility and diffusion of the initiator radical or monomer. Deuterium isotope experiments and variation of the methyl acrylate concentration demonstrated that the initial adduct radical from methyl acrylate adds to another methyl acrylate to generate a secondary adduct radical, which, in turn, can continue to propagate to form a polymer that is cross-linked to the zeolite crystals. The results demonstrate that EPR can be a powerful tool for the direct in situ analysis of supramolecular photochemistry involving radicals rendered persistent by supramolecular steric effects. The latter eliminate the need for sophisticated flash photolysis equipment to investigate the structure and dynamics of reactive radicals and require only the use of simpler steady-state lamps.

Journal Article↗
PubMed2004

Comparison of Nd : YAG capsulotomy rates following phacoemulsification with implantation of PMMA, silicone, or acrylic intra-ocular lenses in four European countries.

PURPOSE: The aim of this study was to compare the incidence of Nd : YAG laser capsulotomy after cataract surgery according to the type of intra-ocular lens material (PMMA, silicone, hydrophilic acrylic, hydrophobic acrylic) implanted in four European countries (France, Italy, Germany, Spain). DESIGN: A retrospective record review. PARTICIPANTS: A review of 1525 patients (first operated eye), aged 50 to 80 years, operated on for cataract in 1996 or 1997 in 16 surgical centers (4 per country). METHODS: The study employed a retrospective cohort design. Charts were reviewed to collect information during at least a three-year period following cataract surgery to identify patients who underwent Nd : YAG laser capsulotomy postoperatively. MAIN OUTCOME MEASURES: Data on the type of intra-ocular lens implanted was extracted from the patient notes, as was the date and outcome of the Nd : YAG laser intervention. Kaplan-Meier survival curve analysis with the time to Nd : YAG laser was performed on the data. RESULTS A total of 1525 patients (first operated eye) were available for the study (n = 294 for hydrophilic acrylic, n = 384 for PMMA, n = 421 for hydrophobic acrylic, n = 426 for silicone). There was a highly statistically significant difference between the IOL groups for the incidence of posterior capsule opacification (p < 0.001) and for Nd : YAG laser treatment (p < 0.001). The mean delay of Nd : YAG laser treatment from the date of cataract operation was 2.48 years (+/-1.70, ranging from 0 to 5.88 years). The rate of Nd : YAG laser capsulotomy over the follow-up period was lowest in the hydrophobic acrylic group (7.1%), followed by silicone (16.2%), PMMA (19.3%) and hydrophilic acrylic (31.1%), respectively. CONCLUSIONS: A low incidence of posterior capsular opacification (PCO) and Nd : YAG laser treatment was detected in hydrophobic acrylic IOLs in comparison to three other types of IOLs implanted in a large cohort of persons with age-related cataract. Choice of IOL type may reduce the need for Nd : YAG laser treatment, although further research on the reasons for this is needed.

Aged↗
PubMed2002

Shear bond strength of bis-acryl composite provisional material repaired with flowable composite.

BACKGROUND: Time and expense are considerable when refabrication of a bis-acryl composite provisional prosthesis is required, so an effective method of repair is desirable. Attempts at self-repair have been ineffective, and no reports of repair specific to bis-acryl composites were found in the literature. PURPOSE: To investigate the strength of a bis-acryl composite repair using flowable composite after two surface treatments and three storage conditions. MATERIALS AND METHODS: Thirty specimens of bis-acryl composite were made and divided into six groups. Half of the specimens received air abrasion only, and half received air abrasion followed by application of an intermediate bonding resin. A flowable composite was then applied to all specimens. Following three different storage conditions, the flowable composite was debonded using a universal testing machine in tensile mode. RESULTS: All specimens failed cohesively within the bis-acryl composite rather than at the repair interface. Surface treatment with air abrasion alone resulted in significantly higher shear bond strength values than when air abrasion and intermediate bonding resin were combined. Bond strength values were significantly higher in thermocycled specimens than in air-dried specimens. CONCLUSIONS: Use of air abrasion followed by application of flowable composite proved to be a successful technique for bis-acryl composite repair. CLINICAL SIGNIFICANCE: Repair of bis-acryl composite provisional material with a flowable composite is effective, expedient, and inexpensive.

Air↗
PubMed1986

NTP Carcinogenesis Studies of Ethyl Acrylate (CAS No. 140-88-5) in F344/N Rats and B6C3F1 Mice (Gavage Studies).

Ethyl acrylate is a monomer used to produce polymers and copolymers for use in latex paints, textiles, paper coatings, fabric finishes, dirt release agents, and specialty plastics. In 1980, 268 million pounds of ethyl acrylate were produced in the United States of which 209 million pounds were used by the producers and 59 million pounds sold. Carcinogenesis studies of ethyl acrylate were conducted by administering this test chemical in corn oil by gavage to groups of 50 male and 50 female F344/N rats and B6C3F1 mice at doses of 100 or 200 mg/kg. Ethyl acrylate was administered five times per week for 103 weeks. Groups of 50 rats and 50 mice of each sex received corn oil by gavage on the same schedule and served as vehicle controls. Survival of dosed male and female rats and mice was comparable with that of the corresponding vehicle controls. There was no evidence of systemic toxicity in the prechronic or in the 2-year studies. Compound-related increased incidences of hyperkeratosis, inflammation, and hyperplasia of the forestomach were observed in rats and mice in the prechronic as well as 2-year studies. In the 2-year studies, squamous cell papillomas and squamous cell carcinomas of the forestomach occurred at the site of chemical deposition with significant positive trends and increased incidences in dosed groups versus vehicle controls for both sexes of rats and mice. Nonneoplastic and neoplastic forestomach lesion frequencies were related to the concentration of ethyl acrylate in dosing solutions used. Significant negative trends for several common rodent tumors were found in treated animals in the 2-year studies. Under the conditions of these studies, ethyl acrylate was carcinogenic for the forestomach of F344/N rats and B6C3F1 mice, causing squamous cell carcinomas in male rats and male mice, squamous cell papillomas in male and female rats and male mice, and squamous cell papillomas or carcinomas (combined) in male and female rats and mice. Evidence for carcinogenicity was greater in males than in females. Ethyl acrylate also caused irritation of the forestomach mucosa in male and female rats and mice. Levels of Evidence of Carcinogenicity: Male Rats: Positive Female Rats: Positive Male Mice: Positive Female Mice: Positive Synonym: 2-propanoic acid, ethyl ester

Journal Article↗
PubMed1983

Allergic contact dermatitis due to urethane acrylate in ultraviolet cured inks.

Seven workers exposed to ultraviolet printing inks developed contact dermatitis. Six cases were allergic and one irritant. A urethane acrylate resin accounted for five cases of sensitisation, one of which was also sensitive to pentaerythritol triacrylate and another also to an epoxy acrylate resin. One instance of allergy to trimethylpropane triacrylate accounted for the sixth case of contact dermatitis in this group of workers. An irritant reaction is presumed to account for the dermatitis in the individual not proved to have cutaneous allergy by patch tests. In this instance trimethylpropane triacrylate was thought to be the most likely irritating agent. Laboratory investigation proved urethane acrylate to be an allergen. The results of investigations of the sensitisation potentials of urethane acrylate, methylmethacrylate, epoxy acrylate resins, toluene-2,4-diisocyanate, and other multifunctional acrylic monomers in the albino guinea pig are presented. The interpretation of such predictive tests is discussed.

Acrylates↗
PubMed1992

Inhibition of adherence of Candida albicans to acrylic by a chitin derivative.

The purpose of this study was to assess the effect of a chitin derivative (CSE) on the adherence of Candida albicans to acrylic. Fungal adherence to acrylic dentures is considered an essential step in the development of denture stomatitis. Adherence of C. albicans to acrylic pieces (5 x 5mm) was assessed microscopically using a calibrated ocular objective and expressed as number of adherent yeasts/mm2 of acrylic. CSE was prepared from commercial chitin (crab shell) and from chitin isolated from C. albicans blastospores. The effect of both CSE types on the adherence of C. albicans to acrylic was examined in two experimental systems: CSE present during the adherence assay and acrylic pieces pretreated with CSE prior to the assay. Both CSE types exerted a significant inhibitory effect when tested in the two experimental systems. These findings are significant for possible prevention of denture stomatitis.

Acrylic Resins↗
PubMed2000

Comparative in vitro cytotoxicity of ethyl acrylate and tripropylene glycol diacrylate to normal human skin and lung cells.

The potential for occupational exposure to the esters of acrylic acid (acrylates) is considerable, and, thus, requires a greater understanding of the their toxicity. Confluent (70-90%) cultures of normal human epidermal keratinocytes (NHEK), dermal fibroblasts (NHDF). or bronchial epithelium (NHBE) were exposed to the monofunctional ethyl acrylate (EA), the multifunctional tripropylene glycol diacrylate (TPGDA), or TPGDA monomer in a radiation curable lacquer (Lacquer A) at equimolar dosages in order to determine human in vitro cytotoxicity. Viability of the cells after 2-24-h exposure to the representative monofunctional or multifunctional acrylate or solvent control was used to calculate an index of acute cytotoxicity (50% inhibitory dose; ID50) and to determine the shape of the dose-response curves. TPGDA, Lacquer A, and EA were equally cytotoxic (ID50 is approximately equal to 0.1 micromol/cm2) to NHEK at equimolar doses. TPGDA or Lacquer A were more cytotoxic (is approximately equal to 100X) to NHDF or NHBE than EA. Sequential exposure of UV(A) and TPGDA to NHEK indicate the potential for a synergistic cytotoxic response. These findings are consistent with observed decreases in free sulfhydryl groups (e.g., glutathione or cysteine) that parallel the dose-response-related decreases in viability. logether, these data suggest possible differences in toxicity between the monofunctional EA and multifunctional TPGDA to NHEK, NHDF. or NHBE, possibly due to the difference in the number of functional acrylate groups and/or physicochemical differences (e.g., vapor pressure) between the acrylates investigated.

Acrylates↗
PubMed1991

Effects of laboratory disinfecting agents on color stability of denture acrylic resins.

This study determined the effects of chemical disinfecting agents on denture acrylic resins. Tested resins included the products CH Lucitone, Triad VLC, and Truliner. The disinfecting agents were sodium hypochlorite, Exspor, Cidex, and Wescodyne-D. Acrylic resin samples were placed in the various disinfecting agents and then evaluated for color changes at time intervals ranging from 15 minutes to 72 hours. No observable color change of any acrylic resin was seen before 2 hours. Both 1% sodium hypochlorite and 2% Cidex disinfectants produced the least discoloration of the acrylic resins, and Wescodyne-D disinfectant produced the most acrylic resin discoloration. Truliner resin discolored more than Triad VLC resin, and both underwent more color change than CH Lucitone resin. If manufacturers' recommended disinfecting times are followed, clinical and laboratory disinfection of acrylic resin dentures should cause no observable color change.

Acrylic Resins↗
PubMed1992

A physiologically based pharmacokinetic and pharmacodynamic model to describe the oral dosing of rats with ethyl acrylate and its implications for risk assessment.

A physiologically based pharmacokinetic and pharmacodynamic model has been developed to describe the absorption, distribution, and metabolism of orally dosed ethyl acrylate. The model describes the metabolism of ethyl acrylate in 14 tissues based on in vitro metabolic studies conducted with tissue homogenates. The routes of metabolism included in the model are carboxylesterase-catalyzed ester hydrolysis, conjugation with glutathione, and binding to protein. To adequately describe the rate and extent of glutathione depletion following gavage dosing, the steady-state rate of glutathione synthesis in the organs of interest was included. In vivo validation of the model was conducted by comparing the predictions of the model to the results of a variety of gavage dosing experiments with ethyl acrylate, including (1) the time course of glutathione depletion in a variety of tissues up to 98 hr following dosing at three dose levels, (2) the rate and extent of radiolabeled carbon dioxide excretion, and (3) protein binding in the forestomach. The very rapid metabolism predicted by the model was consistent with the observation that ethyl acrylate was metabolized too rapidly in vivo to be detected by common analytical techniques for tissue metabolite analysis. The validation data indicated that the model provides a reasonable description of the pharmacokinetics and the pharmacodynamic response of specific rat tissues following gavage dosing of ethyl acrylate. A dose surrogate, or measure of delivered dose, for ethyl acrylate was calculated and correlated with the incidence and severity of contact site toxicity (edema, inflammation, ulceration, and hyperplasia). The model provides a quantitative tool for evaluating exposure scenarios for their potential to induce contact-site toxicity, and it provides a quantitative approach for understanding the lack of toxicity in tissues remote from the dosing site.

Acrylates↗