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At least 217 records · Page 12Linked to original sources
PubMed1993

Occupational allergic contact dermatitis caused by exposure to acrylates during work with dental prostheses.

Between 1974 and 1992, we were consulted by 4 patients (an orthodontist, 2 dental technicians and a dental worker trained in-house) who had developed occupational allergic contact dermatitis from working with dental prostheses. All patients had positive allergic patch test reactions to methyl methacrylate (MMA), the acrylate which is the most widely used in work with prostheses. All but the orthodontist also reacted to dimethacrylates, which are used in cross-linked dental prostheses. The last patient, investigated in 1992, had been exposed mainly to light-cured acrylics, which are similar in composition to dental composite resins. These acrylics, only recently introduced into prosthetic work, contain more potent acrylic sensitizers than MMA. Accordingly, dental personnel working with prostheses may face a higher risk of sensitization than previously. To detect cases of occupational allergic contact dermatitis, we suggest that patients working with dental prostheses should be patch tested with MMA, 2-hydroxyethyl methacrylate, dimethacrylates, epoxy acrylates and urethane acrylates.

Acrylic Resins↗
PubMed1981

Relationship between cell surface composition of Candida albicans and adherence to acrylic after growth on different carbon sources.

The adherence of Candida albicans to acrylic was measured in vitro after growth of the yeast to stationary phase in defined medium containing glucose, sucrose, galactose, fructose, or maltose as the carbon source. In each case, yeast adherence was proportional to the concentration of sugar in the growth medium, but equimolar concentrations of different sugars promoted adherence to different extents. In vitro adherence was further increased by the addition of divalent cations to assay mixtures but was inhibited when saliva-treated acrylic strips were used or when yeasts were suspended in mixed saliva during the assay. The rate of spheroplast formation of yeasts grown in media containing a 500 mM concentration of the different sugars correlated well with the relative adherence of the cells to acrylic. Galactose-grown yeasts were most resistant to spheroplast formation with Zymolyase-5000 and most adherent to acrylic, whereas fructose-grown organisms were least resistant to spheroplast formation and least adherent to acrylic. These results indicate that when grown to stationary phase in media containing high concentrations of certain sugars, C. albicans undergoes a change in cell surface composition which facilitates its adherence to acrylic surfaces. Electron microscopy of yeasts harvested from such media revealed the presence of an additional surface layer which may be responsible for this enhanced adherence.

Acrylic Resins↗
PubMed1998

Adhesion of lens capsule to intraocular lenses of polymethylmethacrylate, silicone, and acrylic foldable materials: an experimental study.

AIMS: To investigate the adhesion characteristics of several intraocular lenses (IOLs) to the simulated and rabbit lens capsule. METHODS: Adhesive force to bovine collagen sheets was measured in water with polymethylmethacrylate (PMMA), three piece silicone, and acrylic foldable IOLs. In rabbit eyes, phacoemulsification and IOL implantation were performed. Three weeks later, adhesion between the anterior/posterior capsules and IOL optic was tested, and the capsule was examined histologically. RESULTS: The mean adhesive force to the collagen sheet was 1697 (SD 286) mg for acrylic foldable, 583 (49) mg for PMMA, and 0 mg for silicone IOLs (p = 0.0003, Kruskal-Wallis test). Scores (0-5) of adhesion between rabbit anterior capsule and IOL optic were 4.50 (0.55) for acrylic foldable, 3.20 (0.84) for PMMA, and 0.40 (0.55) for silicone IOLs (p = 0.004). Scores between rabbit posterior capsule and IOL optic displayed a similar tendency; 4.50 (0.84) for acrylic foldable, 3.00 (1.00) for PMMA, and 0.40 (0.55) for silicone IOLs (p = 0.021). Histological observation indicated that the edge of IOL optic suppressed the migration of lens epithelial cells towards the centre of the posterior capsule. This inhibitory effect was most pronounced with acrylic foldable IOL and least with silicone IOL. CONCLUSIONS: The acrylic foldable IOL adhered to the lens capsule more than the PMMA IOL, and the silicone IOL showed no adhesiveness. These differences seem to play a role in preventing lens epithelial cells from migrating and forming posterior capsule opacification.

Acrylic Resins↗
PubMedDate not supplied

Glare disability in patients with hydrophilic and hydrophobic acrylic intraocular lens implants.

PURPOSE: To compare glare disability test results in patients with hydrophilic and hydrophobic acrylic intraocular lenses (IOL). METHODS: Sixty eyes of 60 patients were studied in three groups of 20. Each eye in Group 1 had a single-piece hydrophilic acrylic (Bioacryl, Biotech, France) IOL implant, and each eye in Group 2 had a three-piece hydrophobic acrylic (AcrySof, Alcon, USA) IOL implant. Group 3 was the control group, and consisted of eyes without cataracts. Glare disability was tested using the Ophthimus glare sensitivity test (Ophthimus, Sweden). For each eye, we determined log contrast sensitivity values without exposure to glare source and with exposure to glare source. The difference between these values was recorded as the threshold contrast increase. An infrared camera was used to measure pupil diameter during glare disability testing, and pupil diameter greater than 4 mm was used as an exclusion criterion to eliminate edge design as a potential contributor to glare disability. RESULTS: The respective mean log contrast sensitivity scores for Groups 1, 2, and 3 in the absence of the glare source were 0.80 +/- 0.03, 0.81 +/- 0.04, and 0.79 +/- 0.08. The corresponding findings with glare source were 0.84 +/- 0.07, 0.89 +/- 0.07, and 0.84 +/- 0.03. The threshold contrast increase in Group 2 (0.070 +/- 0.035) was significantly higher than that in both Group 1 (0.043 +/- 0.040) and the control group (0.045 +/- 0.026) (p < 0.05 for both comparisons). There were no significant differences between Group 1 and the control group regarding log contrast sensitivity values with glare source and threshold contrast increase (p > 0.05 for both comparisons). CONCLUSIONS: The eyes with hydrophilic acrylic IOL showed better glare disability results than those with hydrophobic acrylic IOL. The superior performance of the hydrophilic acrylic IOL could be related to their lower refractive index and equi-convex design.

Acrylic Resins↗
PubMed1995

The safety and effectiveness of brain arteriovenous malformation embolization using acrylic and particles: the experiences of a single institution.

The purpose of this article is to report on the safety and effectiveness of brain arteriovenous malformation (AVM) embolization for two series of patients, of which one was treated with particulate embolization and the other with acrylic embolization. Sixty-five consecutive patients from embolization logs and patient records from 1988 to 1993 were reviewed. AVMs were routinely treated with particulate embolization early in the review (1988-1991), and after a transition period, the technique was changed to acrylic embolization for the remainder of the study period (1992-1993). All patients were treated with the ultimate goal of complete AVM obliteration. AVMs were embolized and resected, if possible, and if unresectable, they were reduced in size with embolization and radiated. The course of treatment for each patient was reviewed. The effectiveness at the end of treatment was analyzed for the ability to resect the AVM and, if unresectable, the ability to reduce the AVM to radiation size. Additionally, the safety of each embolization technique was evaluated in the context of comprehensive care, in terms of the safety of the procedure itself, the surgical resection after embolization, and the outcome at the end of comprehensive treatment. This article outlines the safety and effectiveness of acrylic and particulate embolization at a single institution. The ability to surgically resect an AVM after embolization and to reduce nidus size with acrylic was at least comparable with that with particulate embolization. Comprehensive complication rates were lower after acrylic embolization and were heavily influenced by a decreased number of surgical complications in the acrylic series. These data support the need to conduct a randomized prospective clinical trial to compare the relative safety and effectiveness of the two methods of embolization.

Acrylic Resins↗
PubMed2002

Effect of intrinsic pigmentation on the flexural strength of a microwave-cured acrylic resin.

This study investigated the effect of intrinsic pigmentation on the transverse strength of a microwave-cured acrylic resin. Forty transverse strength specimens were fabricated according to ADA specification #12 and divided into 5 groups. No fibers were added to group I (GI, control group); acrylic stain (AS) was added to GII and GIII in concentrations of 0.5 and 1.5% w/w, respectively; acrylic fibers (AF) were added to groups GIV and GV in concentrations of 0.5 and 1.5% w/w, respectively. All specimens were irradiated in a microwave oven with a cycle of 3 min at 360 W, followed by 4 min resting, then 3 min at 810 W. Flasks were bench-cooled for 30 min at room temperature, followed by immersion in cold tap water for 30 min. After storage in distilled water at 37 degrees C for 48 h, all specimens were tested for flexural strength in a testing machine (EMIC-DL 500) at a crosshead speed of 0.5 cm/min. Mean and standard deviation (MPa) for the flexural strength test were: GI = 86.0 +/- 7.9; GII = 86.0 +/- 9.8; GIII = 86.6 +/- 7.7; GIV = 84.9 +/- 5.3; GV = 84.9 +/- 5.2. No statistical differences were detected among the groups (ANOVA, p > 0.05). The addition of the acrylic fibers or the acrylic stain did not affect the transverse strength of the microwave-cured acrylic resin.

Acrylic Resins↗
PubMed2005

Effect of microwave treatments on dimensional accuracy of maxillary acrylic resin denture base.

Microwave energy has been used as an alternative method for disinfection and sterilization of dental prostheses. This study evaluated the influence of microwave treatment on dimensional accuracy along the posterior palatal border of maxillary acrylic resin denture bases processed by water-bath curing. Thirty maxillary acrylic bases (3-mm-thick) were made on cast models with Clássico acrylic resin using routine technique. After polymerization and cooling, the sets were deflasked and the bases were stored in water for 30 days. Thereafter, the specimens were assigned to 3 groups (n=10), as follows: group I (control) was not submitted to any disinfection cycle; group II was submitted to microwave disinfection for 3 min at 500 W; and in group III microwaving was done for 10 min at 604 W. The acrylic bases were fixed on their respective casts with instant adhesive (Super Bonder) and the base/cast sets were sectioned transversally in the posterior palatal zone. The existence of gaps between the casts and acrylic bases was assessed using a profile projector at 5 points. No statistically significant differences were observed between the control group and group II. However, group III differed statistically from the others (p<0.05). Treatment in microwave oven at 604 W for 10 min produced the greatest discrepancies in the adaptation of maxillary acrylic resin denture bases to the stone casts.

Acrylic Resins↗
PubMed2001

Comparison of the short-term clinical results of silicone and acrylic intraocular lens in patients with diabetes mellitus.

In order to compare the clinical results of silicone intraocular lenses (IOLs) and acrylic IOLs in patients with diabetes mellitus (DM), we reviewed the records of 69 diabetic patients (79 eyes--40 eyes; silicone IOLs, 39 eyes; acrylic IOLs) who had undergone phacoemulsifications and posterior chamber intraocular lens (PCI) implantations between January 1994 and January 1999. Postoperative ocular examinations included measurements of uncorrected and best corrected visual acuity tests and recording any complication one day, one week and two months after surgery. There was no statistically significant difference in visual acuity between the eyes with silicone IOLs and those with acrylic IOLs. Additionally, there was no difference in visual acuity according to the method of blood sugar level control. The rate of posterior capsular opacity (PCO) was significantly lower in the patients with acrylic IOLs than in those with silicone IOLs (p<0.05). These results suggest that there is no difference in visual outcome between acrylic IOLs and silicone IOLs in patients with DM. However in view of the lower rates of PCO with acrylic IOLs, they may be a better choice for eyes in diabetic patients.

Acrylic Resins↗
PubMed2006

Comparison of acrylic and polymethyl methacrylate lenses in a pediatric population.

PURPOSE: To compare the intra-patient incidence of posterior capsular opacification (PCO) and their post operative course, in children with bilateral cataract, following implantation of acrylic (Group 1) and polymethyl methacrylate (PMMA) (Group 2) intraocular lenses (IOLs). MATERIALS AND METHODS: This was a prospective, interventional intra-patient case series. Twenty-five children with bilateral cataract, 5 years and older, underwent cataract surgery and implantation of an acrylic (AcrySof MA30BA, Alcon, Fortworth, TX) in one eye and PMMA (Indo Am IAB 203, Ocular Vision, Inc.) IOL in the other eye of each patient. They were followed up for an average of 11.1 +/- 9.5 months to assess the incidence of clinically significant PCO and occurrence of postoperative complications. RESULTS: Twenty-three children (46 eyes), were included in this study. Post-operatively, 22(95.6%) patients with acrylic IOLs and 20 (86.9%) patients with PMMA IOLs, either maintained or improved their vision. In the acrylic and PMMA IOL groups respectively, the incidence of clinically significant PCO was 21% (4) and 75% (12) ( P =0.002), with a median onset at 2.9 months and 0.7 months. Other complications included pupillary capture in 2 (8.7%) eyes and uveal prolapse in 1 (4.3%) eye in the acrylic group and increased uveal inflammation in 6 (26.1%) eyes and presumed noninfectious endophthalmitis in 2 (8.7%) eyes in the PMMA group. CONCLUSION: Incidence of PCO and post operative uveal inflammation is significantly less with acrylic lenses and were safe to use in pediatric eyes.

Acrylic Resins↗
PubMed1999

Allergic contact dermatitis to acrylates in disposable blue diathermy pads.

We report 2 cases of elicitation of allergic contact dermatitis to acrylates from disposable blue diathermy pads used on patients who underwent routine surgery. Their reactions were severe, and took approximately 5 weeks to resolve. Both patients gave a prior history of finger tip dermatitis following the use of artificial sculptured acrylic nails, which is a common, but poorly reported, cause of acrylate allergy. Patch testing subsequently confirmed allergies to multiple acrylates present in both the conducting gel of disposable blue diathermy pads, and artificial sculptured acrylic nails. We advocate careful history taking prior to surgery to avoid unnecessary exposure to acrylates in patients already sensitized.

Acrylates↗
PubMedDate not supplied

Neodymium:YAG capsulotomy rates following phacoemulsification with implantation of PMMA, silicone, and acrylic intraocular lenses.

BACKGROUND AND OBJECTIVE: Posterior capsular opacification (PCO) is the most common visually disabling sequela of modern cataract surgery. Methods of reducing its incidence include the development of newer surgical techniques and intraocular lens (IOL) materials and designs. The aim of this study was to compare the incidence and time interval of development of PCO, and the requirement of laser capsulotomy in patients implanted with a polymethylmethacrylate (PMMA), silicone, or acrylic IOL. PATIENTS AND METHODS: The data of 340 consecutive patients who underwent phacoemulsification and implantation ofa PMMA, silicone, or acrylic intraocular lens were analyzed. The aim of this study was to compare the incidence and time interval of development of PCO, and the requirement of laser capsulotomy in patients implanted with a PMMA, silicone, or acrylic IOL. RESULTS: The incidence of PCO was found to be significantly less in the acrylic group (6.5% as compared to 21.74% and 26.6% in the PMMA and silicone groups, respectively; P = 0.01297 and 0.0039). Most patients (65%) exhibiting PCO in the PMMA group developed it within the first six months. In the silicone group, development of PCO was delayed. In 60% of patients, it appeared 18 months after surgery. Neodymium:YAG capsulotomy was required in 45% and 60% of patients developing PCO in the PMMA and silicone groups, respectively, while it was required in only 1 of the 4 patients developing PCO in the acrylic group. CONCLUSION: This study indicates that implantation of an acrylic IOL helps reduce the incidence of PCO as well as the need for Nd:YAG capsulotomy. PMMA IOLs require Nd:YAG capsulotomy earlier in the postoperative period as compared to silicone IOLs.

Acrylic Resins↗
PubMedDate not supplied

Chairside polishing of heat-cured acrylic resin: an SEM and EDA study.

PURPOSE: This study investigated the surfaces produced on two commonly used heat-cured acrylic resins by two chairside polishing systems compared to conventional lathe polishing. It used energy dispersive analysis (EDA) and scanning electron microscopy (SEM) to investigate the abrasive materials bonded in the silicone points that are marketed for chairside polishing of acrylic resin. MATERIALS AND METHODS: Using the three polishing systems (conventional as control, Shofu acrylic polishing system [AcryPoint], and Kenda Queen silicone polisher), three operators polished specimens using a defined protocol. Specimens were subjected to SEM and confocal microscopy. EDA was undertaken on the silicone polishing points. RESULTS: Conventional polishing produced the superior surface, followed by the surfaces produced by the Shofu system and then Kenda Queen. However, both chairside polishing systems produced smoother surfaces on acrylic resin than the surfaces produced by either steel or tungsten carbide burs. Both the Shofu acrylic polishing system and Kenda Queen silicone polisher contain beads of cerium, which is widely used in industry for polishing of glass. CONCLUSION: Silicone polishing points marketed for polishing of acrylic resin could be used to produce smooth surfaces that have been adjusted with burs where there is no access to a laboratory lathe.

Acrylic Resins↗
PubMed1991

[Effect of acrylate industry wastes on the environment and the prevention of their harmful action].

Acrylic and methacrylic++ acids and monomers as raw materials for production of polymers and copolymers are highly and extremely dangerous substances causing chronic intoxication. At low concentrations, acrylates and methacrylates++ have been found to produce not only systemic toxic, but embryotoxic effects. Manufacture of methacrylic++ and acrylic acids and monomers yields waste gases and waters that contain various acrylic compounds as impurities. The sewage treatment system introduced prevents the pollution of reservoirs with these compounds. High concentrations of acrylates and methacrylates are recorded in the sources of waste gases. It is required that fundamentally new waste--free technological processes for production of methacrylates++ and acrylates be designed and introduced and that the waste gas decontamination systems be improved in order to enhance the efficiency of measures to prevent environmental pollution.

Abortion, Spontaneous↗
PubMed1989

Effect of environmental temperature and humidity on bonding of acrylic resin to enamel.

The bond strength of acrylic resin to enamel is easily affected by moisture, temperature, etc. It is especially true that if there is water on the enamel surface, the bond strength declines drastically. In cases of orthodontic treatment which required bonding of many brackets at once we cannot practice perfect dry field techniques such as with a rubber dam. Accordingly the bond strength of acrylic resin under varying environmental conditions temperature and humidity was measured. The results were as follows; 1) The bond strength of acrylic resin to non-etched enamel was effected by temperature and humidity rather than by liquid/powder ratio. 2) The bond strength of acrylic resin to non-etched enamel declined with an increase in temperature at the same humidity. 3) The bond strength of acrylic resin to etched enamel was effected by the liquid/powder ratio, rather than by humidity when compared with non-etched enamel cases. 4) The bond strength of acrylic resin to etched enamel was not affected by temperature or humidity at a certain liquid/powder ratio. 5) There was no significant difference of formation of resin tags between the liquid/-powder ratio at low temperature and low humidity. Formation of resin tags at high humidity had sharp appearance in proportion to the low liquid/powder ratio.

Acid Etching, Dental↗
PubMed1997

Collagen-coated acrylic microspheres for embolotherapy: in vivo and in vitro characteristics.

PURPOSE: To evaluate the in vivo and in vitro properties of collagen-coated acrylic microspheres and to compare them with polyvinyl alcohol (PVA) particles. METHODS: Samples of 100- to 300-microns, 300- to 500-microns, 500- to 700-microns, and 700- to 900-microns collagen-coated acrylic microspheres and 200- to 300-microns PVA particles were suspended in solutions of 50% saline and 50% contrast material. The samples were evaluated for quantitative and qualitative microscopic characteristics (shape, size, deformability); injectability via standardized microcatheters; degree of particulate penetration in the pig rete mirabile; and reaction of tissue to the particles in 48-hour- and 4-week-old specimens. RESULTS: The acrylic microspheres were spherical and deformable. The sample of 100- to 300-microns microspheres (n = 202) had a mean diameter of 210 microns (standard deviation, 43 microns). Hub accumulation, particle aggregation, and catheter occlusion were not observed with the microspheres (all sizes) but were noted with the PVA particles. The 200- to 300-microns PVA particles formed aggregates in the proximal rete. The 100- to 300-microns microspheres were found throughout the rete and beyond. Chronic transmural and perivascular inflammation was observed with the microspheres and the PVA particles. CONCLUSIONS: Particle aggregation and catheter occlusion do not complicate the transcatheter delivery of collagen-coated acrylic microspheres as they do with PVA particles. For a given particle and vessel size, acrylic microspheres penetrate to a much greater extent than the PVA particles. Tissue reaction to acrylic microspheres and PVA particles is similar.

Acrylic Resins↗
PubMed1998

Contact leukoderma caused by patch testing with dental acrylics.

Several chemicals are capable of inducing contact leukoderma. Here we report on a dental nurse who had been investigated elsewhere at a dermatology clinic 2.8 years earlier because of suspected occupational fingertip dermatitis. She had been patch tested on her upper arm with dental acrylic resins "as is." These strong concentrations of patch test substances caused a severe allergic reaction in the upper arm, and the patch test sites have remained vitiliginous for 2.8 years. Active sensitization did not take place because the patient had been sensitized earlier as shown by the allergic 2-day readings with acrylics during the first patch test session. It is assumed that acrylates induced contact vitiligo, but the dental acrylics may have also contained other chemicals (eg, hydroquinone or phenolic substances) capable of causing vitiligo. The main point to be learned from the present results is that dental acrylics should never be patch tested "as is." We also discourage the practice of use tests, open tests, or repeated open patch tests with undiluted dental acrylics because of the risk of active sensitization from single exposure.

Acrylic Resins↗
PubMed1987

Biodegradable microspheres. X: Some properties of polyacryl starch microparticles prepared from acrylic acid-esterified starch.

Acrylic acid-esterified starch was produced by reacting starch with acrylic acid chloride. This reaction was rapid and easy to control. Introduction of acrylic groups into starch reduced the enzymatic degradability of starch (e.g., with 12 acrylic groups/100 glucose residues, approximately 75% of the degradation products eluted before glucose on gel filtration). The degradability could be increased to a large extent by preincubation at pH 5.5 in vitro (e.g., after 16 weeks, the corresponding figure was approximately 15%). The acrylic acid-esterified starch was used to prepare polyacryl starch microparticles. These were rapidly eliminated from the circulation after iv injection in mice, mainly by uptake in the liver. The elimination of the microparticles from the liver, monitored with [14C]starch, displayed a half-life of approximately 3.5-4.5 months. After 5 and 6 months, approximately 30% of the initial radioactivity remained in the liver. This is equivalent to the amount anticipated from the enzymatic degradation of the monomer (acrylic acid-esterified starch) in vitro and the innate nondegradability of the 14C-marker. These results, taken together, indicate that the ester bond between starch and the hydrocarbon chain in polyacryl starch microparticles is hydrolyzed at lysosomal pH.

Animals↗
PubMed1996

Differential Metabolism of Dimethylsulfoniopropionate and Acrylate in Saline and Brackish Intertidal Sediments

In anoxic Spartina alterniflora-dominated sediments along a naturally occuring salinity gradient (the Cooper River estuary, South Carolina, U.S.A.), dimethylsulfoniopropionate (DMSP) was metabolized to dimethyl sulfide (DMS) and acrylate by sediment microbes. The rate of DMSP degradation and acrylate mineralization by sediment microbes was similar at all sites along this 25-km transect. However, sediments amended with acrylate (or DMSP) showed significantly higher rates of N2 fixation (measured as acetylene reduction activity) (ARA) in the saline sediments downstream than brackish sediments. These results are consistent with the fact that acrylate stimulated the rates of both denitrification and CO2 production in the saline sediments at the mouth of the river more than tenfold over rates in brackish sediments. Enrichment experiments indicate that microbes capable of using DMSP or acrylate were not present in upstream sediments despite the fact that microbial biomass, percent organic matter, and both glucose-stimulated ARA and denitrification were highest upstream. It appears that acrylate utilizing, N2 fixing, and denitrifying populations are insignificant in the lower salinity sediments of the estuary. These results may reflect the availability of DMSP, which averaged 10.3 nmol g wet wt-1 of saline sediments and levels less than our detection limit (1 &mgr;M) in brackish sediments.

Journal Article↗