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PubMed2003

[Percutaneous transpedicular acrylate vertebroplasty for the treatment of lumbar vertebral hemangioma--case report].

The authors present the management of a patient suffering from lumbar vertebral hemangioma. Percutaneous transpedicular acrylate vertebroplasty was performed. This method has widely been used for the treatment of pathological vertebral bodies of different aetiology. A brief review of the literature of previous and current methods is presented. A detailed discussion is given why vertebroplasty was used in contrast to the radiological investigation where the patient's hemangioma proved to be a non-aggressive type. According to the authors' knowledge this is the first Hungarian publication of acrylate vertebroplasty for the treatment of vertebral hemangioma.

Acrylates↗

PubMedDate not supplied

Opacification of two hydrophilic acrylic intraocular lenses 3 months after implantation.

BACKGROUND AND OBJECTIVE: To report clinical, pathologic, histochemical, ultrastructural, and spectrographic analyses of explanted hydrophilic acrylic intraocular lenses (IOLs) obtained from two patients who had early visual disturbances caused by postoperative opacification of the lens optic. MATERIALS AND METHODS: Two hydrophilic IOLs were explanted from patients with decreased visual acuity. The patients became symptomatic 3 months after uneventful phacoemulsification and lens implantation. IOL optic opacification was associated with a fine granularity within the substance of the lens optic. The IOLs were examined by gross and light microscopy. Full-thickness cut sections of the optics were stained with 1% alizarin red (a special stain for calcium). Some sections were submitted for scanning electron microscopy and energy dispersive x-ray spectroscopy. RESULTS: Microscopic analyses revealed the presence of multiple fine, granular deposits of variable sizes within the optics of the lenses distributed in a line parallel to the anterior and posterior curvatures of the optic, with a clear zone just beneath the optics' surface. Extension of the opacification into the haptics of the IOLs could also be observed. The deposits stained positive with alizarin red. Energy dispersive x-ray spectroscopy of the internal substance of the IOLs also demonstrated the presence of calcium within the deposits. CONCLUSIONS: This is the first clinicopathologic report of optic and haptic opacification occurring with this hydrophilic acrylic IOL model only 3 months postoperatively. Further studies on other similar cases with this lens should be done to determine the incidence and possible mechanisms of this phenomenon.

Acrylic Resins↗

PubMed2003

[Effects of removable plate dentures made of acrylic plastic on the structure and function of oral mucosal cell membranes].

The results of orthodontic treatment of 120 patients with complete and partial adentia are presented. The patients were fitted with removable plate dentures on the base of acrylic polymers trevalon, fluorax, ethacryl, and redont. The results of biochemical and morphological studies recommend the basic material trevalon for practical orthodontics. Measurements of medium molecular weight oligopeptides, histamine, malonic dialdehyde, and activities of antioxidant enzymes are recommended for predicting the time and quality of patients' adaptation to removable plate dentures from acrylic polymers.

Acrylates↗

PubMedDate not supplied

[External fixation with autopolymerizing acrylic resin].

In November 1970, a new method of skeletal fixation was devised using self-curing acrylic resin. Manipulative reduction of the displaced fracture is made using screws inserted into the bone fragments under an image intensifier. After reduction, the proximal and distal fragments are joined together with the aid of self-curing acrylic resin. Adjacent joints can be exercised immediately after operation and the fixation is so firm that the use of a plaster cast after operation is not necessary. This simple method can be used in osteosynthesis, compression arthrodesis and various types of osteotomy.

Acrylic Resins↗

PubMed2003

Bonding of silicone extra-oral elastomers to acrylic resin: the effect of primer composition.

Silicone elastomer is bonded to acrylic resin in many facial or oro-facial prostheses. The silicone elastomer/acrylic resin bond has been reported to be insufficient and primers have been used to enhance the bond. This study investigated the bond strength of silicone elastomer to acrylic resin using different types of primers. The extra-oral silicone elastomers studied were Cosmesil and Ideal. The "overlap-joint" model was used to evaluate the bond strength and the samples were stretched until fracture. The bonding surfaces were treated with a primer. The control primer was Cosmesil and the others a mixture of Cosmesil/Z-6020 and Cosmesil/A-174 in 50/50 v/v ratio. The bond strength ranged from 0.026 MPa to 0.219 MPa. The results obtained in this work led to the conclusion that the most critical parameter allowing the efficient performance of a primer is the compatibility and affinity of its composition with the selected silicone elastomer.

Acrylic Resins↗

PubMed2003

Comparison of bond strengths between adhesive and conventional acrylic resins to cobalt chromium denture base alloy.

In removable partial dentures there is normally no chemical bonding between the cast alloy and the poly(methylemethacrylate). Mechanical retention of the resin to the casting is required and presents a significant challenge during the design of partial dentures. Recently developed adhesive denture base resins which contain the monomer 4-methacryloxyethyl trimellitate anhydride can create a chemical bond to partial denture alloys. This study investigated the bond strength of adhesive denture base resin (Metafast) and conventional acrylic resin (Croform x 10) to partial denture alloy (CoCr) under three different storage conditions (dry, water, water with thermocycling). The results showed that the bond strength of the conventional acrylic resin (Croform x 10) was less than the bond strength of the adhesive denture base resin (Metafast) and the storage environment had a significant effect upon the bond strength of both resins.

Acrylic Resins↗

PubMed2003

Dimensional changes and water sorption of two acrylic polymer materials reinforced with glass fibres.

The purpose of this study was to examine the effect of glass fibre reinforcement on the dimensional changes and water sorption of a heat-polymerising denture acrylic polymer and a microwave-polymerising denture acrylic polymer. Fifteen specimens from each group were prepared with 2% by weight (18 mg) E-glass fibre and 15 without glass fibre. The dimensional change measurements were made at three different stages on the 60 specimens. The water sorption calculations were made on specimens immersed in distilled water at 37 degrees C +/- 1 degree C for 0, 1 and 7 days. Glass fibre reinforcement and processing method do not affect the dimensional change of test specimens, but as the time increased the dimensional change decreased. The glass fibre reinforcement decreased water sorption, but the two processing methods failed to show a significant difference.

Absorption↗

PubMedDate not supplied

Influence of storage conditions and type of plasticizers on ethylcellulose and acrylate films formed from aqueous dispersions.

PURPOSE: To investigate the influence of storage conditions and types of plasticizers on the properties and stability of ethylcellulose and polymethacrylate films and to elucidate the mechanism for the changes observed. METHODS: Films were prepared from Surelease, Aquacoat and Eudragit L 30D dispersions by the casting method. The effects of different plasticizers on the morphology, transparency, mechanical property and water vapour permeability of the prepared films were studied. The film samples were exposed to storage conditions of 30 degrees C and 50 or 75 %RH. Samples were removed at pre-determined time intervals for mechanical testing and analysis of plasticizer content in the films. RESULTS: It was found that films prepared from aqueous ethylcellulose dispersions were relatively weaker and more brittle than acrylate films. Acrylate films did not show any significant change in mechanical property when stored at high humidity. However, the properties of ethylcellulose films stored at high humidity varied depending on the type of plasticizers present. CONCLUSIONS: The changes in mechanical property of ethylcellulose films on storage were mainly attributed to the loss of plasticizers during storage, causing further coalescence of ethylcellulose films and to a smaller extent, reduction in moisture content of the film.

Acrylates↗

PubMed2003

[Acrylic IOL implantation with the Monarch II injector].

PURPOSE: To study the technical difficulties using the MONARCH II injector, intraoperative incidents, postoperative astigmatism. METHODS: Retrospective study which included 135 eyes with cataract who underwent cataract surgery between March 2002-August 2003. The surgical intervention consisted of lens extraction by phacoemulsification technique and IOL implantation with the MONARCH II injector. We recorded the following parameters: problems during the loading of the IOL in the cartridge, difficulties during the implant, problems due to the damage of the IOL during the passage in the cartridge, IOL centration in the capsular bag, induced postoperative astigmatism. RESULTS: We had no major difficulties using this type of injector. We did not recorded important differences between the hydrophobic and hydrophilic IOLs. We had a number of 17 intraoperative incidents (12.6%). We met the following intraoperative incidents: the last haptic capture in the tunnel of the cartridge in 5 cases (3.7%), small marks on the optic surface left by the tip of the injector in 3 cases (2.2%), the leading haptic stuck on the optic surface in 2 cases (1.4%), breaking of the last haptic (multi-piece IOL) in 1 case (0.7%), the turning up side down of IOL during unfolding (hydrophilic IOLs) in 6 cases (4.4%). Postoperative astigmatism was less than 1D cylinder in 88% of cases. CONCLUSIONS: The IOL implantation using MONARCH II injector is easy and doesn't need learning curve. The technique is superior compared with forceps implantation (especially for acrylic hydrophilic IOLs). No significant differences between implantation of acrylic IOLs. IOL centration was good. The design of the injector tip preserved optic surface and haptic from damage. The conical tip of the cartridge didn't change the architecture of the corneal wound. The postoperative astigmatism was small.

Acrylic Resins↗

PubMed2004

[Comparison of surface light scattering of acrylic intraocular lenses made by lathe-cutting and cast-molding methods--long-term observation and experimental study].

PURPOSE: To compare the long-term clinical and experimental results of soft acrylic intraocular lenses(IOLs) manufactured by the lathe-cut(LC) method and by the cast-molding(CM) method. METHODS: This was a retrospective study of 20 patients(22 eyes) who were examined in a 5- and 7-year follow-up study. Sixteen eyes were implanted with polyacrylic IOLs manufactured by the LC method and 6 eyes were implanted with polyacrylic IOLs manufactured by the CM method. Postoperative measurements included best corrected visual acuity, contrast sensitivity, biomicroscopic examination, and Scheimpflug slit-lamp images to evaluate surface light scattering. Scanning electron microscopy and three-dimensional surface analysis were conducted. RESULTS: At 7 years, the mean visual acuity was 1.08 +/- 0.24 (mean +/- standard deviation) in the LC group and 1.22 +/- 0.27 in the CM group. Surface light-seatter was 12.0 +/- 4.0 computer compatible tapes(CCT) in the LC group and 37.4 +/- 5.4 CCT in the CM group. Mean surface roughness was 0.70 +/- 0.07 nm in the LC group and 6.16 +/- 0.97 nm in the CM group. CONCLUSION: Acrylic IOLs manufactured by the LC method are more stable in long-termuse.

Acrylic Resins↗

PubMed2004

Study of a three-stage fluidized bed process treating acrylic synthetic-fiber manufacturing wastewater containing high-strength nitrogenous compounds.

Polyacrylonitrile (PAN) is one of the major synthetic fibers commonly used in the mass production of clothing. The chemical synthesis of PAN is carried out by polymerization of the acrylonitrile (AN) monomers with co-monomers such as vinyl acetate, methyl acrylate and cyclohexyl acrylate. Using water quality analysis of the PAN wastewater, high concentration of organic nitrogen was found and the TKN/COD ratios achieved were 0.15-0.26, indicating the complicated biodegradation characteristics for the PAN wastewater. In order to enhance biodegradation of nitrogenous compounds in PAN wastewater, a combined three-stage process of thermophilic anaerobic/anoxic denitrification/aerobic nitrification fluidized bed reactors was employed. The results indicated that the concentration of effluent in the three-stage process of OD and organic nitrogen was 175 mg/L and 13 mg/L, respectively. Furthermore, molecular biotechnology was applied to study the microbial population in the thermophilic anaerobic fluidized bed reactor. From the results of denaturing gradient gel electrophoresis, the diversity of PAN-degrading bacteria would change in different volumetric loading. Furthermore, the bacteria communities in the thermophilic anaerobic fluidized bed reactor were also studied by fluorescence in situ hybridization and confocal laser scanning microscopy. Alpha and delta-Proteobacteria were dominant in the bacteria population, and some high G+C content bacteria and Clostridium could be characterized in this system.

Acrylic Resins↗

PubMed2004

[Acrylates as a significant source of occupational and non-occupational contact allergy].

The authors review the literature on the contact allergy to acrylate plastics used in many branches of industry, construction, dental prosthetics, conservative dentistry, orthopedics and also in the production of glue, binding materials, and lacquers, especially printer's ink. The most frequent sources of non-occupational allergy are presented. In addition, the authors draw attention to new allergy-producing chemical compounds, difficulties in the interpretation of skin test results, mostly because of polyvalence of allergy to acrylates, and to characteristic clinical picture of skin changes.

Acrylates↗

PubMed2005

Patients' preference for acrylic resin major connector analogues formulated for titanium alloy removable partial dentures.

PURPOSE: Aim of this study was to determine patients' preference to acrylic resin major connector analogues (MCA) that simulated strengthened major connector designs formulated for Ti-6Al-7Nb alloy. MATERIALS AND METHODS: Four MCA namely wide design (Wide), design with 2 strengthening ridges (2SR), design with 1 strengthening ridge (1SR), and thick design (Thick) were fabricated using light-polymerizing acrylic resin for 10 patients with Kennedy Class I or II partially edentulous maxillary arches. They were asked to wear each MCA in the mouth for 30 seconds in 6 pairs, and to report their preference for each pair. Using these data the 4 MCA were ranked in a descending preference order for each patient. A within-subject comparison of preferences was performed with the Friedman test and multiple comparisons with Wilcoxon Signed Ranks test. RESULTS: A statistically significant preference order was revealed: Wide, 1SR, 2SR, and Thick (P < 0.008). The wide design (P < 0.004) and the 1SR (P < 0.01) were significantly preferred to the thick design. However, individual data showed that the first preference varied depending upon the subject. CONCLUSION: Thinner designs tended to be preferred to the thicker design by the subjects, while none of the designs tested were consistently selected as the best design.

Acrylic Resins↗

PubMed2005

Physical properties of four acrylic denture base resins.

Resistance to impact fracture and high flexural strength are desirable properties of denture base acrylics. The purpose of this laboratory study was to determine the Izod impact strength, the flexural strength, the flexural modulus, and the yield distance for four premium denture resins. Bar specimens 86 x 11 x 3 mm of Lucitone 199, Fricke Hi-I, ProBase Hot, and Sledgehammer Maxipack were fabricated following the manufacturer's instructions for heat processing. The bars were surface finished using silicon carbide paper to 600 grit. Ten specimens from three lots of each material were made (n=30). Flexural strength, flexural modulus, and yield distance were determined by testing the specimens to failure using a three-point test fixture. Izod impact strength was determined using an Izod tester on un-notched specimens generated from the flexural test (n=60). Analysis of variance (ANOVA) and post-hoc Tukey's test were used for statistical comparison of each property. There were significant differences in the physical properties among the denture acrylics tested. Lucitone 199 demonstrated the highest impact strength, flexural strength, and yield distance (p<0.05). Lucitone 199 with an Izod impact strength of 5.5+/-1.2 N'm, a flexural strength of 99.5+/-4.5 MPa, and yield distance of 9.9+/-0.76 mm exhibited statistically greater results than Fricki Hi-I, ProBase Hot, and Sledgehammer Maxipack. Fricki Hi-I with a yield distance of 7.3+/-1.1 mm was statically greater than ProBase Hot and Sledgehammer Maxipack. Fricki Hi-I, ProBase Hot, and Sledgehammer Maxipack were statistically similar for the Izod impact strength and flexural strength tests performed. ProBase Hot and Sledgehammer Maxipack yielded statistically similar results for all tests performed. Flexural modulus had an inverse relationship to the impact strength, flexural strength, and yield distance.

Acrylic Resins↗

PubMed2006

Effect of five staining solutions on the colour stability of two acrylics and three composite resins based provisional restorations.

The effect of coffee, tea, coca-cola, orange-juice and red wine on the colour stability of acrylic and composite based provisional materials were evaluated. Two acrylic resins and three composite resins were studied. 48 standardized specimens for each provisional material were prepared. Each group was divided into 6 subgroups. Specimens from each group were immersed in staining solutions at room temperature for 30 days. Red wine and tea caused the most significant colour changes and orange juice showed the least significant colour changes. deltaE of all of the provisional restorations materials was changed after the immersion in all of the staining solutions during the experimental process.

Acrylic Resins↗

PubMed2006

[Sulcus fixation of a foldable acrylic intraocular lens].

AIM: To describe a surgical technique for sulcus fixation of a foldable single-piece acrylic intraocular lens (IOL) through a 3.0 mm clear cornea incision. PATIENTS AND METHODS: Between 2003 and 2004, this technique was used in 10 eyes at Sestre Milosrdnice University Hospital. Seven eyes were aphakic secondary to a capsule defect during phacoemulsification, one eye had a perforating injury with lens destruction, and two eyes were aphakic after congenital cataract extraction in childhood. In all eyes an AcrySof Natural SN60AT foldable single-piece acrylic IOL (Alcon, Forth Worth, TX, USA) was implanted. RESULTS: The median age of patients at surgery was 41 (range 31-68) years, and the median follow up was 11 (range 4-18) months. In all cases, the intraocular lens was placed and fixed in the anatomic sulcus without complications. Slight IOL decentration (up to 1.0 mm) was seen in 2 eyes, and transient hypotonia and transient cystoid macular edema in 1 eye each. DISCUSSION: In the absence of adequate posterior capsule support, scleral sutured posterior chamber intraocular lens implantation has become a popular technique. The reduction in incision, from 7 mm for the implantation of poly(methyl methacrylate) (PMMA) IOL to 3 mm for foldable IOL, represents an improvement in the technique, allowing for good postoperative vision recovery. Small incision helps maintain adequate intraoperative intraocular pressure in the anterior chamber. The design of single-piece AcrySof Natural lens allows for easy and safe fixation of the Prolene suture to the IOL. Also, this technique with scleral flaps that protects the exposed suture helps reduce the risk of endophthalmitis. Longer follow up is needed to ascertain the stability of this suture fixed IOL. CONCLUSION: Sulcus fixation of a foldable IOL offers an acceptable alternative for rehabilitation of vision function. The unique design characteristics of the single-piece AcrySof Natural IOL make possible the suture fixation through a small clear corneal incision.

Acrylic Resins↗

PubMed2006

Effect of five staining solutions on the colour stability of two acrylics and three composite resins based provisional restorations.

Acrylic Resins↗

PubMedDate not supplied

Reinforcing effect of a Ni-Cr alloy plate on an acrylic resin denture base.

The authors previously reported on the strengthening effect of a thin Ni-Cr plate on an acrylic resin test specimen in the three-point bending test. This study evaluated the reinforcement of acrylic resin denture bases by measuring the strain distribution in the palate of a maxillary complete denture. It was found that this reinforcing technique led to a uniform distribution of strain in the palatal area of the maxillary denture and a reduction of strain in the midpalatal area.

Acrylic Resins↗