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PubMed1975

Circulatory depression in bone after acrylic implantation.

Because of the continuing hazard of post-operative sepsis in joint replacement surgery and the possibility that persistent bone ischemia may be a contributing factor, it is desirable to know the hemodynamic consequences in bone of the implantation of orthopedic acrylic cement. Experiments were carried out on 60 rats. In 30, a bore-hole was made, unilaterally, in the tibia. In another 30, a bore-hole was made in the tibia and a small amount of polymethylmethacrylate cement (Surgical Simplex P) was implanted into the marrow cavity through the bore-hole. By means of 51-Cr labeled red cells and 59-Fe labeled resin particles, the blood volume and blood flow rate in the tibiae were calculated simultaneously as a percentage of the values in the contralateral tibiae. The results showed that at 14 days and 112 days postoperatively, both blood volume and flow were significantly depressed in tibiae in which acrylic cement had been implanted, as compared with tibiae in which only a bore-hole had been made. It was concluded that orthopedic cement implanted into bone renders the bone hypovascular.

Animals↗
PubMed2003

Limited uterine artery embolization with tris-acryl gelatin microspheres for uterine fibroids.

PURPOSE: To evaluate the midterm results of limited embolization of the uterine arteries in the management of symptomatic uterine fibroids and to evaluate the efficacy and safety of limited uterine artery embolization (UAE) with use of calibrated tris-acryl gelatin microspheres in the management of symptomatic uterine fibroids. MATERIALS AND METHODS: Twenty women (mean age, 43 years) with symptomatic uterine fibroids underwent bilateral embolization of the uterine arteries with use of calibrated microspheres. Devascularization of the fibroids was achieved and the main uterine artery was left patent in all women. Embolization was offered as an alternative to surgery in all women who had been treated unsuccessfully with medical therapy. RESULTS: All procedures were technically successful. Microspheres 700-900 micro m in diameter were used in 14 women (70%). After a mean follow-up duration of 30.2 months (range, 24-48 mo), all women reported improvement in their symptoms, with 85% reporting complete resolution of menorrhagia at the most recent follow-up. One woman with multiple fibroids required a second embolization procedure because of persisting symptoms at 6 months. She is currently symptom-free after 48 months. In two women with submucosal fibroids, expulsion of necrotic fibroids occurred 2 and 7 months after the procedure, respectively. All women resumed normal menstruation after the procedure. One woman had a successful full-term pregnancy after embolization. CONCLUSION: Early experience with UAE with use of calibrated tris-acryl gelatin microspheres indicates that it is safe and efficacious in controlling menorrhagia.

Adult↗
PubMed2003

Relative rates of blood flow reduction during transcatheter arterial embolization with tris-acryl gelatin microspheres or polyvinyl alcohol: quantitative comparison in a swine model.

PURPOSE: To determine whether two commonly used embolic agents have differing rates of blood flow reduction during transcatheter embolization of the renal arteries in an animal model. MATERIALS AND METHODS: The renal arteries of 10 pigs were embolized with either polyvinyl alcohol (300-500 or 500-700- micro m) or tris-acryl gelatin microspheres (300-500 or 700-900- micro m). Equivalent unit doses of each agent were suspended in 40 mL of fluid and injected in 1-mL aliquots for 20 mL and then in 5-mL aliquots for 20 mL. Blood flow was measured after each aliquot with an intraarterial Doppler flow wire placed through the embolization catheter. RESULTS: Renal arterial blood flow was most rapidly and reliably decreased by 300-500- and 700-900- micro m microspheres, both of which had achieved >90% reduction from baseline flow after the injection of 6 mL of suspension. An equivalent reduction in flow required 25 mL of 300-500- micro m PVA suspension and 30 mL of 500-700- micro m PVA suspension. The reduction in blood flow with microspheres was significantly greater (P <.05) than that with PVA between 5 and 19 mL of suspension delivered. Differences between larger and smaller particle sizes of the same agent were not statistically significant. CONCLUSIONS: Tris-acryl gelatin microspheres reduced renal blood flow more quickly and reliably than did PVA. The type of agent used in embolization had a greater impact on the rate of flow reduction than did particle size in the range of sizes tested.

Angiography, Digital Subtraction↗
PubMed1987

Microbial film formation: dental plaque deposition on acrylic tiles using continuous culture techniques.

A chemostat system has been developed to model the attachment of oral bacteria, and the subsequent development of plaque film, to acrylic surfaces immersed in steady state cultures. Plaque was removed from the teeth and gingival margin of volunteers who refrained from oral hygiene for at least 72 h. Samples were pooled and inoculated into a complex growth medium maintained at 37 degrees C. Glucose-limited continuous culture was established at a dilution rate of 0.05/h and at pH 7.0. Microbiological analysis of the culture indicated that a complex community of oral bacteria was established, typical of that found in dental plaque. Acrylic tiles were immersed in the fermenter through a modified fermenter head and incubated therein for up to 21 d. Scanning electron microscopy showed that either side of the tiles contained a rough and a smooth surface and these initially favoured the attachment of fusiform bacteria, particularly on the rough surface. Cocci attached to those surfaces which were not heavily colonized by the fusiforms and eventually grew into and on the colonial sheets of the fusiforms.

Adult↗
PubMed1987

The effect of sucrose on the colonization of acrylic by Candida albicans in pure and mixed culture in an artificial mouth.

The roles of sucrose and microbial interactions in the colonization of acrylic by Candida albicans in an artificial mouth were investigated. The acrylic was colonized by pure cultures of the organism but a visible plaque was not produced whether or not sucrose was present. Salivary bacteria had no effect in the absence of sucrose but when sucrose was present the numbers of C. albicans were significantly increased. It is suggested that this phenomenon is related to the production of extracellular polysaccharides by salivary streptococci in the presence of sucrose. In mixed culture of C. albicans and Streptococcus salivarius CJ2, growth of the latter was inhibited in the presence of sucrose. This inhibition was due to factors other than pH, although no such antagonism could be demonstrated on solid media.

Candida albicans↗
PubMed1987

The early bacterial colonization of acrylic palates in man.

Adhesive tape applied to the fitting surface was used to study the early colonization of acrylic palates in six subjects. Streptococci were major constituents of the plaque accumulated on the tape over the first 3 days. Bacterial colonization of the tape discs was selective in that dextran-producing streptococci constituted a greater proportion of the total streptococcal count after 15 min compared with that of the initial sample and saliva, while the converse was true for Streptococcus salivarius. Scanning electron microscopy showed that denture plaque development started in grooves and depressions on the surface of the tape, and became more extensive with time. Comparison of the colonization of tape and acrylic discs in one individual demonstrated that the tape was a suitable model for in vivo colonization of dentures or orthodontic appliances.

Adhesives↗
PubMed1992

Occupational pharyngitis associated with allergic patch test reactions from acrylics.

A female dentist specialized in orthodontics repeatedly developed symptoms of pharyngitis at work. A chamber provocation test indicated that her symptoms were caused by acrylics. Prick tests with acrylics were negative, while patch tests were strongly positive although the patient had no skin symptoms. The relationship between the symptoms and the patch test results is discussed. It is suggested that type IV allergic reactions may be involved in symptoms of the upper respiratory tract.

Bronchial Provocation Tests↗
PubMed1994

Development of a radiopaque, autopolymerizing dental acrylic resin.

PURPOSE: Current prosthetic acrylic resins are radiolucent and cannot be imaged using standard radiographic techniques. If accidentally impacted or ingested, delays in localizing or removing the foreign body may be life-threatening. The purpose of this study was to evaluate the influence of an experimental radiopaque additive, triphenyl bismuth (TPB), on polymethyl methacrylate resins formulated for dental use. We also investigated methods to improve TPB-containing resin microbeads and optimize processing variables for specimen fabrication in autopolymerizing resin systems. MATERIALS AND METHODS: Selfcured samples of experimental resins were prepared containing 0% to 27% TPB and were tested according to American National Standards Institute/American Dental Association and International Organization for Standardization performance standards. A control group and two commercial provisional crown and bridge resins were used for comparison. RESULTS: The standard of radiopacity (> or = aluminum radiopacity) is met at TPB levels of > or = 14.5%. The control resin had a greater transverse deflection compared with the TPB-resin groups, but deflection was within standard limits for all resins. Polishability, color stability, and solubility were unaffected by TPB, whereas sorption decreased, although not significantly, at higher TPB levels. Translucency decreased at 27% TPB, and specimens containing 0% to 20% TPB were transparent. A tendency to entrain air bubbles, because of the hydrophobicity of TPB, resulted in increased susceptibility to brittle failure at the higher TPB levels. Solubility slightly exceeded American Dental Association standards for all TPB-resins and the control. All other performance standards were acceptable for resins containing 0% to 20% TPB. CONCLUSIONS: At concentrations that provide a diagnostic level of radiopacity, TPB does not significantly alter required performance and processing properties. Thus, TPB is capable of commercially acceptable performance as a radiopacifying additive for dental acrylics.

Analysis of Variance↗
PubMed1996

Comparison of the in vitro fatigue resistance of an acrylic resin removable partial denture reinforced with continuous glass fibers or metal wires.

PURPOSE: The fatigue resistance of heat-polymerized acrylic resin test specimens reinforced with continuous glass fibers or metal wire was investigated. MATERIALS AND METHODS: Test specimens in the shape of maxillary removable partial dentures were reinforced with one of the following: (1) circular steel wire (cross-sectional diameter, 1.0 mm); (2) semicircular steel wire (cross-sectional diameter, 1.0 x 2.0 mm); or (3) continuous unidirectional E-glass fibers. Ten specimens were fabricated for each test group. The specimens were tested by a constant force flexural fatigue test at a force of 180 N while immersed in 37 degrees C water. The number of loading cycles required to generate a fatigue fracture and the position of the fracture were measured. RESULTS: Results showed that the test specimens, which were either unreinforced or reinforced with metal wires, fractured after 13,197 to 39,237 loading cycles. For the glass fiber-reinforced test specimens, the fracture did not coincide with the region of the strengthener but with the opposite side of the test specimen after 1,239,298 loading cycles. The position of the fracture showed a statistically significant variation between the test groups (P < .001). CONCLUSIONS: This study suggests that the fatigue resistance of acrylic resin removable partial dentures reinforced with glass fibers are superior to those removable partial dentures reinforced with conventional metal wire.

Analysis of Variance↗
PubMed1995

Visualization of C7-T1 on portable lateral cervical spine radiographs using a lead-lined acrylic filter.

OBJECTIVE: To determine whether lead-lined acrylic cervical filters can improve the quality of portable lateral cervical spine (c-spine) radiographs for trauma patients. METHODS: Twenty trauma patients who required portable c-spine x-rays had these taken with a lead filter attached to the collimator of the portable x-ray machine to improve penetration and visualization of lower cervical structures without overpenetrating upper cervical structures. The radiographs of these patients were compared with the first portable c-spine radiographs without filters for 20 controls matched for gender and injury severity. The comparison of radiographs was done by an experienced emergency physician and a neuroradiologist blinded to whether the filter was used. RESULTS: The two groups were similar for demographic and clinical characteristics. There was a significant improvement in the ability to visualize the C7-T1 level for the filter group compared with the control group (65% vs 30%, p < 0.05). Agreement between the physicians was excellent (kappa = 0.79, 95% CI = 0.60-0.99). CONCLUSIONS: Lead-lined acrylic filters improve the ability to visualize the lower c-spine in trauma patients.

Adult↗
PubMed2006

High-performance liquid chromatography-ultraviolet-visible spectroscopy-electrospray ionization mass spectrometry method for acrylic and polyester forensic fiber dye analysis.

A critical point of comparison between a fiber collected from a crime scene and a fiber from a known source is the color. Fiber dye analysis using thin-layer chromatography or ultraviolet (UV)-visible (Vis) microspectrophotometry provides useful, although limited, data for comparison. High-performance liquid chromatography-electrospray ionization mass spectrometry (LC/MS) overcomes these limitations by integrating chromatography, ultraviolet-visible spectroscopy, and mass spectrometry into a single instrument. In order to evaluate the applicability of the LC/MS to forensic fiber dye analysis, a multi-stage chromatographic method using acidified water and acidified acetonitrile was developed that separated and identified a mixture of 15 basic and 13 disperse dye standards. The LC/MS also detected and analyzed dyes extracted from individual 0.5 cm acrylic and polyester fibers, demonstrating its applicability to this type of analysis. With regard to the analysis of disperse dyes in polyester fibers, the replacement of pyridine with acetonitrile in the extraction system allowed direct injection of the extracts into the LC/MS. The advantage of the LC/MS over other instrumental methods of textile dye analysis is demonstrated by the analysis and differentiation of three black acrylic fibers: two fibers had similar UV-Vis spectra but were differentiated with chromatography and two had similar UV-Vis spectra and chromatograms but were differentiated using the mass spectrometer.

Journal Article↗
PubMed2003

Effect of triphenyl bismuth on glass transition temperature and residual monomer content of acrylic bone cements.

Self-curing acrylic bone cements are widely used in the fixation of prosthetic implants in orthopaedic surgery. Commercial bone cements are rendered radiopaque by the addition of heavy metal salts of barium and zirconia. The addition of barium sulphate adversely affects the mechanical strength and fracture toughness of bone cement and despite the fact that it has low solubility in water; its slow release and subsequent toxicity have caused concern. In an earlier study triphenyl bismuth (TPB) was found to be a viable alternative as a radiopaque agent in acrylic bone cements, which provided enhanced homogeneity. In this study we report the effect of the inclusion of TPB on the thermal properties of PMMA-based bone cements using both conventional DSC and Modulated Temperature DSC. Furthermore, analysis of the residual monomer contents is reported analysed by NMR spectroscopy in order to ascertain the influence of TPB on the polymerisation reaction. The glass transition temperature (Tg) determined by DSC showed that the values decreased with the addition of increasing amounts of TPB through both blending and dissolution methods; however, the method of incorporating TPB did not influence Tg. The magnitude of reduction was dependent of the amount of TPB and was greatest in the case of highest concentration of TPB used. A TPB melting peak was observed in the 25 wt% TPBBC, suggesting a limit to the solubility of TPB. The residual monomer analysis showed that at 10 and 15% by weight of TPB in the cement caused no significant changes in the residual monomer content but 25 wt% of TPB exhibited a significantly higher residual monomer content.

Calorimetry, Differential Scanning↗
PubMed2005

Exothermal characteristics and release of residual monomers from fiber-reinforced oligomer-modified acrylic bone cement.

The aim of this study is to determine the peak temperature of polymerization, the setting time and the release of residual monomers of a modified acrylic bone cement. Palacos R, a commercial bone cement, is used as the main component. The cement is modified by adding short glass fibers and resorbable oligomer fillers, and an additional cross-linking monomer. The test specimens are classified according to the composition of the bone cement matrix (i.e., oligomer-filler, glass-fiber reinforcement, and/or cross-linking monomer). The exothermal characteristics during autopolymerization are analyzed using a transducer connected with a computer. The quantities of residual monomers were analyzed from different test groups using high performance liquid chromatography (HPLC). The DeltaT value for the oligomer filler and the glass-fiber-containing acrylic bone cement is lower than that for the unmodified bone cement (2.1 +/- 0.8 vs. 23.5 +/- 4.2 degrees C). The addition of a cross-linking monomer, EGDMA, shortens the setting time of the autopolymerization of the unmodified bone cement (7.1 +/- 0.9 min vs. 3.3 +/- 0.3 min). The quantity of the residual monomers released is higher in the modified bone cement than that in the unmodified cement. The cement that contains glass fibers and oligomer fillers has a considerably lower exothermal peak, whereas the total quantity of residual monomers released is increased.

Cementation↗
PubMed2000

Preparation and characterization of hyaluronate-hydroxyethyl acrylate blend hydrogel for controlled release device.

Hyaluronate-hydroxyethyl acrylate blend hydrogels were investigated as matrices for controlled release devices. Glycidyl methacrylate (GMA) derivatized HA (GMA-HA) was synthesized by coupling of GMA to HA in the presence of a suitable catalyst. These hydrogels were prepared by a free radical copolymerization of GMA-HA and hydroxyethyl acrylate. The water content of these hydrogels at equilibrium swelling in water (Ww) was 0.978+/-0.0073 (n=18); however, these hydrogel was mechanically tough and could be used as disk shape. The hydrogels swelling were found to depend on ionic strength and pH. The dried hydrogels quickly regained their original condition in water, and they swelled to more than 90% of its initial water contents after 30 min. This swelling-deswelling behavior was reproducible. The release of chlorpromazine HCl as a model cationic drug from the gels was suppressed significantly in water. The release increased with increasing the ionic strength and decreasing pH of bulk solutions.

Delayed-Action Preparations↗
PubMed1990

Changes in auditory function associated with 2-cyano-butyl-acrylate adhesive implanted in the middle ear of experimental animals.

The effects on auditory function caused by the implantation of 2-cyano-butyl-acrylate adhesive in the middle ear was investigated in experimental animals. Auditory brainstem responses to click stimuli were used to measure hearing thresholds prior to and following implantation of 2-cyano-butyl-acrylate adhesive in the middle ear of guinea pigs. A permanent and deep threshold shift observed at 2 months in 62% of the examined animals, suggested that this tissue adhesive is an ototoxic middle ear implant material and should not be considered in reconstructive middle ear surgery. The functional data correlate well with some of the previous morphological observations.

Animals↗
PubMed1989

Adaptation of acrylic resin dentures as influenced by the activation mode of polymerization.

With the advent of newer methods of activation of the polymerization of denture base resins, there is a need to compare dentures constructed using various modes of activation such as heat, light, and microwave energy. This study compares the dimensional accuracy of a conventional heat-activated acrylic resin poly (methyl methacrylate) with a new pour resin, a visible light-activated resin, and microwave-activated acrylic resin, all polymerized for denture bases. All groups showed a processing contraction; the poorest-fitting group was processed in a brass flask and a water bath at 70-100 C, using a heat-activated resin (Acron); the relatively new light-activated resin (Triad) produced dentures of intermediate accuracy, as did Acupac 20, when either heat- or microwave-activated. The two best-fitting groups were prepared from an autopolymerizing resin (PERform) and the microwave-activated resin (Acron MC).

Chemical Phenomena↗
PubMed2006

Setting properties of four acrylic and two calcium-phosphate cements used in vertebroplasty.

STUDY DESIGN: Experimental study conducted in the laboratory with six different bone cements. OBJECTIVES: To isolate the thermal properties of conventional and emerging bone cements used in vertebroplasty and to characterize their setting behavior. SUMMARY OF BACKGROUND DATA: The heat released during setting has been linked to the desirable effects of pain relief and tumor destruction and to the undesirable effect of thermal necrosis of surrounding tissue. However, there are currently no studies that disconnect the exothermic reaction of the cements from the media in which they occur. Before the combined thermal effect is examined, it is important to understand the setting properties of cements alone. METHODS: Thirty independent experiments were conducted with four PMMA cements (Cranioplastic, Vertebroplastic, Palacos LV-40, Antibiotic Simplex) and two calcium-phosphate cements (chronOS Inject and Biopex) in accordance with ASTM standard F 451-99a. A thermocouple was placed in the center of the cement mass, and the temperature-versus-time measurements were recorded. RESULTS: The calcium-phosphate cements took over half an hour to reach their maximum temperature, which was only 3-4 degrees C higher than the ambient temperature. The temperature increase for the acrylic cements was between 16 and 23 degrees C, and it took about 15 minutes to reach the maximum temperature. The variation within the groups was also important. CONCLUSION: The exothermic reaction of calcium-phosphate cements appears to be insignificant. Although the acrylic cements release considerably greater heat in a much shorter time period, it does not appear that their temperature is sufficiently high to cause extensive thermal injury. However, variations within each group must be considered along with the intended use when deciding on the cement to be used.

Calcium Phosphates↗
PubMed1975

Direct effects of acryl bone cement monomer on isolated heart muscle.

Experiments were carried out in isolated dog heart muscle to determine the direct effect of acryl bone cement monomer on the myocardial contractility. The monomer caused a dose-dependent decrease in the maximum velocity of shortening (Vmax) and the maximum force development (Fm), consequently resulting in a leftward shift of the force-velocity relation curves. There was also a concomitant decrease in work, power, the maximum rate of force development (max dF/dt) and time to peak force (TPF) from the onset of force development. These results indicate that acryl bone cement monomer exerts a direct negative inotropic effect on the myocardium and that the myocardial depression due to free monomer absorbed from the mixed bone cement into the systemic circulation during operation seems to be one of the major causes of the cardiovascular complications associated with the clinical application of bone cement.

Animals↗