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Notizen: 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.〈section xml:id="abs1-2"〉〈title type="main"〉Materials and MethodsSelfcured 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.〈section xml:id="abs1-3"〉〈title type="main"〉ResultsThe standard of radiopacity (〈inlineGraphic alt="geqslant R: gt-or-equal, slanted" extraInfo="nonStandardEntity" href="urn:x-wiley:1059941X:JOPR213:ges" location="ges.gif"/〉aluminum radiopacity) is met at TPB levels of 〈inlineGraphic alt="geqslant R: gt-or-equal, slanted" extraInfo="nonStandardEntity" href="urn:x-wiley:1059941X:JOPR213:ges" location="ges.gif"/〉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.〈section xml:id="abs1-4"〉〈title type="main"〉ConclusionsAt 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.

Notizen: Purpose Methods of incorporating radiopaque triphenylbismuth into an experimental compression-molded and injection-molded heat-polymerized resins were determined. The transverse flexural properties, radiopacity, and color stability of the resins containing triphenylbismuth were then compared with a commercially available, compression-molded denture resin.Materials and Methods Varying levels of triphenylbismuth were added to both the monomer and polymer in heat-polymerized denture resin systems to determine the level of the additive that was necessary to achieve a radiopacity similar to 0.2 mm of copper with minimum resin porosity. Specimens were then prepared by incorporating 0% or 30% wt/wt triphenylbismuth into resins. The commercially available polymethyl methacrylate resin served as a benchmark for physical property comparison, and no additive was included during its polymerization. At 30% wt/wt triphenylbismuth, resin color stability, transverse deflection, and radiopacity were evaluated using methods described in International Standards Organization Standard 4049 and American Dental Association Specification No. 12. The transverse deflection results among the resin groups were compared with a reference resin using the Kruskal-Wallis method (α= 0.05).Results Incorporation of triphenylbismuth into the monomer of the injection material, resulting in 30% wt/wt in the polymerized resin, produced a level of radiopacity similar to 0.2 mm copper. Although the injection-molded resin with 30% wt/wt triphenylbismuth remained translucent, the compression-molded resin was opaque, indicating excessive air-entrapment porosity. The additive caused a faint yellowing in both types of resins, but color stability was not affected. Transverse deflection of the injection-molded resin (4.5 ± 0.5 mm) and the injection-molded resin with triphenylbismuth (3.8 ± 1.7 mm) was greater than that of the experimental resin (3.5 ± 0.2 mm), which was equal to the commercial resin (3.6 ± 0.2 mm). Triphenylbismuth at 30% wt/wt significantly reduced transverse deflection for the experimental resin (2.6 ± 0.5 mm).Conclusions Triphenylbismuth at a final concentration of 30% wt/wt can be added to polymethyl methacrylate injection-molded resins to provide a high level of detection on chest or abdominal radiographs without adversely affecting resin color stability and transverse deflection.