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

Abstract

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.

Assessment of the flexural strength of two heat-curing acrylic resins for artificial eyes

“…2,3 These prostheses are manufactured with heat-curing acrylic resin, employing white pigments, resulting in a color similar to that of the natural sclera; colorless heat-curing acrylic resin is used to cover the blood vessels and artificial iris, and to provide a similar shine to that of the natural eye. Some authors [5][6][7][10][11][12][13][14] have taken the trouble to assess the mechanical properties of the acrylic resins for denture bases, by determining the masticatory forces to which they are submitted. In the present study, flexural strength of resins for fabricating prosthetic eyes was assessed based on the reports of patients, who relate frequent falling out of prosthetic eyes, whether during cleaning, or the procedures of inserting or removing them.…”

“…de Ensaios Ltd., Curitiba, PR, Brazil), in accordance with the three-point technique. 6,10,11 The values obtained were tabulated and submit-ted to the analysis of variance and the Tukey Test, at a level of significance of 1%.…”

“…The addition of acrylic fibers or acrylic stains did not affect the flexural strength of a microwave-cured acrylic resin. 6 Azzarri et al 7 (2003) affirmed that the curing processes of acrylic resins have been modified to improve the mechanical properties of these materials. Microwave energy offers advantages, such as a reduction in cure time and achievement of the plastic phase, greater homogeneity of the mixture and excellent prosthetic adaptation.…”

Estimate Zinc-Oxide Particles on PMMA Mechanical Properties

“…According to [22], the test patterns were constructed, and a rectangular-shaped pattern of 55mm × 10.5mm × 5mm (± 0.5mm) in length, width, and thickness was fabricated for the impact strength test. While the pattern dimensions of 65mm × 10.5mm × 5mm (± 0.5mm) were prepared for transverse strength.…”

O Uso De Energia De Microondas Para Polimerização De Resinas Acrílicas

“…6, 26, 21 SILVA, et al 30 (2002) mostraram ainda, que a adição de pigmentos intrínsecos e fibras acrílicas numa proporção de até 1,5% não altera a resistência transversal de uma resina polimerizada por microondas.…”