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.

Técnica de remoção de núcleos intra-radiculares com emprego do saca-pinos M&V / Intraradicular posts removal technique using M&V post puller instrument

Este trabalho tem por objetivo apresentar um método mecânico de remoção de núcleos intra-radiculares, eficaz e rápido, que requer mínima remoção de estrutura dental remanescente, com risco mínimo a fraturas e perfurações radiculares. Ao longo de dezoito anos de testes clínicos controlados, o saca-pinos M&V apresentou um índice de sucesso de 99 por cento, o que garante a sua utilização segura, principalmente nas regiões anterior e de pré-molares

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 percent w/w, respectively; acrylic fibers (AF) were added to groups GIV and GV in concentrations of 0.5 and 1.5 percent 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 37ºC 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