ABSTRACT
El objetivo de este trabajo fue evaluar el desgaste abrasivo por cepillado in vitro de la resina compuesta 4Seasons, de dos colores diferentes (A3 y C4) y polimerizadas por dos diferentes tiempos (20 e 40 s), utilizando cepillo dental y dentífrico; también se uso como material de referencia, el PMMA. Fueron confeccionados 10 especímenes, para cada uno de los 5 grupos (PMMA, A3 20s, A3 40s, C4 20s, C4 40s). Después de su confección, cada espécimen era almacenado en agua desmineralizada a 37 ± 2 ºC, por 24 horas, regularizados con lija; después del lavado en ultrasonido, volvían a ser almacenados en las mismas condiciones por 7 días. El cepillado fue realizado en una máquina para desgaste por cepillado, aplicándose una carga de 3N, con frecuencia de 4,5 ciclos/seg; el período de cepillado de un espécimen comprendía 150,000 ciclos. Fueron realizados 5 lotes de cepillado, de modo que un espécimen de cada material de cada grupo fuese sometido a cada una de las posiciones ocupadas por los 10 cepillos. La cantidad de masa pérdida fue calculada por pesaje (pre y post cepillado). Este trabajo también fue ilustrado con gráficos de rugosidad y MEB. La tasa media de desgaste fue de 2,8 mg para PMMA, de 5,5 mg para A3-20s, 4,7 mg para A3-40 s, 5,4 para C4-20s y 4,2 mg para C4-40s. ANOVA mostro que no hubo diferencia significante entre los grupos, para p=0,166. Concluyéndose que no existió diferencia de resistencia al desgaste abrasivo entre los grupos
To evaluate abrasive wear, by weight changes, of a resin composite to in vitro toothbrushing, of two different colors (A3 and C4), cured by two times (20 and 40 s). Resin composite 4Seasons was material studied and PMMA was used as reference material. Ten cylindric samples had been prepared for each one of the five evaluated groups (PMMA, A3 20s, A3 40s, C4 20s, C4 40s). After confection, samples were immersed in deionized water, at 37± ºC, for 24 h, and then regularized by abrasive gritting with sandpaper, after that, were cleaned in ultrasound bath, and restored to the same described conditions, for 7 days. The toothbrushing was then conducted in a proper machine that holds 10 specimens, with 3 N load of each toothbrush on the respective sample using dentifrice and water. 150.000 cycles were applied per group. Five lots of toothbrushing had been performed; in a way that one sample of each group had been submitted to the brushing action at one position in the machine. The amount of weight loss for each sample was calculated by means of weighting. Roughness and MEV were also evaluated. Data were analyzed with one-way ANOVA. The average rate of wear was of 2.8 mg for PMMA, 5.5 mg for A3-20s, 4.7 mg for A3-40 s, 5.4 for C4-20s, and 4,2 mg for C4-40s. One-way ANOVA showed no significant difference between groups (p=0.166). It was possible to conclude that difference of the resistance to the abrasive wear between the studied groups did not exist