Efeito da escovação mecanica e da termociclagem sobre dureza e rugosidade superficiais de reembasadores resilientes / Effect of mechanical brushing and ageing by thermal cycling on hardness and roughness surface of resilient soft liners

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The aim of this study was to evaluate the effect of mechanical brushing and thermocycling on hardness and roughness of three resilient definitive lining materials: 1) auto (Sofreliner MS), 2) heat-polymerized (Molloplast-B) silicone bases; and 3) auto-polymerized plasticized acrylic resin (Dentuflex). To prepare the samples, silicone rubber matrixes were made and placed in a flask to obtain a cast pressed mold, and then filled with resilient lining materials, handled according to the manufacturer?s directions. All samples were submitted to surface roughness readings in a roughness readings machine (SURFCORDER SE 1700 ? Kosaka Laboratory) and hardness readings in a Shore A durometer (GS ? 709 Teclock, Osaka, Japan). After the readings, the samples were assigned into 6 groups of 10 each, half of which were submitted to thermocycling treatment in a thermal cycler machine (MSCT ? 3 PLUS) for 2.000 cycles at temperatures ranging from 5±1oC to 55±1oC and a 60-second dwell time. The other half was submitted to a mechanical brushing simulation in an MSEt brushing machine followed by thermocycling. The samples were submitted to 30.000 strokes with linear brushing movements, under a 200 g static load pressure. Toothpaste solution was injected every one-minute break. Then new readings of hardness and roughness were done, and the values were submitted to variance analysis test followed by Tukey test, with 5% of significance. Dentuflex showed the highest initial values for both roughness and hardness, followed by Molloplast-B and Sofreliner MS. After thermocycling, Dentuflex and Sofreliner-MS showed a statistically significant increase in hardness values. After mechanical brushing, Dentuflex showed a decrease and Sofreliner MS an increase in roughness values. After mechanical brushing followed by thermocycling, all materials showed similar roughness values (statistically significant), probably due to the Dentuflex polished surface, the Sofreliner MS abrasion and the remained features of the Molloplast-B

ASSUNTO(S)

denture materiais dentarios protese dentaria completa dental materials complete

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