Effect of microwave disinfection on physical and mechanical properties of acrylic resins

• Autor(a) principal: Consant,Rafael Leonardo Xediek
• Data de Publicação: 2008
• Outros Autores: Vieira,Erica Brenoe, Mesquita,Marcelo Ferraz, Mendes,Wilson Batista, Arioli-Filho,João Neudenir
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Brazilian Dental Journal
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-64402008000400011
• topic: hardness; impact; flexural strength; acrylic resin; microwave disinfection

This study evaluated the effect of microwave energy on the hardness, impact strength and flexural strength of the Clássico, Onda-Cryl and QC-20 acrylic resins. Aluminum die were embedded in metallic or plastic flasks with type III dental stone, in accordance with the traditional packing technique. A mixing powder/liquid ratio was used according to the manufacturer's instructions. After polymerization in water batch at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling at room temperature, and submitted to finishing. Specimens non-disinfected and disinfected by microwave irradiation were submitted to hardness, impact and flexural strength tests. Each specimen was immersed in distilled water and disinfected in a microwave oven calibrated to 650 W for 3 min. Knoop hardness test was performed with 25 g load for 10 s, impact test was carried out using the Charpy system with 40 kpcm, and 3-point bending test with a crosshead speed of 0.5 mm/min until fracture. Data were submitted to statistical analysis by ANOVA and Tukey's test (?=0.05). Disinfection by microwave energy decreased the hardness of Clássico and Onda-Cryl acrylic resins, but no effect was observed on the impact and flexural strength of all tested resins.