Effect of repeated disinfections by microwave energy on the physical and mechanical properties of denture base acrylic resins

Brazilian Dental Journal

Rafael Leonardo Xediek Consani²  Douglas Duenhas De Azevedo¹  Marcelo Ferraz Mesquita²  Wilson Batista Mendes¹  Paulo César Saquy¹ 

[1] ,State University of Campinas Piracicaba Dental School Department of Prosthodontics and PeriodonticsPiracicaba SP ,Brazil

关键词: hardness;    impact;    flexural strength;    acrylic resin;    microwave disinfection;   

DOI  :  10.1590/S0103-64402009000200008

来源: SciELO

【 摘 要 】

The present study evaluated the effect of repeated simulated microwave disinfection on physical and mechanical properties of Clássico, Onda-Cryl and QC-20 denture base acrylic resins. Aluminum patterns were included in metallic or plastic flasks with dental stone following the traditional packing method. The powder/liquid mixing ratio was established according to the manufacturer's instructions. After water-bath polymerization 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 and finished. Each specimen was immersed in 150 mL of distilled water and underwent 5 disinfection cycles in a microwave oven set at 650 W for 3 min. Non-disinfected and disinfected specimens were subjected to the following tets: Knoop hardness test was performed with 25 g load for 10 s, impact strength test was done using the Charpy system with 40 kpcm, and 3-point bending test (flexural strength) was performed at a crosshead speed of 0.5 mm/min until fracture. Data were analyzed statistically by ANOVA and Tukey's test (α= 0.05%). Repeated simulated microwave disinfections decreased the Knoop hardness of Clássico and Onda-Cryl resins and had no effect on the impact strength of QC-20. The flexural strength was similar for all tested resins.

【 授权许可】

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