Effect of microwave disinfection on physical and mechanical properties of acrylic resins.
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 74 degrees C 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 (alpha=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.
Consani
Rafael Leonardo Xediek
RL
Department of Prosthodontics and Periodontics, Dental School of Piracicaba, University of Campinas, Piracicaba, SP, Brazil. rconsani@fop.unicamp.br
Vieira
Erica Brenoe
EB
Mesquita
Marcelo Ferraz
MF
Mendes
Wilson Batista
WB
Arioli-Filho
João Neudenir
JN
D000180:Acrylic Resins / Q000528:radiation effects*; D003799:Dental Stress Analysis; D004203:Disinfection / Q000379:methods*; D004866:Equipment Contamination; D006244:Hardness / Q000528:radiation effects; D008422:Materials Testing; D008872:Microwaves; D018583:Pliability / Q000528:radiation effects
D000180:Acrylic Resins