The Effect of Microwave Disinfection on the Dimensional Change of Acrylic Resins.

Aims: To evaluate the effect of the microwave disinfection on the dimensional changes of the heat– cured acrylic resin. Materials and Methods: Heat–cured acrylic resin was used in this study. Thirty two disk–shaped specimens with reference points were prepared to evaluate the linear dimensional changes of the heat–cured acrylic resin that sterilized by microwave irradiation and by chemical solutions chlorhexidine and sodium hypochlorite. The specimens were divided into four tested groups, eight specimens for each group. Group I as control group and other groups divided according to the sterilization method. The dimensional change was evaluated with an Electronic Digital Caliper. Mean values wear compared statistically with: One–way Analysis of Variance (ANOVA), followed by Duncan ' s Multiple Range Test to determine the significant different among the tested groups at (p≤0.05) level of significance. Results: They showed that there was a highly significant difference of the means values of the linear dimensional change among the four tested groups. Specimens sterilized by microwave irradiation have a higher value than that sterilized by the chemical solutions. Conclusions: The results of this study appeared that sterilization by the microwave irradiation produce a significant effect on the dimensional stability of the heat–cured acrylic resin, while sterilization by chemical solution produce no significant difference.