The effect of microwave disinfection on compressive and tensile strength of dental stones

Abstract

It has been shown that microwave irradiation can be used as a disinfection technique of dental stone casts; however, there are always worries about mechanical damage to casts following irradiation. The aim of this study was to evaluate the effect of microwave irradiation at an energy level of 600 W for 3 minutes on the compressive strength (CS) and diametral tensile strength (DTS) of type III and IV stone casts. Materials and methods: In this in vitro study, 80 cylindrical stone models (20 40 mm) were prepared and divided into 8 groups of 10. The DTS and CS of the specimens were measured by a mechanical testing machine at a crosshead speed of 0.5 cm/min after 7 times of frequent wetting, irradiating and cooling. The results were analyzed by Students t-test. Results: Microwave disinfection significantly increased DTS (p<0.01) of the two stone types. Conclusions: Under the conditions described, microwave disinfection increases DTS of type III and IV stone casts without any effects on CS.