Effect of microwave irradiation on disinfection, dimensional accuracy, and surface porosity of dental casts

To evaluate the effectiveness of different microwave irradiation exposure times onthe disinfection of dental stone samples immersed in different solutions, and its affecton the dimensional accuracy and surface porosity.Dental stone casts were inoculated with an isolate of Bacillus subtilis toexamine the efficiency of microwave irradiation as a disinfection method whileimmersed in different solutions; water, 40% sodium chloride, or without immersionfor different durations. Dimensional accuracy and surface porosity were alsoevaluated.Significant reduction in colony counts of Bacillus subtilis were observed after 5minutes of microwave irradiation of immersed dental casts in water and NaClsolution. No evidence of growth was observed after 10 minutes while immersed inwater or NaCl solution. Dimensional accuracy of dental stone was significantlyaffected by immersion in water for 5 or 10 minutes during exposure to microwaveirradiation while it was insignificant affected by immersed in NaCl solution, or in dryair. The surface porosity of dental stone was significantly affected by the immersed inwater and NaCl solution for 5 or 10 minutes while it was insignificantly affected bydry conditions during microwave disinfection.Immersion the dental stone casts improved the effectiveness of microwaveirradiation as a disinfection method. The dimensional accuracy and surface porositywas adversely affected but within the clinical limitation..