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

Abstract

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