Effectiveness of microwave sterilization on soft lining material

الملخص EN

The aim of this study was to evaluate the effectiveness of microwave irradiation sterilization on Molloplast –B soft denture liner.

Materials and Methods : Sixty specimens of Molloplast –B soft den-ture liner were fabricated in a standardize procedure and autoclaved.

The total 60 specimens were di-vided into 4 groups.

Each group has 15 specimens inculated with Brain Heart Infusion Broth (BHI) media containing one of the tested microorganisms (Staphylococcus aureus, Bacillus subtilis, Pseudo-monas aeroginosa and Candida albicans).

Then the 15 specimens in each group was further divided into 3 subgroups: group C (positive control); 5 none irradiated specimens, group D (dry microwave treat-ment); 5 specimens placed in a dry beaker and microwave irradiated at 540W for 6 minutes, group W (wet microwave treatment; 5 specimens immersed in distalled water and irradiated in the same manner as group D.

After incubation of all specimens for 24 hours at 37°C, the specimens were got vortex and then the replicated specimens (100μL) of suspensions were plated on 4 selective media appropriate for each organism.

All plates were incubated at 37°C for 48 hours.

After incubation, colonies were counted.

Further 7 days incubation for microwaved specimens was done to verify the effectiveness of dry and wet microwave sterilization.

Results : Significant reduction in cfu/ml of all microorganisms was observed at 48 hours.

No growth of C.

albicans was recorded at 48 hours and after 7 days incuba-tion.

Conclusions : Microwave irradiation at 540W for 6 min in dry and wet conditions was proved to be effective in the disinfection of soft lining material specimens contaminated with Staph.

aureus, Ps.

aeruginosa and B.

subtilis.

Wet treatment was more effective than dry one.

Dry and wet microwave treatment sterilized specimens contaminated with C.

albicans.