effects of mixing a disinfecting solution instead of water with gypsum powder Part II accuracy rep in ducibility, surface finish, and surface hardness of the resultant gypsum casts

A study was conducted to evaluate the effects of mixing dental stone powder with Cidex [2% glutaraldehyde] solution instead of distilled water on the accuracy, reproducibility, surface finish, and surface hardness of the stone casts. Upper jaw model with four teeth and ADA die were used as master models. Five dental stone products were selected, from each two types of stone casts were made for each master model. The first type was mixed with distilled water and the second type was mixed with Cidex solution. 20 samples for the surface hardness test were made from each dental stone, 10 were mixed with distilled water and the other 10 were mixed with Cidex. Linear dimensional changes were measured on the ADA die casts and dimensional changes in three dimensions were measured on the upper jaw model casts. Measurements were made by using an electronic measuring device [Micro-Vu, Model H-14, Windsor, California] capable of measuring to the nearest 0.0001 mm. Reproducibility were evaluated on the ADA die casts and the surface hardness was measured by the vickers hardness test

effect of mixing a disinfecting solution instead of water with gypsum powderPart1: microbiological study of the resultant gypsum cast

A method to sterilize the gypsum cast to prevent cross-contamination was investigated in the present study. Different dilution of cidex solution [2%, 1.5%, 1% and 0.5% glutaraldehyde] were mixed with stone powder instead of water. Microbiological study was done for the resultant stone casts after 1 hour and 2 hours from pouring contaminated impression. From the results obtained, it was concluded that, when cidex solution is mixed with stone powder instead of water it reduces or eliminates the microbial load of the resultant stone casts. Full strength cidex [2% glutaraldehyde] give the best results since it eliminates all the microbial load from the stone casts sterilize it, so, it is the recommended concentration of cidex to replace water in the stone mix. When cidex solution is diluted with water and mixed with stone powder, it reduces the microbial load but it fails to sterilize it completely. Stone casts which are produced by mixing cidex solution possess antimicrobial property. The highest level is achieved when cidex 2% is mixed with the stone powder