An evaluation of effect of immersion and spray disinfection on dimensional stability of dental impressions -A comparative study in vitro

The purpose of this study was to study the effect of disinfectants on impression materials.

Three dies were used for taking impressions. A metallic die representing prepared single unit crown was used for polysulfide, acrylic maxillary arch with full compliment of teeth was used for alginate and maxillary edentulous die was used for zinc oxide-eugenol impressions. Three disinfectants; povidineiodine 0.5%, chlorhexidine gluconate 0.2% and 2% neutral glutaraldehyde were used. Impressions were disinfected by immersion and spray for 30 minutes each. Measurements from each cast were taken and compared with control using one-way analysis of variance(ANNOVA). The inter-comparison of treatments was done using least significance difference(LSD) at 5% level of significance.

Casts secured from polysulfide impression has shown increase in width and decrease in height which was found to be statistically insignificant. Irreversible hydrocolloid casts have shown insignificant changes with glutaraldehyde, but significant changes were found with other two treatments. Zinc oxideeugenol impression casts showed insignificant changes.

Accuracy of all three impression materials was least disturbed by glutaraldehyde. Irreversible hydrocolloid has shown significant changes with povidine-iodine and chlorhexidine gluconate but insignificant changes with glutaraldehyde. Zinc oxide-eugenol impressions were least affected by three disinfectants.