Effects of Autoclave Sterilization and Immersion Disinfection on the Dimensional Stability of Vinylsiloxanether Elastomeric Impression Material – An In Vitro Study

Objectives: To compare time dependent effects of autoclave sterilization and immersion disinfection on the dimensional stability of vinylsiloxanether impression material.

Methods: Impressions of stainless steel die, constructed in accordance with ADA/ANSI specification No. 19, were made of Vinylsiloxanether (Identium® – medium). Samples were divided into three groups each containing twenty specimens (n=20). Group A samples were autoclaved at 134°C & 20 psi for 5 minutes. Group B samples were disinfected with 3% Didecylidimethyl ammonium chloride solution (practice safe soak®) for 3 minutes, while group C served as a control group. Impressions were scanned with scanner (HP deskjet 2050) and analyzed using Adobe reader XI software. Dimensional changes were calculated for two time intervals i.e. after one hour and after twenty-four hours.

Results: Statistically significant difference in percent dimensional change was found between the samples of group A & B (P = 0.026) after twenty-four hours. The dimensional change after twenty-four hours of autoclave sterilization was also significantly different from the values obtained at one hour of same samples (p = 0.007). No significant difference was found between readings at one hour of group A & B, A & C and B & C. Similarly no statistical difference was found between group A & C and B & C after twenty-four hours of storage.
Conclusions: Dimensional changes observed at different time intervals were under the acceptable range of ADA specification for elastomers (≤0.5%). Vinylsiloxanether can safely be sterilized and disinfected without changing dimensions deleteriously. It is desirable to cast autoclaved vinylsiloxanether impression material after one hour.