Dimensional stability of seven elastomeric impression materials immersed in disinfectants.

Dental impressions can increase the transmission of microorganisms and infections. The purpose of this study was to assess the influence of three disinfectant solutions on the dimensional accuracy of seven elastomeric impression materials. Impressions of a test block were either left untreated (controls) or treated by immersion in a disinfectant solution. Measurements were taken on die stone replicas of the impressions. Comparisons were made between (1) the measurements for the variations in the nontreated impressions and those for the treated impressions and (2) measurements for the treated impressions and the test block. Results indicated that the aminoamphoteric agent or glutaraldehyde derivative-based solutions created little change in relation to the initial dimensional accuracy of the impression products. However, the sodium hypochlorite solution often leads to expansion by comparison with controls. By comparison to the test block, this expansion then makes it possible in most cases to obtain better dimensional accuracy than initially. Within the limits of this study this expansion could lead to an improvement in clinical fixed prosthodontic procedures.