An in vitro study to evaluate the effect on dimensional changes of elastomers during cold sterilization

This study was planned to evaluate the dimensional stability of elastomers during cold sterilization or immersion disinfection and also to evaluate the same, along with acrylic resin trays which are used in clinical practice.

A study mold according to revised American Dental Association. Specification no. 19 was used. Polyether, polyvinyl siloxane (PVS) (heavy body), PVS (regular body) and Hydrophilic addition reaction silicon (medium body) were selected for study. 2% glutaraldehyde and 0.525% sodium hypochlorite were the disinfectants used. The study was divided into group-I and group-II. In group-I study, 24 specimens of each impression material were prepared. Eight immersed in 2% glutaraldehyde, eight in 0.525% sodium hypochlorite and rest eight allowed to dry bench cure. After 16 h, the specimens measured under Leica WILD stereomicroscope and dimensions compared with master die. In group II study, 24 specimens of the material with the least dimensional changes were prepared and adhered to 24 acrylic resin disks using tray adhesive. Same immersion procedure was followed as in group I. The data were analyzed by one-way ANOVA and Tukey's multiple tests.

Of four impression materials used, PVS (heavy body) was the most dimensionally stable, and Polyether was the least dimensionally stable in both the groups.

Within the limitation of the study, PVS (heavy body) was most stable, and polyether was least stable of all the impression materials.