Wettability, imbibition, and mass change of disinfected low-viscosity impression materials

Statement of problem. There is an ongoing effort by dental manufacturers to create impression materials with improved wetting properties. Disinfection solutions may alter the surface characteristics of these newer materials. Purpose. This study compared wettability, imbibition, and mass change of various recently introduced automixed low-viscosity addition silicone and polyether materials before and after immersion disinfection. Material and methods. The Wilhelmy technique was used for deriving wetting properties of 5 addition silicone materials (Clinician's Choice Affinity, Clinician's Choice Superhydrophilic [experimental], Kerr's Take One, 3M's Imprint II, and Dentsply's Aquasil LV) and 2 polyether materials (ESPE's Permadyne Garant and Impregum Garant). Conditions included a control with no disinfection (0 hours), as well as 1/2 hour of immersion disinfection in a full-strength solution of 2% acid glutaraldehyde disinfectant (Banicide). Weight changes before and after disinfection and weight loss in air were measured over an 18-hour period to detect imbibition and mass change over time. The data were analyzed with a 1-way analysis of variance at alpha=0.05, with n=3 for advancing (ACA) and receding (RCA) contact angles and n=2 for imbibition and mass change. Results. Statistical significant differences in wettability (P<.001) were found among nondisinfection control groups, as well as among 1/2-hour disinfection groups. Polyethers were the most wettable materials overall. Impregum Garant polyether demonstrated significantly lower RCA for the control (48.4 degrees) and at 1/2 hour of disinfection (51.8 degrees). The 2 polyethers and Take One lost mass, whereas Aquasil LV gained mass in air; however, all materials exhibited some degree of imbibition during disinfection. Conclusion. Within the limitations of this study, the 2 polyether materials tested exhibited significantly lower ACA's and RCA's compared with the 5 addition silicones tested. Imbibition for the 2 polyether materials was significantly higher (P<.001). Polyether materials lost significantly more (0.6% to 0.8%) and Aquasil LV gained significantly more (0.6%) mass in air.