Effect of disinfectants on the tear strength of addition silicone impression material – An in vitro study

Addition silicone is a newer type of silicone impression material which has high dimensional stability, accuracy, and flexibility. They are mostly used for fixed restorations such as crowns and bridges. They have high tear strength; however, this strength may be altered upon disinfection. Disinfection of addition silicone prior use is important to reduce the microbial load. The aim of this study is to check whether there is any change in tear strength of addition silicone on disinfection with two commercially available disinfectants. Zhermack Elite HD + Putty material was tested in this study. Base and catalyst material was mixed and the material was cut into strips of dimension 70 mm × 10 mm × 2 mm. Five strips were immersed in sterillium and five strips were immersed in glutaraldehyde solution. These strips were then tested for their tear strength using Instron E3000 Universal Testing Machine. The values obtained were recorded in SPSS software version 22 (IBM SPSS Statistics for Windows, Version 23.0. Armonk, NY: IBM Corp.) for analysis and the P was obtained. The mean tear strength of Group 1, addition silicone immersed in sterillium disinfecting solution was found to be 7.148 ± 2.654 kN/m. The mean tear strength of Group 2, addition silicone immersed in glutaraldehyde disinfectant solution was found to be 7.326 ± 4.062 kN/m. An unpaired Student's t-test was done and P was found to be 0.235. The tear strength values between the groups was statistically not significant. Hence the tear strength of addition silicone was found to be greater in the glutaraldehyde disinfectant solution group.