A comparative study to determine the dimensional accuracy of different impression materials

Abstract

Background: The accuracy and dimensional stability of dental impression materials are of great importance, since a material which shrinks, expands or warps during or after removal from the mouth will result in an inaccurate model and potentially, a badly-fitting prosthesis. The purpose of this study was to evaluate the dimensional accuracy of the impression materials immediately after setting and also to determine the change in dimensional accuracy after 24 hours. Materials and Method: Four impression materials were selected among which two were hydrocolloids and two were elastomers. Fifteen samples of each were experimentally tested immediately and 24 hours after sample preparation. Data obtained were subjected to t-test and analysis of variance for statistical comparisons at a 5% level of significance. Results: The linear difference in measurements were recorded immediately and 24 hours after setting. The changes in dimensional accuracy with respect to time were statistically analysed and it showed no statistically significant difference between the materials both immediately and after 24 hours. Conclusion: Within the limitations of the study, It can be concluded that there were similar results for dimensional accuracy for all the materials tested immediately after sample preparation but there was considerable disparity with the same tested after 24 hrs for hydrocolloids and not much of difference was noted for elastomers.