Effect of different impression techniques on the dimensional accuracy of impressions using various elastomeric impression materials: an in vitro study

Production of exemplary crowns and fixed partial dentures depends upon the usage of impression material and its technique of usage that accurately reproduces prepared teeth and their relationship to the adjacent oral structure. To evaluate the linear dimensional accuracy of the elastomeric impressions using various impression techniques using different combinations of viscosities of impression materials. Crown preparation was done in a dentulous acrylic resin denture base model with six natural teeth embedded into it was made to represent the dentulous maxillary arch. A total of 55 impressions were obtained and poured in die stone using various impression techniques with different combinations of viscosities of impression materials. Among the six techniques used, the heavy body light body two-step technique using custom tray showed the least distortion which was closely followed by the putty wash two-step technique with 2 mm spacer using stock tray. The study revealed that the heavy body light body two-step technique with custom tray provided the best results. Dimensional accuracy of impressions is very much required for precisely fitting of prosthesis. This study may be helpful to select the technique and materials as per clinical requirement of accuracy of impressions.