The dimensional accuracy of vinyl Siloxane ether and polyvinyl Siloxane in one step and two step impression techniques when the finish line is Subgingival

The accuracy of impression materials in terms of both dimensional stability and detail reproduction is necessary for FPD and implant prosthesis. For this purpose polyvinyl siloxane impression material have become extremely popular. This material is known for their excellent elastic recovery, optimal accuracy, adequate tear resistence, satisfactory handeling characteristics and virtually ideal dimentional stability. VSE (Vinyl siloxane ether) is newly introduced material with additional benefits of hydrophilic properties. In the present study we are comparing the effect of one step and two step impression technique on accuracy when finish line is within the sulcular area by using PVS (addition silicon) and VSE. A standardized stainless steel die was fabricated for making impressions with Polyvinyl Siloxane Ether (Group A) and Vinyl Polysiloxane (group B). 20 impressions of each group were made. Further the two groups were subdivided into one (one step impression technique) & two (two step impression technique). The accuracy of impression material was measured using 3 D scanner. The data obtained was subjected to statistical analysis. The mean difference in dimensional change between the four groups was not statistically significant (P(0.05). However the results revealed that there was higher mean dimensional accuracy with two step impression technique of vinyl polysiloxane impression material.