Comparative Evaluation of Surface Detail Reproduction and Dimensional Stability of Poly Ether, Vinyl Siloxane, and Vinyl Siloxane Ether Impression Materials: An In vitro Study

Introduction:

Impression making is an integral part of prosthetic dentistry. Development of material science has allowed integrating qualities of hydrophilic polyether and hydrophobic polyvinyl siloxane into a newer hybrid material, vinyl polysiloxane (VPS) ether. This study was aimed to compare the VPS ether with the polyether and polyvinyl siloxane in terms of accuracy and dimensional stability.

Materials and Methods:

Stainless steel dies with the American Dental Association specification 19 were made. Die has three horizontal and two vertical lines which are used for taking the impression. Two cross-points at the junction of the vertical lines with line 2 were marked as x and x' and served as beginning and end points of measurements for dimensional accuracy. Accuracy was evaluated 30 min after making each impression. If at least two of the three horizontal lines were reproduced continuously between cross-points, this impression was considered satisfactory. The specimens are poured with Type IV gypsum product and allowed to set completely for 24 h. Then, dimensional stability was measured in the model by measuring the distance between the two lines and comparing the distance with the measurement of line on metal die, which was used to make the impression.

Results:

The mean value obtained for light- and medium-bodied VPS ether was 0.05370 and 0.05330 and for light and medium-bodied polyvinyl siloxane was 0.06370 and 0.07150, respectively. The mean value for polyether monophase was 0.06430. Two-way ANOVA and post hoc test showed statistical significance.

Conclusion:

The newer VPS ether material showed good surface detail reproduction and dimensional stability when compared with polyvinyl siloxane and polyether.