Evaluation of Dimensional Stability in Four Types of Impression Materials Using Digital Analysis

Dimensional precision of casts is essential for the quality of fixed prosthesis therapy, with the impression technique being a crucial component affecting this precision. This in vitro study is to evaluate the dimensional precision of casts generated from four varieties of impression materials.

Utilizing 20 specimens, four types of impression materials were fabricated and subsequently classified into four groups: condensation silicone impression material group (heavy and light body), condensation silicone impression material group (light body only), addition silicone impression material group (heavy and light body), and alginate impression material group. Dimensional stability was evaluated by acquiring imprints of an acrylic mold with three supports that replicate a slightly edentulous arch, which were then filled with stone. The stability was assessed by shooting photos with a Canon digital macro-lens camera, thereafter measuring the distances between the three posts using AutoCAD software (three lines were measured).

This study evaluated the dimensional precision of four frequently utilized impression materials in comparison to the primary standard. Dimensional accuracy was evaluated along three measurement lines, revealing substantial deviations from the standard for all materials (p  < 0.05). Among the investigated materials, addition silicone light & heavy body displayed the highest values (mean perimeter of 155.024 mm), which was closest to the control (perimeter of 163.405 mm), indicating minimal dimensional changes and exceptional dimensional stability. Conversely, Condensation silicone light & heavy body showed least values (146.06 mm) suggesting the least dimensional accuracy compared to the other three impression materials. Alginate and Condensation silicone light body showed comparable results when compared with each other (p  > 0.05) and were statistically better than Condensation silicone light & heavy and lower than addition silicone light & heavy. These findings highlight the significance of material selection for attaining accurate mold dimensions in clinical applications.

In summary Although the digital technique may be more dependable and less complicated way to evaluate the qualities of impression materials, addition silicone heavy and light body demonstrated superior dimensional accuracy when compared with the other three impression materials. In contrast, among the four impression materials tested, condensation silicone heavy & light body had the largest dimensional shifts, indicating the lowest degree of dimensional accuracy.