COMPARATIVE ANALYSIS OF DIFFERENT IMPRESSION MATERIALS IN FIXED PROSTHODONTICS

Abstract

Background: The success of fixed dental prostheses is critically dependent on the accuracy of the final impression. Elastomeric materials like polyvinyl siloxane (PVS), polyether, and condensation silicone are widely used, but a comparative analysis of their performance is essential for clinical decision-making. This study aimed to compare the dimensional accuracy and surface detail reproduction of these three common impression materials.

Methods: An in vitro experimental study was conducted using a standardized metallic master die. A total of 60 impressions were made, divided equally into three groups (n=20 each) based on the material: PVS, polyether, and condensation silicone. All impressions were taken using a custom acrylic tray and a two-step putty-wash technique. The resulting stone casts were evaluated for dimensional accuracy using a digital measuring microscope and for surface detail reproduction under 20× magnification. Data were statistically analyzed using one-way ANOVA and Chi-square tests.

Results: PVS demonstrated the lowest mean dimensional discrepancy (0.018 mm), followed by polyether (0.025 mm) and condensation silicone (0.041 mm), with statistically significant differences (p < 0.05). For surface detail reproduction, PVS achieved the highest rate of complete reproduction (90%), compared to 75% for polyether and 50% for condensation silicone. Furthermore, PVS impressions had the fewest defects (85% defect-free), while condensation silicone had the most.

Conclusion: Within the limitations of this study, polyvinyl siloxane (PVS) proved to be the most accurate and reliable impression material, exhibiting superior dimensional stability, finest surface detail reproduction, and the fewest defects. Polyether performed satisfactorily, while condensation silicone showed the lowest performance. PVS remains the preferred material for high-precision fixed prosthodontic procedures.