Effect of core materials on the dimensional accuracy of casts made of two different silicone impression materials: An experimental study

Background and Aim: Dimensional accuracy of impressions is crucial to the quality of fixed restorations. This accuracy can be highly affected by the type of core and impression materials. This study aimed to assess the effect of different core materials on dimensional accuracy of two silicone impression materials. Materials and Methods: In this in vitro study, three master core models were fabricated of amalgam, composite resin, and nickel-chromium. Of each model, 30 impressions were taken; 15 with additional and 15 with condensational silicone impression material. The accuracy of impressions of the three core materials was assessed by measuring two linear dimensions and one vertical dimension on the stone casts. Statistical Analysis: Data were analyzed with two-way analysis of variance and Scheffe post hoc test (alpha = 0.05). Results: Accuracy of the three measured dimensions was significantly affected by both the impression and core materials (P < 0.05). Additional silicone was significantly more accurate in linear dimensions, and impressions of the amalgam core were significantly more accurate than other cores in linear dimensions. Conclusion: Additional silicone impression material had more detail reproduction, and the impressions of amalgam core were more accurate than the composite and nickel-chromium core materials.