Storage time effect on marginal fit of full crown patterns made of wax, autopolymerized and light polymerized resin materials

The purpose of this study was to evaluate the marginal fit of full crown patterns made from three materials after storing at ambient temperature for 1 hour and 24 hours. The marginal gaps of full crown patterns made from wax, autopolymerized and visible light cured acrylic resin materials were compared. The patterns were fabricated on stone (Vel Mix) working dies made from polyvinyl siloxane impressions of an American Dental Association full crown stainless steel die. Thirty patterns of each material were stored on their corresponding stone dies at room temperature after fabrication for 1 hour and 24 hours. The marginal gaps of patterns were evaluated on the metal master die. The data were subjected to one-way and two-way analysis of variance (ANOVA) and paired t-test. All the tests were conducted at 0.05 level of significance. The results indicated that patterns made from each of the three materials (wax, autopolymerizing and visible light-cured resins) had better marginal fit at 1 hour than at 24 hours after fabrication. Under the two storage conditions, the wax patterns showed the greatest marginal gap followed by visible light-cure resin and autopolymerizing acrylic resin.