Marginal accuracy of interim restorations fabricated from four interim autopolymerizing resins

Statement of problem. One of the most important requirements for interim restorations is good marginal adaptation. Polymerization shrinkage of interim restorative materials can jeopardize the marginal integrity of interim restorations. Purpose. The purpose of this study was to compare the marginal accuracy of interim restorations made with 4 interim materials. Material and methods. A direct technique was used to fabricate 44 interim restorations with 4 materials: Protemp 3 Garant, Trim II, Tempron, and Acropars (n=11). The interim restorations were made on a prepared molar-shaped metal die with a vinyl polysiloxane impression as a matrix. Marginal discrepancy of interim restorations was measured at the midpoint of buccal, palatal, mesial, and distal Surfaces of metal die finish line with a microscope at X 100 magnification. Comparisons were made with 1-way analysis of variance and the Duncan multiple range test (alpha=.05). Results. The mean marginal discrepancies of Protemp 3 Garant, Trim II, Tempron, and Acropars were 0.059, 0.063, 0.068, and 0.102 mm, respectively. Acropars exhibited the most marginal discrepancies and was significantly different from the other materials tested (P<.001). However, there were no statistical differences between the other 3 materials tested. Conclusions. Interim restorations made from the Bis-GMA and conventional acrylic resins tested produced comparable marginal fit. Acropars demonstrated significant increases in marginal gap size.