Linear dimensional accuracy of epoxy resin and stone dies.

1 Ideally, d ie material for fixed restorations should be dimensionally accurate, durable, consistent, and of reasonable cost. It should also be simple to manipulate, compatible with currently used impression materials, able to reproduce fine details, and have a stable shelf life. Toreskog et al.’ tested eight different classes of die materials and concluded that no one material was superior. Newman and Williams’ also concluded that “an ideal universal die material is yet to be produced.” There have been several reports on epoxy resin dies.‘.’ Although they have been shown to have superior compressive strength and abrasion resistance,3 their dimensional accuracy has been poor due to shrinkage.” Stone dies are still considered the standard for most fixed partial denture construction. The relative accuracy of stone dies is well documented in clinical and bench studies.’ However, lack of durability during the increased handling that is inherent in extensive reconstructive dentistry often creates problems in the laboratory. The newer formulations and techniques for epoxy resin are said to produce dies that are comparable to stone dies in dimensional accuracy.” If a resin die is as dimensionally accurate as a stone die, its use would be justified because of superior resistance to fracture and abrasion. The purpose of this study was to compare the linear dimensional accuracy of epoxy resin dies to stone dies.