ISSN:
1365-2842
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
summary Heat-activated acrylic denture base resin is widely used for its many good attributes, although it does show polymerization shrinkage. Although several processing methods have been developed for the purpose of minimizing polymerization shrinkage, some warpage after processing is inevitable. The purpose of this study was to examine the development of residual stress relaxation in resin denture base samples in the region where shrinkage was restricted, in order to clarify how cooling variations in the stone mould influenced the shrinkage. Flat, dumbbell-shaped specimens were used. Thermocouples and strain gauges were embedded in the resin for measuring temperature and strain during the dough-stage of resin packing. To clarify stress relaxation in the stone mould, specimens were removed from the stone mould by de-flasking 4 h after the start of cooling at room temperature (control), and 12 and 24 h from the start of gradual cooling in a water bath. The strain differences between before and after removing from the stone mould for the control, and 12- and 24-h experimental groups were 1793, 1354 and 1093 μɛ, respectively. Our results suggest that a gradual cooling course for 12 h or more after processing a heat-activated acrylic denture base is effective for lessening deformation of the prosthesis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2842.2004.01393.x
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