In general, studies of commercial resin matrixes indicate volumetric shrinkage in the curing process as great as seven percent, with most undergoing shrinkage of two or three percent (Seghatol & Durand, 1999).
In dentistry, the comparatively small dimensions of the products composed of polymers and the specific point-load stresses sometimes encountered by dentures magnifies the undesirable effects of even small percentages of incomplete polymerization and volumetric shrinkage. Moreover, dental materials are typically designed to fit with much closer mechanical tolerances than two or three percent if they are expected to perform as designed throughout their intended lifespan (Ashby & Jones, 1996).
Ultimately, even with different compositions of monomers selected for their favorable response to heating, curing dental polymers in commercial microwaves cannot provide a complete solution. Commercial microwaves are universally designed so that their magnetrons cycle on and of instead of emitting a constant flow of microwave energy. For this...
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