During curing of multifunctional methacrylate-based composites for dental restorations, strong structural changes, significantly affecting the final properties of the materials, are observed. In fact, the polymerization of thermoset matrices involves the transformation of a viscous liquid in a glass
Cure behaviour of visible light activated dental composites
โ Scribed by A. Maffezzoli; R. Terzi; L. Nicolais
- Publisher
- Springer
- Year
- 1995
- Tongue
- English
- Weight
- 602 KB
- Volume
- 6
- Category
- Article
- ISSN
- 0957-4530
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โฆ Synopsis
In this paper, the non-isothermal cure behaviour of a dental composite, activated by visible light, is described using a heat transfer model that, coupled with a reaction kinetic expression, is able to predict the temperature and the degree of reaction in the composite. The temperature and the degree of reaction profiles inside the composite are calculated, as a function of the cure time, taking into account the system geometry, the thermal diffusivity of the composite, and the resin reaction rate. Material properties, boundary and initial conditions and the kinetic behaviour are the input data of the heat transfer model. Once the degree of reaction is known, the glass transition temperature profiles across the thickness of the composite are calculated. Experimentally measured glass transition temperatures are used for the evaluation of an extinction coefficient capable of accounting for the effects of the light absorption through the thickness on the polymerization kinetics. Finally, the effects of the non-isothermal cure conditions on the application of these materials in dental restorations are discussed.
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