Temperature dependence of the dynamic viscoelastic behavior of chemical- and light-cured composites.

The relationship of temperature to the viscoelastic properties of six composites, three light-cured and three chemical-cured, was studied, using constant dynamic loading over the narrow range of temperatures (20-60 degrees C) which can be encountered in the mouth. The parameters measured were: storage modulus G(1), loss modulus G(2), tan delta, quality factor Q, coefficient of decay alpha, and dynamic viscosity. It was found that the dynamic viscoelastic properties of the tested materials are temperature-dependent, but probably not to a clinically significant degree.

Resistance of cavity varnishes to solubility: a study in vitro.

Cavity varnishes are resinous materials used under permanent restorations to protect dental tissues from marginal leakage and harmful components of the restorative material. These materials are soluble in the fluids of the oral cavity. The purpose of this study was to investigate, in vitro, the degree of solubility of these materials in different solvents over a period of time, to obtain an idea of their effectiveness.