Studies on Film Thickness, Solubility, and Marginal Leakage of Dental Cements

¹ Department of Dental Materials, Indiana University School of Dentistry, Indianapolis, Indiana

The film thickness, solubility, and sealing characteristics of a large group of commercial cementing and restorative materials were evaluated. Some of these were modified by the addition of amalgam alloy particles and cotton and glass fibers. Eugenol was incorporated in a mix of zinc phosphate cement.

An analysis of the data obtained from the 1200 tests resulted in the following conclusions:

1. The film thickness of all materials, with the test here employed, was less than the 40 µ generally considered to be the maximum limit acceptable for cementation.

2. The solubility of zinc phosphate cement was generally greater in dilute acetic acid than either silicate or zinc oxide-eugenol cements. The silicate cements, however, were more soluble in citric acid. Zinc oxide-eugenol was less soluble in water than were the other materials.

3. Generally, the sealing properties of zinc oxide-eugenol were superior to those of either silicate or zinc phosphate cement. For the most part, there was less marginal leakage of silicate restorations that of zinc phosphate. 4. The use of modifying agents with these materials had little or no effect on either solubility or leakage.