MEASUREMENT OF THE ELECTRIC CONDUCTIVITY OF DENTAL CEMENT

II. VALUES FOR SPECIMENS EXPOSED TO MOISTURE

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

While previous tests showed zinc phosphate cement to be an effective electric insulator when maintained in a dry condition, this investigation has indicated that its insulating ability is questionable if the cement is exposed to moisture. The resistance pattern of wet cells is entirely different from that of dry cells.

The resistance of the cement was found to be a function of the contact area; the larger the area, the less was the resistance. However, the variation in surface area which occurs in the clinical restoration probably does not significantly alter the insulating characteristics of the cement.

The resistance varied in respect to the temperature at which the cell was maintained. Temperature fluctuation during the investigation was not, however, great enough to alter materially the values observed.