ABSTRACT
Standardized cavities prepared in bovine teeth were restored with 4 types of filling materials, lathe-cut amalgam, spherical amalgam, silicate cement and composite resin. Restored teeth were immersed in 4 degrees C and 60 degrees C dye solution alternately by automatic device which makes it possible to change the immersion interval and number optionally. By means of measuring the depth of dye penetration, the marginal leakage induced during the thermal change was evaluated and the effects of the immersion interval and number were investigated. Results are as follows. 1) It is possible to obtain the marginal leakage quantitatively by means of measuring the depth of dye penetration. 2) The marginal leakage around various restorations are significantly influenced by the immersion interval and number. 3) The depth of dye penetration varies with types of filling materials. 4) The optimum immersion interval and number are 2 minutes and 60-120 times to evaluate the marginal leakage around various restorative materials.
