It is considered that self-curing resin will induce a little pulpal irritation, if mixing time is insufficient. So this study was designed to compare four different conditions between control group and three experimental groups. Canine teeth of 20 cats used, and class V cavities were prepared on maxillary canine of cats. Control group was filled with zone and other experimental groups were filled with zone after the application of the self-curing resin. Animals of the experimental and control group were sacrified at 3 days, 1, 2, 3, 4 weeks after the experiment. The finding lead to the following conclusions ; 1. Odontoblasts of first and third experimental groups were condensed irregularly and were changed at early stage, and reapir was delayed. 2. Odontoblasts of second experimental group were condensed slightly but, histologic repair was appeared at 4 weeks after the experiment 3. In all groups, the damaged odontoblastic cell layer were eventually disappeared at 4 weeks after the experiment.