Effects of cavity size on apoptosis-induction during pulp wound healing.

The effects of mechanical stress on apoptosis induction during pulp wound healing were examined. Mechanical stress cavities of two different sizes were prepared on individual rat molars, one twice the size of the other in the occlusocervical direction. The authors compared the distribution pattern and number of apoptotic cells of the two groups by terminal deoxynucleotidyl transferase-mediated labeling assay. At one hour and one day, significant differences were observed in the distribution patterns and number of apoptotic cells between the single-size and double-size group. Four days after injury, apoptosis still existed on pulp cells in the double-size group but not in the single-size group. At 14 days, no difference in the number of apoptotic cells between the two groups was observed. These results suggest that the magnitude of mechanical stress, such as cavity preparation, may modulate the induction of apoptosis during pulp wound healing.