Effect of psychological stress on orthodontic tooth movement in rats

The purpose of this study was to investigate the effect of psychological stress on orthodontic tooth movement in Wistar rats. Forty-eight female ten-week old Wistar rats with an average weight of 188 ±12 gr were selected and randomly divided into two experimental and control groups. The experimental group received crowded environment-induced and cat odour stresses 4 weeks before spring insertion. On the 29th day in both groups, maxillary incisors were moved by the insertion of springs and exactly after 7 days, 9 rats from each group and after 14 days the remaining rats were sacrificed. Then the mesioincisal distance between maxillary incisors was measured. Afterwards, histological sections were prepared to count osteoclasts under a light microscope. The data on the extent of orthodontic tooth movement and the number of osteoclasts were analyzed by independent sample t-test. The results indicated that on the 7th day after spring placement the orthodontic tooth movement was significantly higher in the control group compared to the experimental group (p