@article{oai:nagasaki-u.repo.nii.ac.jp:00009306,
 author = {Yozgatian, Joseph H. and Zeredo, Jorge L. and Hotokezaka, Hitoshi and Koga, Yoshiyuki and Toda, Kazuo and Yoshida, Noriaki},
 issue = {3},
 journal = {The Angle Orthodontist},
 month = {May},
 note = {Objective: To investigate by behavioral methods the relationship between emotional stress and pain during experimental tooth movement in rats.
Materials and Methods: Sixteen male Sprague-Dawley rats (210 to 250 g) were divided into two groups. The experimental group was treated with an active Ti-Ni appliance, and the control group received a passive appliance. A force of 20 gf was delivered by the active appliance between the maxillary first and second molars for 3 days. During this period the rat's behavior was evaluated eight times by means of open-field test and resistance-to-capture test. The specific parameters of animal activity were facial grooming, rearing, and locomotor activity, movement into the center of the open field, and response to capture.
Results: Parameters related to stress and pain were higher in the group carrying active appliance, compared to the group with a passive appliance. Statistically significant differences in stress-related behavior between control and experimental groups were found 8 hours after placing the appliance and were most evident on the second day. Pain-related behavior was significantly greater in the experimental group than in the control group at 24 hours.
Conclusions: The increase in emotional stress evoked by orthodontic tooth movement may precede the appearance of periodontal pain., The Angle Orthodontist, 78(3), pp.487-494; 2008},
 pages = {487--494},
 title = {Emotional Stress- and Pain-Related Behaviors Evoked by Experimental Tooth Movement},
 volume = {78},
 year = {2008}
}