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Published on: January 10, 2014
Emotional stress- and pain-related behaviors evoked by experimental tooth movement
Joseph H Yozgatian1, Jorge L Zeredo, Hitoshi Hotokezaka
1Division of Orthodontics and Dentofacial Orthopedics and Division of Integrative Sensory Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan. j.yozgatian@gmail.com
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.
