Behavior of mast cells in periodontal ligament associated with experimental tooth movement in rats

Orthodontic mechanical stress reduced the frequency of the appearance of mast cells stainable with toluidine blue in the periodontal ligament on both the pressure and tension sides of rat molar teeth. This effect was seen immediately after insertion of elastic bands between the first and second molars, and the greatest reduction in the number of mast cells stainable with toluidine blue was observed 15 min after insertion.