Prolonged immobilization-induced stress delays alveolar bone healing. A histometric study in rats

The purpose of the present study was to investigate the effect of prolonged immobilizationinduced stress on reparative bone formation, using the rat alveolar healing as an experimental protocol. Stress was attained by immobilization for 2 hours a day, beginning three days before extraction of the upper right incisors and continuing until sacrifice. The stress condition was assayed on the basis of plasma corticosterone concentration (measured by doubleantibody radioimmunoassay), which increased by 2.5 to 4 times in rats submitted to immobilization. The volume density of neoformed bone filling the alveolar socket was quantified by a histometric differential pointcounting method 7 to 21 days following tooth extraction. Stress caused a significant delay in reparative bone increment, somewhat related to impairment of coagulum remission andlor organization