[Effect of experimentally created occlusal disorders on the expression of estrogen in rat condylar cartilage].

OBJECTIVE:To investigate the effect of experimentally created occlusal disorders (ECOD) on the expression of estrogen in rat condylar cartilage. METHODS:The model of ECOD was created by moving right upper and left lower first molars anteriorly. The animals in ECOD were sacrificed at 2, 4, 6, 8 weeks later. In removed occlusal disorders group, the moved first molars were extracted at 6 weeks later, and the animals were sacrificed 2 weeks later. The expression of estrogen was detected by SABC technique of immunocytochemistry, and then was analyzed by the density of estrogen-positive chondrocytes. RESULTS:1) Estrogen was abundant in mature layer and hypertrophic layer of rat mandibular condylar cartilage. 2) In control group, the expression of estrogen decreased gradually from 6-week-old to 16-week-old. 3) In both childhood and puberty rats, the expression of estrogen in experiment group was significantly higher at 2 weeks after treatment, while no difference was found at 4, 6, 8 weeks after treatment. However, the expression in removed occlusal disorder group was higher than that in control group and 8 weeks of ECOD group. CONCLUSION:In rat condylar cartilage, the expression of estrogen de-creases with age. Induced by ECOD, the expression of estrogen increases in early stage of remodelling activity.