砄bjective:To elucidate the effects of gradually induced occlusal disorder on the expression of TGF ?1 in temporomandibular condyle of monkey. Methods:In a monkey after extraction of right upper first molar and left lower first molar, a fixed orthodontic appliance was used to cause the adjacent teeth inclined to the space and to occlude with opposite in coordinately. Another monkey was used as the control.8 months later, the animals were sacrificed and bilateral temporomandibular condyles were examined with histologic and immunohistochemical methods.Results:In the animal with teeth extraction, degenerative changes were found in anterior medial part of condyles, the thickness of condylar cartilage decreased significantly, especially in the anterior parts of medial and central thirds, and also the intermediate part of medial third ( P