[An observation of the effects of rat's condylar cartilage after application of retractive force on the mandible].

The changes of histologic structure and matrix secreting of rat's condylar cartilage after application of upward retractive force to the mandible were investigated by means of histology and histochemistry. After the force application, the condylar cartilage became thinner, the amount of the cells in the germ zone decreased, and that in the transition and transform zone were extremely or even disappeared. Sometimes a calcification zone was discovered in the cartilage and some cells of the mature zone were embed in it. The amount of acid mucopolysaccharide in the matrix also decreased. The result indicated that the retractive force inhibited the proliferation and differentiation of condylar cartilage remarkedly. This was the mainly morphologic bases of the shorted mandible which as a result of the retractive force applied to the mandible.