Histological observations and OPG, RANKL expression in TMJ condylar cartilage. A. Representative sections of the condylar cartilage stained with H&E, TB, S.O and OPG, RANKL immunohistochemical staining. B. Comparison between the control and experimental groups in terms of condylar cartilage thickness, number of chondrocytes, extent of proteoglycan degraded areas, percentages of OPG- and RANKL-positive chondrocytes, and RANKL/OPG ratio in condylar cartilage (*p<0.05, **p<0.01, *** p<0.001). Two-way arrow: condylar cartilage thickness. Black arrow: the degraded cartilage areas.