FGF18 and osteoarthritis: These results suggest that TMJ intra-articular injections of FGF18 increase cartilage thickness, proteoglycan distribution, proliferation of chondroprogenitors and decrease markers for osteoarthritis in the fibrocartilage of TMJ after experimental degeneration, postulating FGF18 as a powerful growth factor for the healing of TMJ fibrocartilage.