The field of TMJ tissue engineering is blossoming, a field that was onnce far behind orthopaedic tissue engineering is rapidly gaining ground. Both TMJ disc and TMJ condyle tissue engineering efforts present unique challenges and will ultimiately be necessary to regenerate TMJs for patients suffering form severe disorders. The TMJ disc is a fibrocartilaginous structure with complex attachments, where tensile mechanical integrity is a crucial design requirement. The TMJ condyle presents the challenge of engineering both bone and cartilage. Its cartilage is a fibrocartilage with four distinct zones, and the design requirement for mechanical integrity is the ability to resist compression and shear. We are focusing our efforts in all three areas of the tissue engineering triad: cell source, scaffold selection, and chemical signals. With regard to cell source, we are interested in comparing a traditional source of cartilage cells with an exciting new source in human umbilical cord matrix(HUCM) stem cells for engineering cartilage. The HUCM stem cells have shown promise in their ability to synthesize GAGs and collagen on poly(glycolic acid) scaffolds. Moreover, we have initial data to suggest that HUCM stem cells will be strong candidates for bone tissue engineering as well. Regarding scaffold selection, we are currently investigating new hydrogels and novel approaches to designing poly(lactic-co-glycolic acid) scaffolds. Our research in chemical signals has focused on the use of glucosamine, and on the use of proteglycans along with growth factors. Our results have suggested that glucosamine may have a beneficial effect on TMJ condylar cartilage cells in culture, and effective concentration ranges are currently being investigated