Tooth tissue and organ regeneration using stem cells

Tooth loss or damage, such as that caused by dental caries and periodontal disease, can cause fundamental problems with oral functions. The development of regenerative therapy for tooth tissue repair and whole-tooth replacement is currently considered a novel treatment with the potential to fully recover tooth function. Several mesenchymal stem cell-like cell types have been identified in oral tissues. These cells are thought to be good candidate cell sources for tooth tissue regeneration therapies because they exhibit the ability to differentiate into tooth tissues in vitro and in vivo. Whole-tooth replacement therapy is regarded as an important model system for the development of the concept of organ regeneration. A novel three-dimensional i n vi tro cell manipulation method, designated as an organ germ method, has been developed to recapitulate organogenesis. This method involves cell compartmentalization between epithelial and mesenchymal cells at a high cell density to mimic the multicellular assembly and epithelialmesenchymal interactions. The bioengineered tooth germ generates a structurally correct tooth in vitro, and erupted successfully with correct tooth structure when transplanted into a tooth socket in the oral cavity. We could also generate a size-controlled bioengineered mature tooth unit composed of periodontal ligament and alveolar bone. The bioengineered tooth unit was successfully engrafted into an adult jaw through bone integration. These bioengineered teeth were able to perform physiological tooth functions such as mastication, periodontal ligament function and response to noxious stimuli. Here, we review recent studies of tooth tissue-derived mesenchymal stem cells and the technologies underpinning tooth regenerative therapy. Rec.11/14/2012, Acc.12/10/2012, pp29-37