Stem cell biology, an emerging field of research, provides promising methods in vitro as well as in vivo in animal models which make speculation about a future application in human dentistry reasonable. The objective of this study was to review the literature of stem cell research concerning fields relevant for dentistry. In dentistry, different stem cells are discussed. Adult dental ectomesenchymal stem cells seem promising for future therapy. Human stem cells have been isolated from the dental pulp, exfoliated deciduous teeth, the periodontal ligament, the dental follicle and the dental papilla. Stem cell markers such as STRO-1 were used for the characterization and isolation of stem cells. Adult dental stem cells can differentiate into many dental components, such as dentin, periodontal ligament, cement and dental pulp tissue, but not into enamel.