The authors conducted a study of theoritical background and clinical application of the transitional denture with one subject at The Ohio State University, Graduate School. The applicability of this method is considered to be not so great, however, it is likely to be a advantageous way of approaching to the prospective denture patients with severe periodontal diseases. Especially, in this transitional denture technique, natural teeth are duplicated to reject the development of abnormal oral physiology and some effects occuring during edentulous period. As a result of the minimal surgery and protective measure of denture contouring and tissue conditioning, the transitional denture may show treatment effects to the dentrue surrounding tissues and basal seat tissues.