This is a dynamic time for researchers and clinicians devoted to optimizing periodontal/implant regenerative therapies. The explosion in understanding of regulators of cell function, coupled with tools that allow researchers to engineer cells so as to express specific factors, added to improved delivery systems for controlling release of cells/factors at a given site, now allows treatment modalities to be designed based on sound scientific data. Clearly, a first step is evaluating engineered cell types/delivery systems in in vitro and in vivo models. This would include examining their ability to enhance cell proliferation and/or mineral nodule formation and/or specific osteoblast- and cementoblast-associated genes in vitro and formation of new bone, new root surface mineral and a functional periodontal ligament region in vivo. Information gained from these studies should provide the foundation required for designing more predictable regenerative therapies when compared with thoseavailable at present.