The position of gingival soft tissues depends on the position and health of the underlying alveolar bone. Implant designs are evolving to maintain bone at predictable positions on the implant body through the development of stable and simplified prosthetic choices in abutment designs. The positioning of the restorative abutment deep inside the implant allows the abutment-implant joint to remain stable for a prolonged service life. With this stability, the titanium abutment allows the connective tissue and junctional epithelial seal ("biological width") to form and remain on the side of the abutment, rather than the side of the implant. Abutment joint stability plus well-defined implant surface topographies allow predictable implant rehabilitation in challenging situations. With the use of a mechanically and biologically stable joint interface, the prosthetic flexibility of a two-piece modular-style implant system allows the greatest flexibility for application in routine surgical and restorative implant dentistry.