The implant-abutment interface determines the lateral and rotational stability of the implant-abutment joint, which in turn determines the prosthetic stability of the implant supported restoration. IACs have progressed from early external hex connection to more advanced internal connections which are dominating the market today, but there is no solidifying evidence pointing to a single best connection type. The external hexagon is indicated for multiunit restoration. On the other hand, the internal hexagon and the morse cone are more favorable in single-unit restorations and aesthetic regions. The platform switching concept is adequate under reduced prosthetic space (mesiodistal) to preserve the crestal bone and the interdental papillae.