Abstract: An implant abutment system uses a combination of an implant anchor, an abutment having a plurality of connection features for connecting to the implant, and a locking pin for locking the abutment into the implant. The implant anchor includes an axial bore on a superior end having inner surface features matching outer surface features of the inferior end of the abutment. The cooperative operation of these features prevents abutment rotation once the abutment is positioned within the implant and also provides indexability for angled abutments. Such anti-rotation features are accomplished with matching splines and flutes machined on the cooperative surfaces between the abutment exterior and the implant bore inner surface. The invention also provides a retention feature for locking the abutment into the implant consisting of a resilient segmented end having a retention surface positioned to match a cooperatively formed surface in the implant bore.