A denture retention system includes a denture, abutments and an implant connected to each abutment. The denture has an inner channel with a resilient liner and engaging caps in the inner channel that releasably retain the denture on the abutments. The engaging caps each have a cavity that receives the head of an abutment. The cavities are sized with longitudinal space for the heads of the abutments so that the denture rests on the gingival tissue while the abutments restricts movement of the denture away from the gingival tissue. The system can be used with large diameter or mini implants. The separate implant and abutment allow precise selection of the abutment height. The abutment has a spherical head with tool engageable flats for tightening the abutment onto the implant.