Abstract: An oral fixture implant system for supporting a prosthetic denture structure in which fixture posts are implanted onto subperiosteal seats. A vertical projection shaft of the fixture post extends through the fibromucousal tissue and into the oral cavity. A fixture post collar is placed above the fixture post and a fixture retention bar with apertures corresponding to the fixture post locations is mounted over the collars allowing the upper portion of the fixture post projections to rise above the retention bar surface. The denture structure is fabricated with a grooved undersurface that accommodates the fixture retention bar and depressions in the groove fit over the tops of the fixture post shafts.