The implant has a cylindrical shaped median part (3) including self-tapping macro turns for allowing anchorage of the implant in a space created between a sinus membrane and a lower wall of a bone crest under sinus to give way for a newly formed bone. A frusto-conical shaped lower coronary part (4) includes self-tapping micro-turns to obtain a primary stability of the implant within the crest. A frusto-conical shaped upper coronary part (5) remains above a bone surface to prevent cortical residual resorption due to inflammatory reaction risks on level of an implant junction/cover screw.