A tooth implant system is provided, comprising a fixture, protrusions, and an abutment. The fixture has a top opening portion, a bottom closed portion, an inner surface portion, an outer surface portion, and a central hole portion surrounded by the inner surface portion. The plurality of protrusions are provided on the inner surface portion of the fixture at locations of substantially same heights from the bottom closed portion and with even circumferential intervals, and each of the plurality of protrusions comprises a vertical stop and a bottom edge. The abutment comprises an upper cylindrical portion, a middle connecting portion extending from the top cylindrical portion, and a lower engaging portion extending from the middle connecting portion. The lower engaging portion of the abutment is configured to be received into the central hole portion surrounded by the protrusions and engage with the protrusions.