US Patent 7247020 Drill set for dental screw implant fixture with self-tap

A drill set for adjusting an implant hole for a self-tap dental screw implant fixture comprises with a diameter d2 at the point of a cutting blade equivalent to a diameter D3 of the tip end of the fixture, a diameter d1 at the back end of the blade equivalent to the maximum root diameter of a first male screw 1e or smaller, and a length l1 of the blade larger than the entire length L1 of the fixture 1, and the second drill 3 with a diameter d5 at the point of a tapered tip end cutting blade 3b equivalent to the diameter D3, and a diameter d3 at the back end of a tapered back end cutting blade 3a equivalent to the maximum root diameter of the first male screw 1e and smaller than the maximum crest diameter thereof, both the blades 3a, 3b forming two-step taper shape.