SCREW-VENT IMPLANT AND PATENTED INTERNAL CONNECTION - 1986
1986 Screw-Vent Implant: Dr. Niznick introduced the Screw-Vent® implant in grade 1 commercially pure titanium [Figs. 1]. The Screw-Vent incorporated the same thread design and diameter (3.75 mm) as the Brånemark implant, but featured a 1.5 mm-deep internal hexagon with a threaded shaft below it. This patented connection provides the stability needed between the implant and the abutment to prevent screw loosening and thus minimizes long-term prosthetic complications.
It also allows screw-retained, two-piece abutments to interlock with the internal hexagon to prevent rotation, which made single tooth replacement a viable option in implant restorations. At the top of the internal hexagon, a lead-in bevel helps stabilize the abutment against lateral forces and reduces the chance of tissue being trapped in the joint, which could result in incomplete seating.
In 1992, the male hexagon of the mating abutment was tapered one and one-half degree to create frictional engagement with the internal hexagon of the implant. This patented friction-fit connection eliminates abutment tipping and wobble, which are major causes of screw loosening in other systems. Today, Paragon Implant Company offers the industry's only five-year guarantee against loose screws.