[Torque of endosseous dental screw type implants].

The success of osseous and oral implants is partially dependent on the design and on the mechanical way of insertion. The torque moments during manual and machine-insertion and the correlation between torque and design of the implants were topics of this paper. The experiments were separated in two parts using pork-ribs in vitro. The first experiment was done with manual and machine insertion of implants. The second trial dealt with machine overloading of correctly inserted implants. The cylindrical implants showed an initial insertion curve followed by a linear phase which ended in a peak when insertion depth was reached. The conical formed implants did not show an initial curve while being inserted but a steeper linear phase and a defined peak when reaching the insertion depth. The torque moments at deep insertion (normal drilling depth) differed about 80% to the torque moments at normal insertion. The torques of continual machine insertion are 15 to 20% lower than those of discontinual manual insertion. According to these findings the design parameters for an optimal enossal oral dental implant should be of a cylindrical form with step like design, a cylindrical neck and a self cutting function of the symmetrical thread in combination with a blunt implant tip.