Clamping force

The initial clamping force, or preload, is created when the elastic recovery of a dental implant screw creates a force that pushes the abutment and the dental implant together. This occurs within the neck of the screw, in between the head of the screw and the first mating thread. When the clamping force is greater the external forces the screw should not loosen, however, this requires an accurate clamping force calculation. Although a clamping force calculator doesn’t exist, the force can be calculated if the coefficient of friction is known. Other factors that affect the calculation include screw stiffness and geometry, the rate of tightening, and the integrity of the hardware. Accurate preload is extremely important in implant dentistry and prevents the screw from coming loose by improving the fatigue strength of the screw and its locking effect. In cases of moderate lateral loads, 75% to 90% of the material elastic limit may be necessary to prevent the loosening of the screw.