TIME-TORQUE DIAGRAMS OF SELF-CUTTING OSTE OSYNTHESIS SCREWS OF VARIOUS LENGTHS IN FRACTURE (TEAR) TESTS IN ALUMINUM

Tapping screws of the Medicon system were checked for their mechanical strength by a time-torque curve and a new measurement system. To simu late a real situation three types of screws were applied. The predrill was 80% of the kernel diameter. The percentage of demolition was sign ificantly higher with longer screws because there was a typical tiltin g of screws in aluminium. All tested screws had double the minimum fra cture moment of 43 Ncm. Fracture of the screws occur-red at about trip le the torque of the maximal moment in the bones.