[Effect of precurving of canal instruments on their cutting capacity].

The author investigated the surface morphology and the cutting capability of endodontic instruments. One-hundred sixty flexofiles and 160 flexoreamers of various size, of which 40 were pre-curved by hand, 40 using hemostatic tweezers, 40 others were curved with an instrument designed for that purpose, and 40 remained unbent as a sample group, were used in the test. They were tested with a special device to determine the cutting capability. A morphological analysis of the surface was also performed with a stereomicroscope. The conclusions drawn were that pre-curving with hemostatic tweezers reduces the cutting capability by 75% for the flexofiles and by 50% for the flexoreamers doing irreparable damage to the surface structure of the endodontic instruments.