Análise do desgaste promovido no ter o apical em canais simulados após preparo endod ntico com o Sistema K3 de conicidade .04

The authors analyzed the wear in apical third after K3 .04 System preparation. 12 sets of instruments were used and 12 simulated canals in transparent epoxy resin blocks with angles of curvature 20 and 40 degrees. Canals were photographed before preparation and after the utilization of instruments which prepared the apical stop: 30, 35, 40 e 45. The images were overposed in Adobe Photoshop program and the wear was measured in millimeters, in two points, 1 (A) and 5 (B) millimeters from the working length. By Variance Analysis the interaction existence was studied among these three factors: canal curvature, instrument caliber and curve location. In canals of 20 degrees, in both analyzed points, the wear mean promoted by instrument 40 and instrument 35 there was not statistically signifi cant. In canals of 40 degrees, in location A, there was not statistically signifi cant difference in the wear mean promoted by four different instruments. There was a deviation from the original trajectory to the outside the curve, in both analyzed points.