Fracture and deformation of ProTaper Next instruments after clinical use

Background The aim of this study was to evaluate the fracture and defects observed in ProTaper Next files discarded after a normal clinical use. Material and Methods 571 ProTaper Next rotary instruments were collected after clinical use from the clinic of endodontics over 12 months. The length of the files was measured using a digital caliper to determine any fracture, later all the files were evaluated under a stereomicroscope to observe defects such as unwinding, curving or fracture. The data obtained were analyzed using a chi-square and z test. Results 13.83% of the discarded files showed defects, the most frequent defect was fracture (7.53%). The highest rate of fracture was observed in…