Purpose: to determine if reusing ProTaper rotary instruments up to five times increases their separation incidence.
•N = 4652 (Treatment/Retreatment Cases)
•Treatments were done over a 17-month period by 5 endodontists
•Coronal flaring and glide path. WL determination. By EAL.
•In retreatment cases, removal of GP with solvent GG and hand files. •Instrumentation with ProTaper as per manufacturer instructions/
•When separation occurred, the following was recorded:
•Number of uses before failure (per tooth not canal)
Most highlighted Results:
•Total of 113 (2.4%) instruments separated
•Table 1 shows number of separation of each instrument Statistically significant increase in breakage of the F3 after the 5th use compared with other file
•Avoid reusing instruments more than 4 times (especially F