EFFECTS OF CLEANING, DISINFECTION, AND STERILIZATION PROCEDURES ON THE CUTTING EFFICIENCY OF ENDODONTIC FILES

The effects of various cleaning, chemical disinfection, and sterilizat ion procedures on the cutting efficiency of endodontic instruments Uni file (De Trey, Bois Colombes, France), (Flexofile Maillefer, Ballaigue s, Switzerland), and H-File (Maillefer)) were investigated. The cross- infection control treatment procedures investigated were as follows: c hemical disinfection - NaOCl (2.5%) for 12 and 48 h, and NH4 (5%) for 1 and 4 h; ultrasonic cleaning for 4 and 16 cycles of 15 min; and ster ilization methods with chemiclave for 5 and 10 cycles of 20 min, Poupi nel for 5 and 10 cycles of 120 min at 180 degrees C and glass beads fo r 10 and 40 cycles of 40 at 250 degrees C. Cutting efficiency was eval uated as the mass of Plexiglas cut per unit of energy expended by the instrument in microgram/Joule. The cutting efficiency decreased from 1 to 77%, depending on the file design and type of treatment procedures . Heat sterilization (Poupinel) did not modify the cutting efficiency of Unifile and Flexofile. The decrease in cutting efficiency was indep endent of frequency and duration of treatment procedures.