EM Observations and Differential Scanning Calorimetric tudies of New and Sterilized Nickel-Titanium Rotary ndodontic Instruments

f bstract canning electron microscopy (SEM) and differential canning calorimetric (DSC) studies were utilized to nvestigate surface and microstructure of two brands of otary nickel-titanium (NiTi) endodontic instruments, in he as-received condition and after subjection to 1, 6, nd 11 sterilization cycles. A total of 66 ProFile (n 3) and Flexmaster (n 33) files were examined. SEM bservations indicated the presence of surface imperections and adherent material in all new and sterilized nstruments and an increase in surface roughness of the nstruments that underwent multiple sterilizations. DSC easurements showed that the specimens of both rands, in the as-received condition and after 11 sterlizations, were completely austenite in the oral envionment temperature, suggesting that they are capable f superelastic behavior in appropriate clinical onditions. (J Endod 2006;32:675–679)