The use of Nickel-Titanium rotary instruments have been increasing in the last two
decades. But the probability of fracture is still the most important hindrance that confuse
the practitioners. And many clinicians claim that the removal process is
very difficult and
often irretrievable. When compared with stainless steel instruments, hence this study aims
to compare between the two types effect of endodontic instruments on the success of
microsonic technique in removing or bypassing it, and the degree of difficulty.
