Abstract : Nickel-titanium files can be used to prepare curved canals, but cannot penetrate the original canals if a previous dentist modified the root canal morphology. Negotiation, patency, and glide path before nickel-titanium instrumentation are important for success. This case report introduces a novel technique for negotiating root canals. Negotiation was performed by the novel technique using clockwise and counter-clockwise motion of the engine in three cases. This technique was effective in cases of a ledge in retreatment, a canal not easy to access, and challenging anatomy.
