Research progress in problem-solving nickel-titanium rotary instrument in endodontics.

Root canal therapy is the primary treatment method for pulpal and periapical diseases. Various advanced endodontic instruments for mechanical preparation have been marketed. The emergence of nickel-titanium rotary instruments has greatly improved the efficiency of root canal preparation. New demands have been put forward for nickel-titanium rotary instruments as a result of the deepening of clinicians' awareness of root canal anatomy system as well as the purpose and prognosis of root canal treatment. These clinical-oriented demands accelerate instrument reform and innovation. This work presents new marketed nickel-titanium systems and discusses the advantages and limitations of these systems and how they perform in terms of the efficiency and outcome of root canal preparation.