Major observations of root canal instrument fractures and techniques for treatment and removal of endodontic instrument fragments: a systematic review

Abstract

Introduction: In the context of root canal endodontic treatments, fracture of instruments in the root canal during canal shaping is reported as one of the most common reasons for a negative prognosis. Nickel-titanium (Ni-Ti) instruments stand out. However, Ni-Ti instruments can fracture, with a prevalence of approximately 1.6% (0.7-7.4%). Special techniques to retrieve obstructing objects, such as ultrasonic instruments, hollow tubes with cyanoacrylate adhesive, trepanation techniques using an ultrasonic tip or a trepan bur, endo-extractors and welding with neodymium: yttrium-aluminum-perovskite (Nd: YAG) laser, and surgical techniques have been proposed. Objective: It was to develop a systematic review of the endodontic literature to externalize and discuss the main observations of fractures of root canal instruments, as well as to show the main techniques for treatment and removal of fragments of endodontic instruments. Methods: The PRISMA Platform systematic review rules were followed. The search was carried out from June to August 2024 in the Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: 93 articles were found, 34 articles were evaluated and 08 were included in this systematic review. Considering the Cochrane tool for risk of bias, the global assessment resulted in 32 studies with a high risk of bias and 27 studies that did not meet GRADE and AMSTAR-2. Most studies showed homogeneity in their results, with X2 =89.5% >50%. It was concluded that comprehensive cleaning of the root canal system is often impossible in the presence of a broken instrument. No consensus has been reached on a safe technique with a high success rate for removing broken instruments. Fracture of nickel-titanium (Ni-Ti) instruments during root canal instrumentation leads to compromised results in endodontic treatments. Thus, irradiation for a clinical procedure involving the use of a Neodymium: Yttrium-Aluminum-Perovskite (Nd: YAP) laser has shown good performance for removing fractured nickel-titanium files. Thus, fractured instruments can be removed by a variety of methods, such as good ultrasonic tips, microtubule devices, and hemostatic pliers/forceps. These techniques require qualified use of the operating microscope. Removing a fractured file is associated with considerable risk, and therefore the fragment must be circumvented. Removing fractured instruments can be expensive in terms of time and equipment. Thus, a cost-benefit analysis of the treatment must be considered before selecting a definitive therapy for the patient.