Etiology, Risk Factors, and Prevention of Endodontic Instrument Fracture

Background: Instrument fracture, an inevitable risk of root canal treatment (RCT), can be difficult to manage and can result in ineffective cleaning, shaping of the canals, and under filling.This may affect the prognosis and success of the treatment, lead to more complex treatment and even tooth loss.The aim of this review is to synthesize the literature on endodontic file separation to identify the mechanisms of fracture, its causes, risk factors, and techniques to reduce its incidence.Results: Risk factors of file separation include but are not limited to: low operator proficiency, root canal morphology, and instrumental technique.Recommendations to reduce risk of instrument fracture include: examining instruments prior to and after use; using lubrication during instrumentation; achieving straight line access; avoiding excessive apical force; practicing with a file system on extracted teeth prior to clinical use; implementing a crown down technique; adopting a limited use policy and replacing files used in complex root morphologies earlier; and avoid using rotary instruments in sharply curved or dilacerated canals. Conclusion:File separation is an unavoidable risk of RCT and it should always be discussed with patients during the informed consent process.Many risk factors involved in endodontic instrument separation are modifiable and small changes in operator technique can minimize risk of endodontic instrument fracture.Clinicians should be aware of these risk factors and best practices for preventing instrument fracture, and recognize and acknowledge their limitations in experience and skill and refer to more experienced practitioners when suitable.