Purpose: To investigate the incidence and aetiology of file fracture as well as analysing recommended prevention protocols. Additionally, the effectiveness of alloy modifications in reducing the incidence of file fracture was considered.
Most highlighted Results:
-The bulk of the literature relating to instrument fracture is in vitro evidence, which limits its clinical relevance.
-The reported incidence of NiTi instrument fracture is similar to stainless-steel (SS) files (inconsistent methodologies hamper accurate comparison).
-NiTi instruments are reported to fail by torsional overload and/or flexural fatigue, with file fracture occurring principally in the apical third of the canal or with inappropriate use. (figure)
-A conflict of interest appears common in some studies with commercial representatives of certain systems also reporting on their benefits within the literature.
-Operator skill, manufacturer modifications (Table) and limiting file reuse have been demonstrated to be significant in reducing fracture incidence indicating the importance of a prevention strategy.