Published online Mar 28, 2015. doi: 10.5412/wjsp.v5.i1.82
Peer-review started: September 28, 2014
First decision: November 27, 2014
Revised: December 25, 2014
Accepted: January 9, 2015
Article in press: January 12, 2015
Published online: March 28, 2015
Intracanal instrument fracture is an unpredictable and problematic occurrence that can prevent adequate cleaning and shaping procedures and influence the prognosis of endodontic treatment. The prevalence of instrument fracture is reported to range between 0.28% and 16.2%. This article presents an overview of the prevention and management of instruments fractured during endodontic therapy on the basis of literature retrieved from PubMed and selected journal searches. Instrument fracture occurs because of reduced metal fatigue and/or torsional resistance. The reasons include canal morphology and curvature, manufacturing processes and instrument design, instrument use times and technique, rotational speeds and operator experience. With the development of various equipment and techniques, most of the retained instrument separations can be removed safely. However, in canals without associated periapical disease not every fractured separation should be removed from difficult locations because of the increased risk for root perforation and fracture. In difficult cases, either retain or bypass the fragment in the root canal and ensure regular follow-up reviews. Fractured instruments retained in the presence of periapical disease reduce significantly the prognosis of endodontically treated teeth, indicating a greater need to attempt the removal or bypass of the file separations. Apical surgery might be required in some instances, emphasizing the importance of preventing instrument fracture.
Core tip: It is important to prevent the potential adverse consequences that may follow the fracture of endodontic instruments during root canal preparation. Nickel-titanium engine-driven rotary instruments are more prone to fracture than stainless steel hand instruments, but the risks may be reduced by avoiding multiple use of instruments, by careful operative techniques, in particular with small-sized instruments used in sharply curved root canals, by employing reciprocating hand-pieces and by selecting instruments having high torsional and fatigue resistance.