instrumentfraktur

Instrumentfraktur is a term used in dentistry, especially endodontics, to describe the fracture of an endodontic instrument, such as a file or reamer, during root canal treatment. A fractured fragment may remain within the root canal and complicate cleaning, shaping, and obturation. The term appears in German-language literature as Instrumentenfraktur and in English as instrument fracture.

Causes include cyclic fatigue from bending in curved canals, torsional overload when an instrument binds, and design or manufacturing flaws. Reuse beyond the instrument’s intended lifespan and improper technique increase fracture risk. Nickel-titanium and stainless-steel instruments can fail in different patterns; rotary NiTi files are particularly prone to cyclic fatigue fractures.

Detection and management: Fragments are usually detected radiographically. Retrieval attempts use ultrasonic tips and specialized retrieval files or micro-forceps. If retrieval succeeds, the canal can be cleaned, shaped, and obturated. If not, alternatives include bypassing the fragment, surgical removal (apicoectomy), or extraction. In some asymptomatic cases, leaving the fragment in place may be considered when removal poses greater risk.

Prevention and prognosis: Prevention focuses on preserving instrument integrity with careful technique, glide paths, adherence to torque and speed limits, and avoiding reuse beyond recommended lifespans. Regular inspection for deformation and careful navigation of curved canals reduce risk. Reported incidence varies, generally ranging from under 1% to several percent, depending on instrument system and operator experience.