Management of fractured instruments

Abstract

Instrument fracture during root canal preparation is frustrating. Instrument retrieval is even more frustrating and considered more challenging than other endodontic procedures. In general, when nickel titanium (NiTi) instruments fracture, they mostly fracture in the apical one-third or beyond a curve of the canal because of their superelasticity. In addition, the retained instrument fragment hinders further treatment, and thus the outcome of the treatment will be compromised. Although the success rates of instrument retrieval with ultrasonics alone are very high and in the range of 80 to 90 %, attempts at ultrasonic retrieval are deemed to be unpredictable in terms of time and dentine removal as there had been no standardized protocol for instrument retrieval in the past. Hence, in order to make removal of fractured instruments predictable, the instrument retrieval protocol should be performed in a two-step procedure consisting of an initial preparation phase followed by attempts at retrieval based on the individual treatment plan developed to address the specific diagnosis. It is essential to maintain as much tooth structure as possible to prevent root fracture and perforation during the preparation phase. Depending on the clinical scenario of each case, ultrasonics, loops, and NiTi rotary files can be used to remove fractured instruments during the retrieval phase. A recent study has indicated that instrument retrieval following this protocol was predictable and was significantly more successful as well as conservative in dentine removal than other traditional techniques. The prognosis of cases with retained fractured instruments in the canal may not be compromised when there is no preoperative periapical lesion associated with the root. © 2023 Elsevier B.V., All rights reserved.