Evaluation of Removing Fractured Instruments From Root Canals

Objective:

Instrument fractures are the most common iatrogenic failure that occurs during clinical endodontic practice. Although various techniques have been developed, there is no standardized procedure for safe and succesful management of separated instruments in the root canals. The aim of the present study was to evaluate the success of methods that can be used in the retrieval of seperated instruments from different levels in curved and straight canals.

Methods:

Fractured instrument fragments were removed from the coronal, middle and apical thirds of the mesial canals of extracted mandibular molars(n=30) and anterior teeth(n=60). The first protocol for removal of fractured instruments from curved canals was creating a staging platform around the coronal aspect of the instrument and loosen the instrument by using the ultrasonic tips with direct visualization through a dental operating microscope. The second tecnique was using conventional tecniques with K files. In straight canals Masseran Kit was used additional to these techniques. The success of instrument removal in relation to the tehnique used and the location of fragment were determined. The successfull treatment was defined as removal or complete bypassing of the fragments.

Results:

The overall rate of success in removing or bypassing the broken instruments in curved canals was 93,3 % when ultrasonic tips are used under the microscope, 66,6 % when only conventional methods are used. In straight canals, the success rate was 47,6 % with MasserannKit, 95,2 % with ultrasonics and 80,9 % with conventional methods. Fragments located coronal one third of the root in curved and straight canals were removed completely in all techniques.

Conclusion:

The use of ultrasonic tips with direct visualization through a dental operating microscope is the most succesful technique for retrieval of fractured instruments from root canals.