Evaluation of an ultrasonic technique to remove fractured rotary nickel-titanium endodontic instruments from root canals: an experimental study

By Ward J, Parashos P, and Messer H

Date: 02/2004
Journal: JOE

Purpose:

to illustrate 3 clinical cases in which removal of fractured instruments was attempted by adaptation of the ultrasonic technique described by Ruddle.

Clinical significance:

•An ultrasonic technique using CPR tips combined with the creation of a “staging platform” using Gates Glidden instruments and the use of the dental operating microscope was consistently successful at removing fractured rotary nickel-titanium instruments from narrow, curved root canals when some part of the fractured instrument segment was located in the straight portion of the canal.

•When the fractured instrument segment was located entirely around the curve, care must be taken because the success rate is significantly decreased and major canal damage may ensue.

case #1:

A 44-yr-old female was referred to the Endodontic Unit, for the orthograde endodontic retreatment of #16. the tooth was asymptomatic with the radiograph showing root-filling material in only the distobuccal canal. during retreatment procedure, 2.5 mm of the ProFile 25/.04 fractured at the curve in the apical third of the mesiobuccal canal. A check radiograph and magnification with the microscope showed the instrument segment was at the curve. by applying the technique (staging platform and use of ultrasonic tip), the fractured instrument could be successfully removed and the canals preparations and obturation was completed. At 12-month recall, the tooth was asymptomatic and showed no evidence of periapical pathosis.

Case #2:

A 54-yr-old male presented for the removal of a fractured instrument and continuation of endodontic treatment of #36. The radiograph showed a 2.5-mm segment of a (30/.06) ProFile orifice shaper at mid-root level in the mesiolingual canal. This tooth was asymptomatic with radiolucencies evident at the mesial and distal root apices. The fractured instrument segment could be seen with the microscope. The fractured segment was removed using the same technique and RCT completed.

Case#3:

A 26-yr-old female was referred for endodontic treatment of #36. This tooth presented with a buccal draining sinus and radiographically showed extensive apical external inflammatory root resorption. A ProFile 30/.04 instrument fragment, approximately 3.5 mm in length, was lodged in the apical third of the mesiolingual canal. the instruments could not be directly visualized under the microscope and its removal attempt was unsuccessful. instrumentation was done up to the instrument level and the tooth was dressed with Pulpdent® paste for 3 months. At 3-month follow up, the buccal sinus had healed and some radiographic resolution of the periapical radiolucencies was noted. the tooth was then obturated