Broken instrument removal--two cases.

This paper reports two clinical aids for the removal of broken instruments in root canals using a combination of hand instrumentation and ultrasonic devices. This technique is based on two phases: hand instrumentation with stainless-steel K-file instruments for bypassing the fragments, and K-files mounted on an ultrasonic handpiece for loosening and retrieval of the broken instruments. This method offers the following advantages: conservation of the remaining dentin wall of the root canal and elimination of the necessity for surgical treatment.