Retrieval of silver cones using different techniques.

Three different techniques of silver cone retrieval were investigated in 41 teeth containing 91 silver cones. The techniques used for retrieval were as follows: (i) hand instrumentation with files, spoon excavators and forceps; (ii) the automated Canal-Finder-System; (iii) ultrasonic devices. In all teeth, these techniques were used in the same sequence, starting with hand instrumentation, followed by the Canal-Finder-System, and ending with ultrasonic devices. Fifty-two of the 91 cones (57 per cent) could be removed with hand instruments. Of the remaining 39 cones, 19 were removed after using the Canal-Finder-System. An additional 10 cones could be removed after the use of ultrasonics. Two cones could only be bypassed by the Canal-Finder-System but were not removed with any of the techniques investigated in this study. Eight silver cones (9 per cent) could neither be bypassed nor removed. It was concluded that silver cone retrieval in more than half the cases could be performed easily with hand instruments, particularly spoon excavators. The automated Canal-Finder-System and ultrasonics proved to be helpful devices in many difficult cases, but did not guarantee success in every case.