Q. How can I utilize ultrasonics to facilitate locating calcified canals?
A. Piezoelectric ultrasonics in conjunction with the ProUltra ultrasonic instruments (Dentsply Tulsa Dental) provide a breakthrough in exploring for and identifying calcified, aberrant or previously missed canals. Ultrasonic systems importantly eliminate the bulky head of the conventional handpiece which notoriously blocks light and obstructs vision. Ultrasonic instruments are used with a light touch in a brush-cutting manner to progressively sand away precise amounts of dentin. Microscopes and ultrasonic instruments have led to microsonic techniques that have significantly improved vision, control and safety when searching for difficult to find canals.
Specifically, the abrasively coated SINE tips or the ENDO-2 or 3 are the ultrasonic instruments of choice for troughing along grooves such as between the MB1 and MB2 orifices. Traditionally, clinicians have searched for the MB2 system within the groove off the MB1 orifice when in fact the MB2 is mesial to this groove, under the shelf of overlying dentin. This lip of dentin can be safely sanded away and easily eliminated with ultrasonic energy. Ultrasonic instruments can also be used to chase calcified canals that are receded and have pulled down and away from the pulpal floor. Further, the tip of an ultrasonic instrument may be used to vibrate and disintegrate a pulpal stone and is safer and more efficient than drilling or trying to remove them with spoons or excavators. For additional information, I also refer you to the Ruddle on Shape•Clean•Pack
DVD and/or the Ruddle on Retreatment
DVD "Disassembly & Missed Canals" as each have sections that clearly show a number of methods for finding canals.