Abstract : We have developed a new ultrasonic root canal preparation system which electronically monitors the location of the file tip during all instrumentation procedures.
For this electronic monitoring, the Root ZX was applied. Because the Root ZX has an effective filter circuit, the large spike noise of the ultrasonic unit can be cut out.
During enlargement of the canal, the ultrasonic vibration of the file can be stopped at any desired position on the meter display (auto-stop mechanism).
In extracted human tooth models which can electronically measure the canal length, the characteristic of the device was examined. Pre-and postoperative shapes of the root canals were evaluated using contact-micro-radiography (CMR).
The auto-stop mechanism worked correctly. Using a weak power and fine files, the straightening, ledge formation, separation of the files were minimal. It was clearly shown that this system minimized the danger of overinstrumentation and could be applied safely in clinics.
