Abstract:

Objective

This research aimed to study the clinical effect of calcified root canals with ultrasonic instruments under dental operating microscope.

Methods

Forty seven calcified root canals of 43 teeth from 40 patients were negotiated with ultrasonic instruments under operating microscope， combined with EDTA and small size hand files， then shaped by ProTaper Nickel-titanium rotary instruments and filled with lateral or vertical condensation technique. The success rate and complications were recorded.

Results

Thirty seven calcified root canals were negotiated， enlarged and obturated， with a success rate of 78.7%. The success rate of anterior teeth and coronal portion of canal is higher than that of posterior teeth and apical portion of canal.Ten canals failed to be negotiated， two perforations occurred in a curved canal and the canal of a mandibular incisor. Six ultrasonic instruments were fractured and abandoned during the treatment.No vertical fracture was found.

Conclusiosns

The usage of ultrasonic instruments with dental operating microscope is proved to be effective in management of calcified root canals. Nevertheless，the use of the instruments in apical or curved portion of root canals is not encouraged.

Key words: Dental operating microscope, Ultrasonic instruments, Calcified root canal, Root canal therapy