The clinical treatment of complicated root canal therapy with the aid of a dental operating microscope

Objectives: To evaluate the clinical application of the dental operating microscope (DOM) in the management of complicated root canal therapy. Methods: 345 teeth with 546 root canals which could not be successfully managed by conventional methods received therapy under the DOM with ultrasonic instruments by the same endodontists. The aetiology of the canals included calcification, broken instrument, missed canal and canal perforation. The teeth and canals successfully managed were then calculated. Results: 406 canals were successfully managed with a rate of 74.4%; 246 teeth were successfully managed with a rate of 71.3%. The rates in each category of the complicated root canals were: 74.0% for calcified canals, 72.3% for canals blocked by broken instruments, 82.5% for missed canals and 72.7% for canal perforations. Conclusions: The clinical application of the DOM is an effective way of managing complicated root canal therapy.