The ultrasonic technique is a nonrotary method of cutting dental hard tissue and restorative materials using piezo electric oscillations. The use of high magnification and proper illumination is essential with these instruments. A combination of ultrasonic instruments with the microscope has been termed microultrasonics.
Ultrasonic instruments are used to trough in searching for calcified canals, removal of obstructions from canals such as broken instruments and posts, and in endodontic microsurgery for root end preparations. Additionally, ultrasonic activation of a disinfectant solution in the root canal system yields best results in eliminating intracanal infection.