Purpose: to compare the cleanliness and parallelism of root end preparations prepared by ultrasonic tips with those prepared by burs.
N= 20 anterior teeth
•20 anterior teeth from human cadavers were instrumented and obturated with gutta-percha and sealer
•A full-thickness flap was raised, the apices of the roots were exposed and resected with a fissure bur.
•Group 1 (US): 10 root end cavities were prepared using the Carr ultrasonic surgical tips.
•Group 2 (Burs): 10 root end cavities were prepared by a micro-head slow-speed handpiece and a #33 1/2 inverted cone bur with water irrigation. •One tooth was pulpally extripated, extracted, and sectioned to be used as a control.
•The teeth were extracted, sectioned longitudinally and examined under the scanning electron microscope (SEM) for cleanliness of the cavities and their directions in relationship to the root canal systems
Most highlighted Results:
•The ultrasonic cavities produced more parallel walls and deeper depths for retention.
•The ultrasonic tips followed the direction of the canals more closely than those prepared by burs.
•SEM examination of the cavity walls showed presence of cleaner surfaces of root end cavities prepared by ultrasonic tips than those made with burs. •Burs did not follow direction of RCS and almost perforated the lingual surface of the tooth
Ultrasonic tips improved the ability to prepare cleaner, deeper root end preparations, and this could contribute to a higher success rate in surgical root canal therapy.