EFFECTS OF ULTRASONIC ROOT-END CAVITY PREPARATION ON THE ROOT APEX

This study determined the effect of bur and ultrasonic preparation on the root apex. After cleaning, shaping, and obturation of root canals of 47 single-rooted teeth and resection of their apexes were done, 24 root-end cavities were prepared with a bur, and the rest were prepared with ultrasonic tips attached to two different ultrasonic units. Afte r photographs of the prepared root ends were taken, their resin replic as were prepared and examined with a scanning electron microscope. Pho tographs and scanning electron microscope photomicrographs were examin ed for the presence or absence of cracks. The results showed a signifi cantly higher incidence of crack formation in the walls of root-end ca vities prepared by ultrasonic tips compared with those made by the bur .