title: Effects of ultrasonic root-end cavity preparation on the root apex.
abstract: 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. After photographs of the prepared root ends were taken, their resin replicas were prepared and examined with a scanning electron microscope. Photographs and scanning electron microscope photomicrographs were examined for the presence or absence of cracks. The results showed a significantly higher incidence of crack formation in the walls of root-end cavities prepared by ultrasonic tips compared with those made by the bur.
authors.affiliation: Department of Endodontics, Loma Linda University School of Dentistry, Calif., USA.
authors.forename: H R
authors.initials: HR
authors.lastname: Abedi
authors.forename: B L
authors.initials: BL
authors.lastname: Van Mierlo
authors.forename: P
authors.initials: P
authors.lastname: Wilder-Smith
authors.forename: M
authors.initials: M
authors.lastname: Torabinejad
mesh_terms: D000704:Analysis of Variance; D001047:Apicoectomy; D016009:Chi-Square Distribution; D003737:Dental Cavity Preparation / Q000009:adverse effects / Q000295:instrumentation*; D003786:Dental Pulp Cavity / Q000293:injuries* / Q000648:ultrastructure; D006801:Humans; D008855:Microscopy, Electron, Scanning; D016628:Replica Techniques; D014082:Tooth Fractures / Q000209:etiology; D014092:Tooth Root / Q000293:injuries; D014464:Ultrasonic Therapy / Q000009:adverse effects* / Q000295:instrumentation