title: Evaluation of cracks associated with ultrasonic root-end preparation.
abstract: The purpose of this study was to evaluate the integrity of resected root-end surfaces of extracted human teeth after using ultrasonic tips at low or high frequencies for root-end preparation. Thirty bilaterally matched pairs of single-rooted human teeth had root-end resections using a low-speed diamond saw and were examined for root-end cracks. The matched pairs of teeth were then divided into two experimental groups, with one member of each pair being placed in each group. In group 1, root-end preparations were made with an ultrasonic tip on the lowest frequency setting. The preparations in group 2 were done on the highest power setting. Two investigators again examined the resected root-ends using a stereomicroscope at x20 to x63 and recorded the numbers, types, and location of the cracks. Three types of cracks were observed: canal cracks, intradentin cracks, and cemental cracks. There were significantly more root-ends with cracks after ultrasonic root-end preparation than after root-end resection only. In root-ends that had any cracks, significantly more canal cracks per root occurred when the ultrasonic tip was used on the high-frequency setting for root-end preparation than when the ultrasonic tip was used on the low power setting.
authors.affiliation: School of Dentistry, Oregon Health Sciences, University School of Dentistry, Portland 97201, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Layton
authors.forename: J G
authors.initials: JG
authors.lastname: Marshall
authors.forename: L A
authors.initials: LA
authors.lastname: Morgan
authors.forename: J C
authors.initials: JC
authors.lastname: Baumgartner
mesh_terms: D001047:Apicoectomy / Q000009:adverse effects* / Q000295:instrumentation*; D005069:Evaluation Studies as Topic; D006801:Humans; D014082:Tooth Fractures / Q000209:etiology* / Q000473:pathology; D014464:Ultrasonic Therapy / Q000009:adverse effects*