title: Evaluation of diamond-coated ultrasonic instruments for root-end preparation.
abstract: Ultrasonic instrumentation has been associated with cracking of the dentin in the area of the root-end preparation. The purpose of this study was to evaluate root-end preparations for cracking and to describe cavosurface morphology after the use of diamond-coated instruments. Forty teeth were inspected for intradentin cracks, incomplete canal cracks, and complete canal cracks before and after preparation with a stainless steel CT-5 ultrasonic instrument and again after root-end preparation with an S12D/90 degrees diamond-coated instrument. Six teeth had polyvinylsiloxane impressions taken of the root ends after preparation with the CT-5 and again after preparation with the diamond-coated instrument. Replicas were made, split, sputter-coated, and inspected using the scanning electron microscope. This study indicates that use of the diamond-coated instrument for root-end preparation does not result in significant root-end cracking and that it can remove cracks created by a prior instrument's use. The use of the diamond-coated instrument resulted in a heavily abraded, debris-covered cavosurface that may affect the apical seal.
authors.affiliation: Department of Endodontology, Oregon Health Sciences University School of Dentistry, Portland 97201, USA.
authors.forename: P D
authors.initials: PD
authors.lastname: Brent
authors.forename: L A
authors.initials: LA
authors.lastname: Morgan
authors.forename: J G
authors.initials: JG
authors.lastname: Marshall
authors.forename: J C
authors.initials: JC
authors.lastname: Baumgartner
mesh_terms: D000704:Analysis of Variance; D020099:Coated Materials, Biocompatible; D003762:Dental Instruments; D003804:Dentin / Q000293:injuries / Q000648:ultrastructure; D018130:Diamond; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D006801:Humans; D008855:Microscopy, Electron, Scanning; D012184:Retrograde Obturation / Q000379:methods*; D018915:Root Canal Preparation / Q000295:instrumentation*; D013499:Surface Properties; D014082:Tooth Fractures / Q000517:prevention & control*; D014092:Tooth Root / Q000293:injuries; D014464:Ultrasonic Therapy / Q000295:instrumentation*
chemical_list: D020099:Coated Materials, Biocompatible; D018130:Diamond