Brent P D, Morgan L A, Marshall J G, Baumgartner J C
Department of Endodontology, Oregon Health Sciences University School of Dentistry, Portland 97201, USA.
J Endod. 1999 Oct;25(10):672-5. doi: 10.1016/S0099-2399(99)80353-7.
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.
