Root canal cleanliness after preparation with different endodontic handpieces and hand instruments: a comparative SEM investigation.

The root canals of 150 extracted mandibular incisors were prepared to ISO 30 using eight different automated devices and hand instruments. The automated devices investigated were: Endoplaner, Excalibur, Ultrasonics (Piezon Master 400) with H2O2 (5%), or NaOCl (1%) as irrigants, Giromatic, Intra-Endo 3-LDSY, Canal Finder System, Canal Leader 2000, and Endolift. Hand instrumentation was performed using reamers and Hedstroem files. Fifteen teeth were instrumented with each device, cracked longitudinally, and investigated under the scanning electron microscope using five category scoring systems based on reference photographs for debris and smear layer. No preparation system or technique resulted in complete removal of smear layer and debris. The ultrasonic unit performed best followed by the Canal Leader 2000 and hand instrumentation, whereas the use of the Giromatic, the Endolift, the Canal Finder System, and the Intra-Endo-3-LDSY-handpiece resulted in insufficiently cleaned root canal walls.