Canal Walls Prepared by Two Rotary Techniques: A Scanning Electron Microscopic Study

Debris and smear layer were evaluated in canals prepared with either Lightspeed (LS) or ProFile (PF) rotary instruments. lrrigants used were tap water (group A) or alternating 5.25 % NaOCl and 17% EDTA (group B). Apical stops were prepared to size 52.5 in the LS and to size 6 (approximately IS0 size 36) in the PF techniques. The roots were split lon-gitudinally and examined at apical, middle and coronal levels for debris and the smear layer using a 5-step scale. Using only water, mean debris scores were similar for LS and PF. In contrast, with EDTNNaOCI, LS- and PF-prepared canals had similar debris scores at the apical and coronal lev-els, but there was a significant difference at the middle level. Mean smear layer scores were simila