In vitro evaluation of smear layer removal by Er:YAG laser application with five different fiberoptic tip withdrawal techniques

Abstract

This study evaluated smear layer removal in apical and middle root thirds using five different fiberoptic tip withdrawal techniques. Thirty human canines were instrumented using 2.5% sodium hypochlorite, with a final irrigation of distilled water, and divided randomly in six different groups. Er:YAG laser was applied in five groups with a 50/28 fiberoptic tip (250 mJ input, 112 mJ output, 10 Hz, 1 mm from apex). Group 6 did not receive laser irradiation. Two pictures of each root canal (middle and apical thirds) were obtained under SEM and analyzed for the amount of smear layer. Results showed no statistical differences ( p>0.05) between treatments and significant differences ( p<0.01) between radicular thirds. It can be concluded that (1) all withdrawal techniques produced the same results on smear layer removal and (2) the middle third presented less smear layer than the apical third after Er:YAG laser irradiation.