Efficacy of Er,Cr:YSGG Laser with Conical Tip Design in Smear Layer Removal at the Apical Third of Curved Root Canals

Abstract

This ex vivo study investigates the effectiveness of the new design of the tip of Er,Cr:YSGG laser (BIOLASETM) in removing the smear layer at the apical third of curved root canals. Eighty one freshly extracted intact single rooted human mandibular premolar teeth with 15° to 30o canal curvature were selected and decoronated at the level of the cementoenamel junction. The roots were divided into three main groups with 27 samples each. Group I—non-lased teeth, group II—teeth lased with plain tip and group III—teeth lased with conical tip. Each group was further divided into three subgroups of nine samples each with 2 ml of 17% (Ethylene diamine tetraacetic acid (EDTA), 2 ml of 2% chlorhexidine (CHX), 2 ml of 3% sodium hypochlorite (NaOCl) respectively. In all the three groups, canals were prepared with rotary nickel-titanium (NiTi) instruments to a working length 1 mm short of the apex to size F3, using ProTaper instruments. The fiber tips were placed into the appropriate irrigant solution in the root canal to a depth of 1 mm short of working length and then activated for 20 seconds. The teeth were split longitudinally and subjected to scanning electron microscopy (SEM) at 1000×. It can be concluded that to ensure complete removal of smear layer from the root canal system it may be prudent to activate EDTA with conical tip design of Er,Cr:YSGG laser during irrigation protocol in the curved root canals.