The effectiveness of two Er:YAG laser systems on root canal cleanliness: A Comparative Scanning of Electron Microscope study

Aim: To evaluate the cleaning ability of two different systems of Er:YAG laser endodontic probes and to compare them with conventional root canal treatment.
Materials and Methods: Forty five root canals from twenty eight extracted permanent human teeth were cleaned and shaped up to size 40 and 0.06 taper with crown down technique using Profile® rotary nickel titanium instrument under frequent irrigation with Dakins® solution. The root canals were randomly distributed in three groups of fifteen root canals each. Group C: Root canals finally flushed with EDTA 3 % (Tubulicid plus®) for one minute. Group O: Root canals finally irradiated with Er:YAG laser using (Opus 20®) with endodontic probe (RCLase™) for one minute. Group K: Root canals finally irradiated with Er:YAG laser using (KaVo KEY Laser® 3) with optical fiber plug for one minute. The roots were split longitudinally and prepared for scanning electron microscope (SEM). Each root canal was evaluated for debris and smear layer at the coronal, middle and apical thirds.
Results: Significantly less smear layer (P<0.05) was found in the apical third of laser treated root canals compared with the control group, but no significant difference was found between the two laser probe systems. No significant difference (P>0.05) regarding the amount of debris would be found between the three groups.
Conclusions: The use of laser seems to be more effective than conventional root canal treatment in removing smear layer in the apical third regardless the laser probe system.