Er:YAG Laser Activation of Sodium Hypochlorite for Root Canal Soft Tissue Dissolution


  • Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.

Correspondence to: Dr. Katharina Kuhn, med. dent., Center of Dentistry, Department of Prosthetic Dentistry, Ulm University, 89081 Ulm, Germany.



Background and Objective

The aim of this in vitro study was to investigate the effect of Er:YAG laser irradiation on the ability of sodium hypochlorite (NaOCl) to dissolve soft tissue during endodontic procedures.

Materials and Methods

Two acrylic glass plates, each containing a semi-canal, were bolted together to form a complete canal. This geometry permitted one semi-canal to be filled with fine liver sausage of bovine origin dyed by methylene blue and the other with NaOCl (4.00–4.99% available chlorine; Sigma–Aldrich Corporation, St. Louis, MA), which was then activated by Er:YAG laser irradiation (KEY Laser 3; KaVo, Biberach, Germany) using a plain-ended fiber tip and a range of output energy and repetition rate. To achieve relatively low output energy from high input energy, the laser beam was attenuated by placing glass slides in the beam path. The resultant images acquired were analyzed using pixel-based analysis. Samples were statistically analyzed (two-way ANOVA, P < 0.05, univariate, bifactorial; IBM SPSS Statistics 19, SPSS Inc., Chicago, IL).


Both output energy and repetition rate significantly influenced the tissue dissolution ability of NaOCl (P < 0.05).


Within the limitations of this in vitro study, we conclude that laser activation of NaOCl at 200 mW output power leads to effective soft tissue dissolution. This finding can be of use to endodontists pursuing effective soft tissue dissolution from their irrigants. Lasers Surg. Med. 45:339–344, 2013. © 2013 Wiley Periodicals, Inc.