Objective: To investigate the tissue dissolution efficacy of different concentrations of sodium hypochlorite (NaOCl) using the GentleWave^® technology (GW) and compare it with that of passive ultrasonic irrigation. This study will provide a novel in vitro model used to evaluate the tissue dissolution efficacy of different concentrations of NaOCl using the GentleWave^® procedure. Materials and Methods: Palatal bovine tissue was standardized by weight at 70–75 mg (average of 74.4 mg). The samples were divided into three groups of n = 10, Group 1: GW + 0.5% NaOCl, Group 2: GW + 3% NaOCl, and Group 3: ultrasonic group (US) + 6% NaOCl, and a control group of n = 2 with GW + H₂O. A specialized CleanFlow instrument was manufactured for the GW groups. For the US group, an apparatus was developed to allow the tissue to be in close contact with a freely operating ultrasonic tip. Each group was operated with its specific irrigants and dissolution times were obtained unless the samples were not visually dissolved within 5 min, and the dissolution rates were calculated. Dissolution times and rates were analyzed using univariate analysis of variance followed by a t-test. Results: The GW groups with 0.5% and 3% NaOCl dissolved entire tissue samples within 5 min and had average dissolution times of 227.5 s (Group 1) and 81.5 s (Group 2). GW with water had a higher tissue dissolution rate than ultrasonics with 6% NaOCl. Conclusions: The GentleWave^® using a lower concentration of NaOCl showed a similar clinical efficacy of dissolving tissues but displayed a significantly faster rate when compared with passive ultrasonic agitation.

Background: Pulp tissue debridement and the eradication of microorganisms from an infected root canal system before obturation is a primary focus of endodontic treatment and the best predictor for the long-term success of endodontic treatment. Objective: The purpose of this in vitro laboratory study was to evaluate pulp tissue debridement and the disinfection efficacy of two different Er;Cr:YSGG laser units, with a 2790 nm wavelength, compared to ultrasonic-activated irrigation (UAI) in root canals infected with Enterococcus faecalis. Methods: Human non-infected mandibular first molars were extracted, disinfected, and cultured with Enterococcus faecalis. Different types of Er;Cr:YSGG laser irrigation and UAI were performed according to the manufacturers’ protocols. The teeth were then processed for bacteriological and SEM analyses. Results: The different laser-activated irrigation protocols showed multiple areas of remaining bacteria, biofilm, tissue, and thermal ablation. The laser fiber tips also displayed significant tip degradation after use, which might affect efficacy. Conclusions: In this in vitro study, laser-activated irrigation using Er;Cr:YSGG technology and UAI were inefficient in eliminating pulp tissue from difficult-to-reach areas and Enterococcus faecalis from infected root canals.