Dissolution of Bovine Palatal Tissue with Degassed Sodium Hypochlorite

Objective: To investigate the tissue dissolution efficacy of different concentrations of sodium hypochlorite (NaOCl) using the GentleWave (R) 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 (R) 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 (R) 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.