Computational analysis of sodium hypochlorite concentration impact on the mechanical efficacy of root canal irrigation dynamics

Objective: The objective of this study is to evaluate the impact of varying concentrations of sodium hypochlorite (NaOCl) solutions on the mechanical washing efficacy during root canal irrigation. The focus is on the fluid dynamics of sodium hypochlorite and its interaction with air bubbles, particularly assessing the effects on fluid viscosity, pressure, velocity and shear stress distribution along the canal wall. Methods: This study uses computational fluid dynamics (CFD) and finite element analysis (FEA) through Ansys-CFX software to simulate the root canal irrigation process. A two-phase flow model was employed, consisting of a liquid phase (NaOCl) and an air phase (air bubbles). Three different concentrations of sodium hypochlorite solutions (1.25%, 2.6% and 5.25%) were analyzed to observe their effects on key mechanical parameters during the irrigation process. Results: The simulation results demonstrated that variations in NaOCl concentration significantly affected fluid viscosity, pressure, velocity and shear stress along the canal walls. Higher concentrations of sodium hypochlorite solutions exhibited different flow dynamics, potentially enhancing the mechanical washing efficacy of root canal debridement. Conclusion: This study concludes that the concentration of sodium hypochlorite plays a crucial role in optimizing irrigation efficacy in root canal therapy. Based on the derived computational outcomes, practical recommendations were formulated to improve the cleaning process during endodontic procedures.