Negative Pressure Irrigation Dynamics between Two Needle Designs using Computational Fluid Dynamics

Objective: This study aimed to investigate the irrigation dynamics of the EndoVac and modified apical negative pressure (mANP) using Computational Fluid Dynamics (CFD) for application in endodontic irrigation.Methodology: A simulation of a prepared root canal (conical frustum) of 12 mm length with an apical diameter of 0.40 mm following Protaper F4 apical preparation was created using three-dimensional (3D) CAD software. 3D simulated aspiration needles (EndoVac, micropores needle) and (mANP, 30G flat open-ended needle) were also created. The irrigation dynamics were evaluated through transient CFD simulations. In addition, the irrigation dynamics of mANP were also assessed at three different needle depths of insertion.Results: The EndoVac and mANP streamlines pattern showed irrigants able to reach the apical end. Both needle designs demonstrated negative static apical pressure. The mANP using an open-ended needle design revealed a higher average WSS magnitude in all three different needle depths of insertion compared to the EndoVac.Conclusion: CFD analysis of the EndoVac and mANP revealed that different needle designs and needle depth insertion affect the irrigation dynamics pattern and magnitude in a simulated root canal. The open-ended needle design of mANP1 contributed to the higher WSS magnitude, discharge coefficient, and apical static pressure compared to the EndoVac.