Irrigation Dynamics of the TruNatomy Needle in a Minimally Prepared Root Canal: A Computational Fluid Dynamics Analysis

This study investigated the irrigation dynamics of the TruNatomy irrigation needle in a minimally shaped root canal using Computational Fluid Dynamics (CFD). The root canal geometry of an extracted maxillary first molar was reconstructed via micro-Computed Tomography (CT) scan, and the needle dimensions were obtained through stereomicroscopic analysis for Computer-Aided Design (CAD) modelling. The needle was virtually placed 1 mm short of the working length, and a prevalidated CFD model simulated the irrigation process. Irrigant penetration was confined to the needle tip, with a maximum velocity of 4.6 m/s. Wall shear stress of 340 Pa exceeded the threshold for effective debridement, and an apical pressure of 8.4 kPa was recorded at the apical wall. The TruNatomy needle produced uniform, low-magnitude wall shear stress along the lateral vent-facing canal walls, with limited apical irrigant exchange.