A micro-CT–integrated 3D simulation framework reveals fluid transport mechanisms and void dynamics in root canal fillings

Abstract

A micro-CT–integrated three-dimensional simulation framework (3D-SALAM) was developed to address the long-standing limitations of destructive, poorly reproducible leakage tests traditionally used to evaluate the sealing performance of root canal biomaterials. Despite decades of research, the long-term stability of root canal fillings remains uncertain because existing in vitro models fail to capture the complex, three-dimensional transport of fluids through micro-void networks. To bridge this methodological gap, the present study introduces and demonstrates 3D-SALAM—an innovative, non-destructive platform that integrates high-resolution micro-computed tomography with computational fluid dynamics to mechanistically characterise void geometry, connectivity, and fluid transport behaviour within obturated teeth. Micro-CT datasets (10 μm voxel size) from human single-rooted teeth were converted into numerical meshes for finite-volume simulations, systematically varying surface wettability (contact angle 25°–150°), injection velocity, and applied pressure. These simulations are presented as a proof-of-concept application of the workflow, illustrating how hydrophilic surfaces achieved up to 92% void saturation with less than 10% trapped air, while hydrophobic domains retained over 25%. Medium injection velocities produced optimal filling efficiency by balancing capillary and viscous forces, and applied pressure accelerated transport but induced pronounced local concentration gradients. This proof-of-concept study demonstrates that 3D-SALAM enables reproducible, quantitative, and mechanistic mapping of fluid dynamics in complex biomaterial architectures. Beyond characterising initial obturation quality, this approach provides a methodological foundation for longitudinal evaluation of material degradation, interfacial stability, and fluid-mediated transport phenomena. The framework’s adaptability also extends its relevance to a wide range of porous and composite biomaterials in regenerative medicine and biomedical engineering, where void connectivity and capillary behaviour critically influence long-term performance.