Three-Dimensional Irrigant Flow–Induced Microstructural Changes in Root Dentin and Their Consequences on Post-Core Stress Distribution Under Functional Loading

Abstract

Background: The effectiveness of endodontic irrigation depends not only on chemical action but also on the three-dimensional (3D) hydrodynamics of irrigant flow within the root canal system. While advanced irrigation techniques enhance debris removal and disinfection, they may also induce microstructural alterations in root dentin, potentially influencing its mechanical behavior. These changes are clinically relevant in teeth restored with post-core systems, where stress distribution under functional loading plays a critical role in long-term survival.

Objective: This study investigates 3D irrigant flow–induced microstructural changes in root dentin and evaluates their consequences on post-core stress distribution under functional loading conditions.

Methods: A combined computational and imaging-based approach was employed. Three-dimensional computational fluid dynamics (CFD) modeling was used to simulate irrigant flow patterns and associated shear stresses within prepared root canals. Microstructural changes in dentin following irrigation were characterized using high-resolution micro-computed tomography (micro-CT), focusing on tubule morphology, surface erosion, and mineral density variations. These experimentally derived changes were incorporated into finite element models (FEM) of restored teeth with post-core systems to assess stress distribution under simulated masticatory loads.

Results: Regions exposed to higher irrigant velocity and wall shear stress demonstrated notable dentin microstructural alterations, including tubule enlargement and localized surface erosion. Finite element analysis revealed that these changes significantly influenced stress distribution, with increased stress concentrations observed at the post–dentin interface and in the cervical root region under functional loading.

Conclusion: Three-dimensional irrigant flow can induce measurable microstructural changes in root dentin that alter its biomechanical response when restored with post-core systems. Understanding the interplay between irrigant hydrodynamics, dentin integrity, and stress distribution may inform the optimization of irrigation protocols and restorative strategies to reduce fracture risk and improve clinical outcomes.