This study aims to provide valuable insight into the irrigation in curved root canals with CFD method. Numerical simulation of the flow originated from a side-vented or an open-ended flat needle located in the prepared root canal with two different insertion depths was performed. The distribution of velocity, wall shear stress, apical pressure, and the detailed flow structures were all evaluated. The results show that both the side port of the side-vented needle and the curved portion of the target root canal tends to make circumferentially non-symmetric wall shear stress distribution and asymmetrical streamlines. However, the impact of the root-canal curvature variation on the flow pattern is apparent only when the open-ended flat needle was selected for irrigation or the needle was inserted into the curved part of the root canal. The insertion depth and the size of the gap between the outer surface of the needle and the root canal internal wall are critical to the apical pressure, except the former is simultaneously crucial for the micro-velocity zone decreasing. Overall, the optimal method for effective irrigation in a curved root canal is the side-vented needle with the same curvature to the root canal, deeper insertion, and reasonable gap size.

这项研究旨在为使用CFD方法的弯曲根管冲洗提供有价值的见解。对流动进行了数值模拟，该流动是由位于两个不同插入深度的预备根管中的侧面通气或开放式扁针产生的。评估了速度分布，壁面剪应力，顶压力以及详细的流动结构。结果表明，侧向穿刺针的侧端口和目标根管的弯曲部分都趋于使周向不对称的壁切应力分布和不对称的流线。然而，在流型根管曲率变化的影响是明显的，只有当选择了开放式的平针用于灌溉或针插入根管的弯曲部分。针的外表面和根管内壁之间的间隙的插入深度和间隙的大小对于顶压力至关重要，但前者同时对微速区域的减小至关重要。总的来说，在弯曲的根管中进行有效冲洗的最佳方法是侧通气针，其根管弯曲度相同，插入深度更深且间隙尺寸合理。