Irrigant flow characteristics in the root canal with internal root resorption: a computational fluid dynamics...

Area of Science:

• Endodontics
• Biomaterials Science
• Computational Fluid Dynamics

Background:

• Internal root resorption presents challenges for effective root canal disinfection.
• Traditional irrigation methods may struggle to adequately clean complex root canal anatomy.

Purpose of the Study:

• To evaluate the irrigant dynamics of different needle designs and ultrasonic irrigation in root canals with internal root resorption.
• To analyze the influence of needle insertion depth on shear stress and irrigant extension.

Main Methods:

• Utilized a computational fluid dynamics (CFD) model based on micro-CT scans of a mandibular premolar with internal root resorption.
• Simulated syringe irrigation with side-vented, double side-vented, and notched needles, alongside ultrasonic irrigation.
• Varied needle and ultrasonic tip positions at 2, 4, and 5 mm from the working length.

Main Results:

• Irrigant extension increased towards the working length (2-5 mm).
• Ultrasonic irrigation consistently produced higher shear stress values compared to needle designs.
• Coronal needle positioning enhanced shear stress distribution on resorption cavity walls.
• Needle position and type significantly affected irrigant residence time within the canal.

Conclusions:

• Ultrasonic irrigation demonstrates superior efficacy in generating shear stress for root canal cleaning.
• Needle design and precise insertion depth are critical factors influencing irrigant delivery and effectiveness in resorptive cavities.
• CFD modeling provides valuable insights into optimizing irrigation strategies for complex root canal anatomies.