Syringe irrigation in confluent canals: A sequential computational fluid dynamics assessment

Area of Science:

• Endodontics
• Dental Materials Science
• Biomedical Engineering

Background:

• Effective irrigation is crucial for root canal disinfection.
• Confluent canals present unique challenges for irrigant delivery and renewal.
• Syringe irrigation is a common method, but its efficacy in complex anatomy is debated.

Purpose of the Study:

• To evaluate the impact of root canal preparation, irrigation needle design, and placement depth on irrigant flow in confluent canals.
• To determine optimal parameters for efficient irrigant delivery and renewal in mesial roots of mandibular molars.

Main Methods:

• Micro-computed tomography (micro-CT) was used to scan prepared root canal models.
• Computational fluid dynamics (CFD) simulations assessed irrigation flow dynamics.
• Tested variables included ProTaper Next preparation sizes (X2, X3, X4), needle designs (side-vented, open-ended), and placement depths (5, 3, 2 mm from working length).

Main Results:

• Irrespective of needle type or depth, irrigant predominantly exited through the canal without the needle.
• Apical irrigant penetration and renewal were most effective with a 30G open-ended needle.
• The 30/.07v (ProTaper Next X3) preparation size demonstrated superior irrigant delivery with the optimal needle configuration.

Conclusions:

• Needle design and canal preparation significantly influence irrigant flow in confluent canals.
• An open-ended needle placed optimally, combined with a 30/.07v preparation, enhances apical irrigant exchange.
• These findings can inform improved endodontic irrigation protocols for complex root canal systems.