Why the Glide Path Matters

Rotary NiTi files are designed to shape a canal that has already been negotiated and pre-enlarged. When a rotary file is introduced into an unnegotiated or minimally negotiated canal, the tip engages unprepared dentin under torsional load — the primary mechanism of rotary file separation.

Minimum Glide Path Size

A minimum glide path of ISO size 15–20 at working length is generally recommended before introducing most rotary NiTi systems. Clinicians should follow the manufacturer’s recommendation for the specific system in use.

Glide Path Files

Dedicated glide path files are specifically designed for this purpose. They are more flexible and fracture-resistant than standard rotary files and are used at lower torque settings.

• Single-file glide path systems offer efficiency in straightforward cases.
• Sequential glide path systems provide more controlled enlargement in curved or calcified canals.
• Glide path files should be used after hand file negotiation to ISO 10, not as a substitute for it.

Curvature and Glide Path Integrity

In curved canals, the glide path should follow the natural curvature of the canal. Straightening the glide path leads to transportation and subsequent shaping errors that cannot be corrected.

Confirming the Glide Path

The glide path is confirmed when a size 15–20 hand file passes to working length with minimal resistance and can be withdrawn without binding. Rotary glide path files should then pass to working length smoothly before any shaping system is introduced.