# Centering Ability and Canal Transportation of Nickel-Titanium (NiTi) Single-File Systems With and Without Glide Path in Extracted Natural Teeth: A Systematic Review and Meta-Analysis

## TL;DR

Preparing a glide path before using NiTi single-file systems improves canal shaping accuracy and reduces errors in root canals.

## Contribution

Demonstrates that glide path preparation enhances centering ability and reduces canal transportation in NiTi single-file systems.

## Key findings

- Glide path preparation reduces canal transportation in coronal, middle, and apical thirds (p<0.05).
- Centering ability is significantly higher with glide path preparation in NiTi single-file systems.
- Meta-analysis confirms lower canal transportation with glide path preparation.

## Abstract

Establishing an endodontic glide path is crucial for the preservation of tooth structure and helps to avert various iatrogenic errors, including perforations and instrument fracture. Whether the preparation of the glide path is required before shaping the canals is still debatable. This systematic review aims to assess the centering ability and canal transportation of single-file nickel-titanium (NiTi) instruments with and without glide path in extracted natural teeth. The review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. An electronic database search using PubMed, SCOPUS, EMBASE, Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), Cochrane Library, Google Scholar, and grey literature was performed from inception till August 2025 based on the inclusion and exclusion criteria, and the quality was assessed using the revised Quality Assessment Tool for In Vitro Studies (QUIN) risk of bias tool. Three articles were included for the qualitative synthesis, and two articles were included for the meta-analysis. The results stated that there is less canal transportation and an increased centering ratio in the coronal, middle, and apical third of the canal when glide path preparation was done (p<0.05). The current systematic review provides evidence suggesting that centering ability is significantly higher and canal transportation is significantly lower for NiTi single-file systems when used after glide path preparation as compared to instrumentation without glide path preparation.