Efficacy of Electronic Foramen Locators in Controlling Root Canal Working Length during Rotary Instrumentation

Area of Science:

• Endodontics
• Dental Materials Science

Background:

• Accurate control of root canal working length is crucial for successful endodontic treatment.
• Electronic foramen locators (EFLs) are widely used to determine and maintain working length during instrumentation.
• Variations in EFL performance based on device and preparation level require further investigation.

Purpose of the Study:

• To evaluate the efficacy of two EFLs, Root ZX II (RZX) and Propex II (PRO), in controlling root canal working length during rotary instrumentation.
• To assess the reliability of these devices at different preparation levels (0.0 mm and -1.0 mm from the apical foramen).

Main Methods:

• Forty-eight human mandibular bicuspids were prepared using the Protaper rotary system (crown-down technique).
• EFLs (RZX in auto-reverse mode, PRO with MPAS-10R) monitored preparation at 0.0 mm and -1.0 mm levels.
• Post-preparation, file tip to apical foramen distance was measured after sectioning the apical third.

Main Results:

• At 0.0 mm, both RZX and PRO achieved 100% precision.
• At -1.0 mm, PRO showed 66.7% precision, while RZX showed 0.0% precision.
• RZX demonstrated significantly poorer results (0.96±0.11 mm) compared to PRO (0.43±0.23 mm) at -1.0 mm.

Conclusions:

• EFLs are precise in maintaining root canal working length when reaching the apical foramen.
• Both devices exhibited decreased precision when penetration was limited to -1.0 mm.
• The RZX AAR mode failed to maintain working length in all tested instances at -1.0 mm, highlighting potential reliability issues in specific scenarios.