Development of a frequency-dependent-type apex locator with automatic compensation

Area of Science:

• Biomedical Engineering
• Endodontics
• Dental Materials

Background:

• Electronic apex locators (EALs) are crucial for root canal length measurement.
• Accuracy of conventional EALs is compromised by electrolytes used in treatments.
• Frequency-dependent EALs offer potential for improved accuracy.

Purpose of the Study:

• To develop a novel frequency-dependent EAL that minimizes electrolyte influence.
• To enhance the accuracy and reliability of root canal length measurements.
• To validate the performance of the new EAL in simulated clinical conditions.

Main Methods:

• Development of a new frequency-dependent EAL utilizing two specific frequencies (0.5 and 10 kHz).
• Measurement of impedance ratio and voltage difference to determine file position and fluid status.
• Implementation of a compensation mechanism based on voltage differences to correct for electrolyte effects.
• Experimental validation using a tooth model with common irrigating solutions (H2O2 and NaOCl).

Main Results:

• The selected frequencies (0.5 and 10 kHz) demonstrated superior performance over conventional frequencies.
• The impedance ratio accurately indicated the file's position within the root canal.
• The voltage difference effectively represented the root canal fluid's condition.
• Electrolyte-induced measurement errors were significantly reduced post-compensation: from +0.54 mm to +0.18 mm in H2O2 (p < 0.01) and from -0.33 mm to -0.01 mm in NaOCl (p < 0.01).

Conclusions:

• The developed frequency-dependent EAL significantly improves the accuracy of root canal length measurement.
• The novel approach effectively compensates for electrolyte interference, enhancing device reliability.
• This technology offers a more precise and convenient tool for endodontic procedures.