Apex locators

Apex locator is an electrical device, used during endodontic treatment to determine the apical constriction and measure the working length of the canal.

It prevents under instrumentation which could leave pulp debris and infections behind and lead to further infection, also prevents over-instrumentation which could cause damage to the periapical tissues and cause patient discomfort.

Traditional working length determination using an x-ray involves errors that can lead to under-instrumentation or over-instrumentation.

Benefits of Electronic Apex Locator:

• Safe
• More accurate
• Fewer errors
• Less exposure to radiation
• Less procedural accidents

Generations of Digital Apex Locator:

• 1^st Generation: Resistance apex locator. Not effective in presence of pulp tissues or pus.
• 2^nd Generation: Impedance apex locator. It measures the impedance as the tip reaches near the periodontal ligament. Requires dry field for accuracy.
• 3^rd Generation: Frequency-dependent apex locator. The reactive component facilitates more for higher frequency than lower.
• 4^th Generation: Impedance characteristics using up to 5 frequencies were analyzed to determine the apical constrictions in dry canals.
• 5^th Generation: Modern apex locator with digital readout, graphic illustrations, and audible signal that works accurately with conductive fluids. Requires moist canals for more accuracy.

6^th Generation: Adaptive type with advantages of both 4^th & 5^th generations of apex locators. The device itself adapts the method of measurement depending on the humidity of the canal. (New Adaptive type of Measurement). Can give an accurate reading in canals with the presence of residual pulp, weeping canals, etc.