Fourth Generation Apex Locators

The Bingo 1020/ Ray-Pex 4 claims to be the fourth generation device and the unit uses two separate frequencies 400 Hz and 8kHz similar to the current third generation units.

Ray-pex 4 fourth generation device

The Elements Diagnostic Unit and Apex Locator was developed in 2003.

Apex locator

The device does not process the impedance information as a mathematical algorithm, but instead takes the resistance and capacitance measurements and compares them with a database to determine the distance to the apex of the root canal. It uses a composite waveform of two signals, 0.5 and 4 kHz, compared with the Root ZX at 8 and 0.4 kHz. The signals go through a digital-to-analogue converter to be converted into an analogue signal, which then goes through amplification and then to the patient circuit model which is assumed to be a resistor and capacitor in parallel. The feedback signal waveforms are then fed into a noise reduction circuit.