Friday 3 June 2011

APEX LOCATORS ( ROOT ZX)

The use of electronic devices to determine the WL was proposed first by Custer  in 1918, and the first EAL(electronic apex locator),was developed after Suzuki’s investigation of the electrical resistance properties of oral tissues. The first generation of EAL was resistance, based whereas the second generation was based on impedance. The main shortcoming of both types ,which corresponded to poor accuracy with electrolytes.

This  was overcome by the introduction of third-generation apex locators, such as the Root ZX (J.Morita Corp Tokyo, Japan). The Root ZX uses the “ratio” method to measure the root canal length. This method involves the measurement of impedance values at two frequencies (8 KHz and 0.4 KHz) simultaneously and the calculation of a quotient that expresses the position of the file tip in the canal . The Root ZX apex locator is considered to be the gold standard against which newer EALs are evaluated .
                                                   
                                                      REF: JOE Vohme 37, Number 5, May 2011

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