First-generation of electronic devi

First-generation of electronic devices, also known as resistance apex locators, measures the resistance using a DC adequate voltage supply. When the tip of the needle reaches the apex in the canal, the resistance value is 6.5 kilo-ohms (current 40 ìA). [6, 12] Such simple electronic devices are for example: Endodontic Meter II, Endodontic Meter S II, Endo Radar, Root Canal Meter