An in vitro model was used to test a hypothesis that the manual (apex locator) and motor-driven (apex locator-controlled handpiece) operating modes of 3 newly developed apex-locator-controlled handpiece devices (Dentaport ZX, Endomaster, XSmart Dual) give the same working length. The depth of penetration of the file into the root canal was measured using a digital micrometer and the distance of...