Even if EndoUltra is based on the same technology as teeth scaling devices (ultrasounds), principles are quite different. For scaling devices, the expected effect is a physical contact between the tip and the tooth in a dry environment. With EndoUltra, the active effect is due to the propagation of ultrasounds in an aqueous medium, without any physical contact between the tip and the canal’s wall. The tip is a transducer and its main role is to conduct the ultrasounds from the generator into the liquid (irrigant). The frequency (40kHz) is not audible by human beings.