An ultrasonic liquefaction endodontic system having a graspable hand piece (24) having a flow passageway therethrough. An ultrasonic energy generator (44) is secured to the hand piece (24). A flexible injection tube (38) is dimensioned for insertion into a tooth root canal. A source of flushing fluid (50) under pulsed pressure is connected to the hand piece (24) by which fluid pressure pulses having ultrasonic energy superimposed thereon are forced into a root canal.