Galler KM, et al. - Researchers examined root canals of 90 extracted teeth of humans (prepared to size 40, .06 taper) to evaluate the penetration depths of endodontic irrigants into the dentinal tubules using different activation methods. They categorized the straight and round-shaped root canals into 6 groups and performed final irrigation with EDTA and sodium hypochlorite: (A) manual dynamic activation, (B) Ultrasonic, (C) Sonic, (D) PIPS (photon-induced photoacoustic streaming, (E) SWEEPS (shock-wave enhanced emission photoacoustic streaming) and (F) control without final irrigation or activation. Lowest penetration of dye into the dentinal tubules was recorded for the controls. They found greater penetration depths in the apical thirds for ultrasonic, sonic and laser-induced activation when compared to manual dynamic activation. A correlation was noted PIPS and deeper penetration of irrigants.