Abstract. Effective irrigation is a key component of chemomechanical root canal preparation. Conventional needle irrigation (CNI) delivers the solution, but its effectiveness is limited by complex canal anatomy, especially in the apical third, lateral canals and isthmuses. Irrigant activation aims to enhance fluid movement and contact with canal walls. The most studied methods are passive ultrasonic irrigation (PUI) and laser-activated irrigation (LAI), including photon-induced photoacoustic streaming (PIPS) and shock wave-enhanced emission photoacoustic streaming (SWEEPS).