Evaluation of Apical Extrusion During Novel Er:YAG Laser-Activated Irrigation Modality.

Objective: To evaluate apical extrusion during a novel erbium-doped yttrium aluminum garnet (Er:YAG) laseractivated irrigation (LAI) modality. Background data: A novel double-pulse Er:YAG modality (AutoSWEEPS) was introduced recently, replacing a single laser pulse with two micropulses that are separated by a varying time delay (which is continuously "swept" between 300 and 600 lsec). Although the proposed method demonstrated increased efficacy, no data were yet available on extrusion. Methods: The extrusion was evaluated on simulated canals (n = 6) using particle imaging velocimetry. In the first two groups, the irrigation device was a syringe coupled to either a 30-G open-ended or side-vented needle, with flow rates of 1, 2, 5, and 15 mL/min. In the second two groups, irrigant activation was performed with an Er:YAG laser, using either a super-short pulse (SSP) or AutoSWEEPS modality. The pulse energies were 5, 10, 20, 30, and 40 mJ and the frequency was 10 Hz. Results: The measured extrusion was most prominent during the open-ended needle irrigation, followed by the vented needle irrigation. Compared with the conventional needle irrigation (CNI), all the studied LAI modalities resulted in *3-20 times less extrusion. The AutoSWEEPS modality induced the smallest extrusion rate, which was always <1.5mm3/sec and was also independent of the laser energy. Conclusions: Within the limitations of the study, our results demonstrate that the SSP and AutoSWEEPS laserassisted irrigation methods exhibited less extrusion in comparison with CNI methods. [ABSTRACT FROM AUTHOR]