Objectives: This study aimed to compare the characteristics of laser-induced cavitation bubbles in different endodontic irrigants using a nanosecond neodymium-doped yttrium aluminum garnet (Nd:YAG) laser with far-field focused irradiation. Background: The nanosecond pulsed Nd:YAG laser is known to generate cavitation bubbles in water through laser-induced optical breakdown; however, its effects on different endodontic irrigating solutions remain unclear. Methods: A Q-switched Nd:YAG laser was used to evaluate eight endodontic irrigants, including distilled water, normal saline (0.9% NaCl), 17% ethylene diamine tetraacetic acid (EDTA), 2% chlorhexidine (CHX), and various sodium hypochlorite (NaOCl) solutions (0.5%, 1.0%, 3.0%, 5.25%). High-speed photography captured plasma and cavitation bubbles at 50 mJ/pulse and 30 mJ/pulse energy levels. The images of 10 consecutive bubbles were analyzed to assess bubble dynamics parameters, including diameter, area, duration, expansion velocity, and time to reach maximum dimensions. These parameters were statistically evaluated using the Kruskal–Wallis H test and Mann–Whitney U test. Results: Plasma generation occurred at both energy levels across all eight irrigants. The largest bubble diameter (4.83 mm) was recorded in 17% EDTA at 50 mJ/pulse, and the smallest (3.66 mm) was recorded in 0.5% NaOCl at 30 mJ/pulse. The highest bubble expansion velocity (19.31 mm/ms) was recorded in distilled water at 50 mJ/pulse, and the lowest (16.17 mm/ms) was recorded in 5.25% NaOCl at 50 mJ/pulse. The time to reach maximum bubble dimensions ranged from 0.17 ms to 0.24 ms. Conclusions : The nanosecond-pulsed Nd:YAG laser exhibited the ability to induce plasma formation and cavitation bubbles within the eight evaluated endodontic irrigants. This development establishes a fundamental basis for prospective applications in endodontic irrigation.
Bai et al. (Fri,) studied this question.