Effect of Nd:YAG Laser Irradiation on the Growth of Oral Biofilm

Nd:YAG laser irradiation with photobiomodulation setting demonstrated an antimicrobial effect with the greatest immediate reduction observed in <i>S. mutans</i>, achieving up to 85.4% reduction at the T2 settings. However, the laser's effectiveness diminished after 24 h. In single biofilm cultures, the highest reductions were noted for <i>C. albicans</i> and <i>S. mutans</i> at the T2 settings, with <i>C. albicans</i> achieving a 92.6 ± 3.3% reduction and <i>S. mutans</i> reaching a 94.3 ± 5.0% reduction. Overall, the T2 settings resulted in greater microbial reductions compared to T1, particularly in biofilm cultures, although the effectiveness varied depending on the microorganism and culture type. Laser irradiation, assessed immediately after using the crystal violet method, showed the strongest biofilm reduction for <i>Streptococcus mutans</i> in the T2 settings for both single-species and dual-species biofilms, with higher reductions observed in all the microbial samples at the T2 laser parameters (<i>p</i> < 0.05) Conclusion: The Nd:YAG laser using standard parameters typically applied for wound healing and analgesic effects significantly reduced the number of <i>Candida albicans</i>; <i>Candida glabrata</i>; and <i>Streptococcus mutans</i> strains.