The Effect of ND: YAG Laser on Microorganisms Causing Dental Caries; In Vitro Study

Purpose: Streptococcus mutans and Lactobacilli are common microorganisms involved in the caries process, while Candida albicans and Streptococcus mutans are linked to higher rates of tooth decay and severe oropharyngeal conditions. Nd: YAG Lasers are utilized in both medicine and dentistry, enhancing dental enamel's acid resistance and harming pathogenic organisms. This study aims to assess the sensitivity of Candida albicans and Streptococcus mutans to Nd: YAG Laser treatment. Materials and Methods: Microorganisms were exposed to a Q-switched Nd: YAG Laser with a wavelength of 1064 nm, a beam diameter of 4 mm, and energy levels of 100 and 200 mJ for S. mutans, and 300 and 400 mJ for C. albicans. The laser emitted 100 and 200 pulses at a repetition frequency of 3 Hz. All data underwent statistical analysis. Results: Exposing the Streptococcus mutans and Candida albicans to neodymium dopped-yettrium aluminum garnet, resulted in a reduction in colony forming unit/milliliter (CFU/mL) with increased Laser energy and numbers of pulse with maximum reduction at 200 mJ – 200 pulse and 400 mJ – 200 pulse for Streptococcus mutans and Candida albicans, respectively. A statistically significant differences were shown in the bacterial number (CFU/mL) between each group when compared with the control group. A statistically significant differences were shown in the fungal number (CFU/mL) between each group in comparison with the control group except between 300mJ-100 pulse and control, there is no significant difference. Conclusion: ND: YAG exhibits antimicrobial effects against Candida albicans and Streptococcus mutans, with a stronger effect on the latter. Additionally, ND: YAG laser therapy promotes wound healing and reduces inflammation, making it an effective tool for managing oral infections. Its deep tissue penetration enables targeted treatment while minimizing harm to surrounding healthy cells. The principle of selective photothermolysis, where the laser energy is preferentially absorbed by pathogens, further enhances its efficacy against these microorganisms.