Is Nd:YAG laser effective for inhibiting the growth of Candida albicans and Candida tropicalis?

Objective: Candida albicans and Candida tropicalis are the most common fungal species in humans. The present study aimed to investigate the effect of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser on inhibiting the growth of Candida albicans and Candida tropicalis in vitro. Methods: Candida albicans and Candida tropicalis species were cultured in sub-dextrose agar containing chloramphenicol and exposed to Nd:YAG laser (1064 nm). The laser was emitted at the pulse frequency of 1 Hz (1 pulse per second) for 7 or 13 seconds. At each pulse duration, the energies of 40, 60, 80, or 100 mJ were delivered to microbial plates. After radiation, the number of colonies was counted and reported as colony-forming units per milliliter (CFU/mL). Results: There was a significant reduction in the number of Candida albicans and Candida tropicalis colonies after Nd:YAG laser radiation, compared to the control group (P 0.05). At the pulse duration of 7 seconds, there was a significant difference in the number of Candida albicans colonies between the pulse energy of 40 mJ with other pulse energies (P 0.05). At the pulse duration of 13 seconds, the energies of 80 mJ and 100 mJ were significantly more potent at killing Candida tropicalis than other pulse energies (P 0.05). Increasing the duration of irradiation from 7 to 13 seconds was effective at killing Candida species at most pulse energies (P 0.05). Conclusions: Nd:YAG laser is effective in inhibiting the growth of Candida species. Under the conditions of this study, the antifungal effect of Nd:YAG laser improved with increasing pulse energy and duration of laser irradiation.