The effect of low level laser on number of Candida albicans colonies in-vitro: a new finding

BACKGROUND: Candida albicans is a commensal organism that causes a wide variety of diseases in humans. One of these diseases is oral candidiasis, which occurs at a high recurrence rate in spite of available treatments. The purpose of this study was to compare the effect of low-level laser therapy (LLLT) with the use of nystatin on in-vitro growth of Candida albicans. METHOD: We prepared two samples of Candida albicans at different concentrations: 10(4) viable cells/ml and 10(6) viable cells/ml. Specimens from each sample were divided into a control group, a nystatin-treated group, and a group treated with LLLT. The control group was cultured without any intervention. The second group was treated with nystatin and the solution was vibrated for 30 s or 60 s. The third group was irradiated with a gallium-aluminum-argon (Ga-Al-Ar) diode laser (Epic 10; Biolase Inc.)in continuous mode using a wavelength of 940 nm and a power of 1 W for 30 s or 60 s (38 J/cm(2) and 76 J/cm(2)). The specimens from the nystatin group and the LLLT group were cultured and the number of colony-forming units (CFU/ml) for each group was counted and compared. RESULTS: Nystatin completely eliminated the colonies (0 colonies) in all specimens. There was an increase in the number of colonies in the LLLT group for both cell concentrations at 30 s and at 60 s. However, this increase was statistically significant only for a concentration of 10(4) viable cells/ml at an exposure time of 30s. The increase in the concentration of 10(6) viable cells/ml at both 30 s and 60 s was statistically significant compared with the control group, although the highest number of colonies remained after an exposure time of 60s. CONCLUSION: LLLT led to an increase in the growth of Candida colonies. However, there was no significant difference related to the exposure time between the different cell concentrations.