EFFECT OF LOW INCIDENT ENERGY LEVELS OF INFRARED LASER IRRADIATION ON THE PROLIFERATION OF CANDIDA ALBICANS. PART II:

Abstract

This study was performed to investigate the bioactivation effects of low level laser therapy (LLLT) on the fungus, Candida albicans, during its short term cell cycle. The laser used was a pulsed GaAs semiconductor laser emitting at 904 nm with a peak power of 27 W. The pulsing frequency could be selected to give a range of average output powers. Samples were divided into 6 groups, five irradiated experimental groups and one unirradiated control. The five experimental groups were each irradiated with a different pulsing frequency and average power: 500 Hz, 1 mW; 1.5 kHz, 3 mW; 3 kHz, 6 mW; 6 kHz, 14 mW; and 10 kHz, 27 mW, respectively. All samples were irradiated for 1 minute once at the beginning and then at regular two-hourly intervals during the approximate 27 hours of the cell cycle of C. albicans, and the optical density of the culture was assessed by spectrophotometry every two hours as a marker of the degree of photoactivation of cell replication. The collected data were subjected to statistical analysis. It was found that there was no statistically significant difference between the control and any of the groups irradiated at the two-hourly interval.