Bactericidal Effects of 2.94[mu]m and 1.67[mu]m Laser

• Published in: Bulletin of Tokyo Dental College Vol. 51; no. 4; p. 185
• Main Authors: Kukidome, Nobuyuki, Amagai, Tetsuya, Osuka, Keigo, Kato, Junji, Hirai, Yoshito, Kato, Tetsuo, Aida, Shigeo
• Format: Journal Article
• Language: English
• Published: Chiba Japan Science and Technology Agency 01.10.2010
• ISSN: 0040-8891

The bactericidal effects of lasers with wavelengths of 1.67 and 2.94μm on cariogenic Streptococcus mutans were investigated. Temperature during irradiation was also measured to determine the mechanism underlying the bactericidal effects of the lasers. An aliquot of 2μl cell suspension of S. mutans JC-2 strain was placed on anhydrous quartz or dentin plate, covering an area of approximately 5.0 mm in diameter to a depth of approximately 0.1 mm. Cell suspension was then irradiated at a power of 0.8 W (3.1 J/cm2) at a rate of 40 pps for 30 sec. After irradiation, the plate was put into a bottle containing PBS and vigorously voltated. Solution was serially diluted and inoculated on MS agar. After incubation anaerobically for 72 hr, colony forming units on the agar were counted. The experimental group, the number of bacteria decreased significantly compared to the control group under all conditions. No significant differences were observed in effect of wavelength or plate on bactericidal activity. In conclusion, laser irradiation at a wavelength of 1.67μm for 30 sec showed a bactericidal effect on S. mutans, suggesting that this wavelength is more useful than 2.94μm due to greater tissue penetration.