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Bactericidal effects of the neodymium: YAG laser: In vitro study
Author(s) -
Schultz Robert J.,
Harvey Gregory P.,
Krishnamurthy Shanker,
Rodriguez Jose E.,
FernandezBeros Maria E.,
Cabello Felipe
Publication year - 1986
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/lsm.1900060505
Subject(s) - methylene blue , laser , pseudomonas aeruginosa , neodymium , irradiation , chemistry , escherichia coli , strain (injury) , staphylococcus aureus , microbiology and biotechnology , nd:yag laser , nuclear chemistry , materials science , bacteria , biology , optics , biochemistry , anatomy , physics , photocatalysis , nuclear physics , gene , genetics , catalysis
Abstract The effects of laser energy on three bacterial strains, Staphylococcus aureus, Escherichia coli , and Pseudomonas aeruginosa were studied utilizing the neodymium: YAG laser. Cell suspensions of each strain were divided into four groups. In group I, suspensions from each strain were exposed to laser energy densities of 555–3,333 J/cm 2 . In groups II and III, two artificial dyes, congo red or methylene blue, were added to the suspensions prior to lasing. In group IVa, no laser energy was used, and group IVb was used to measure the bactericidal thermal effects of the laser. It was concluded that: 1) Low dosages of laser energy exceeding 1,667 J/cm 2 resulted in a 2 to 8 log decline in the number of viable bacterial colonies in vitro. 2) Compared to the other two bacterial strains, P aeruginosa was the most senstive to YAG laser irradiation. 3) Addition of methylene blue, a dark‐colored dye, enhanced the bactericidal effects of the YAG laser as indicated by the significantly reduced viability of P aeruginosa after irradiation with 2,222 J/cm 2 .