Antibacterial effects of Ga–As laser with toluiden blue on oral microorganism


Abdolmehdi Araghizadeh 1 , * , Mohammad Mehdi Fani 2 , Jamshid Kohanteb 3 , Leyla Khojastehpour 4

1 Assistant professor, Department of Community Medicine, Hormozgan University of Medical Sciences, Bandar Abbas, Iran.

2 Assistant Professor, Departments of Mouth Diseases, Shiraz University of Medical Sciences, Shiraz, Iran.

3 Microbiology, Shiraz University of Medical Sciences, Shiraz, Iran.

4 Mouth Radiology, Shiraz University of Medical Sciences, Shiraz, Iran.

How to Cite: Araghizadeh A, Fani M M, Kohanteb J, Khojastehpour L. Antibacterial effects of Ga–As laser with toluiden blue on oral microorganism, Hormozgan Med J. 2005 ; 9(2):e90345.


Hormozgan Medical Journal: 9 (2); e90345
Published Online: September 06, 2005
Article Type: Research Article
Received: May 10, 2005
Accepted: September 06, 2005


Introduction: Chemical antibacterial agents are increasingly being used in
prophylactic therapeutic regimes for oral and plaque–related diseases. As the
microorganism can be resistant to drugs so, there is a need for alternative
antibacterial approaches.
Bacteria can be sensitized to killing by light from low–power laser with chemical
photosensitizing agents such as TBO. The aim of this study was to investigate the
bacterial effect of Ga–As laser irradiation on oral microorganism.
Methods: The microorganisms evaluated in this in vitro study were: S.mutans,
Group A Beta Hemolytic streptococci, Neisseria, Bacteroides melaninogenicus.
Diphteroides, Lactobacilli, Fusobacterium fusiformis, S.aureus, S.epidermis &
candida albicans. The bactericidal effect was determined by the enumeration of
viable bacterial colonies. Time of irradiation was 20 mibns and frequency 3000
Hz with power 5 watt. Toluidine Blue is selected as a photosentisizer.
Results: Ga–As laser irradiation with energy density 1.8j/cm2 resulted in 31.3%
mean reduction in CFU number of S.mutans, 30.2% in Diphtheroid, 36.7% in
S.epiedermis, 19.2% in Neisseria, 37% in B.melaninogenicus, 32% in
Fusobacterium and 44.9% in candida albicans.
Conclusion: Ga–As low power laser can be used in preventive dentistry or in
treatment of oral lesions.



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