Abstract
 An in-vitro comparison between antimicrobial activity of nanosilver and chlorhexidine against Streptococus sanguis and Actinomyces viscosus
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 Dr. Sadeghi R.,1 Dr. Owlia P.,2 Dr. Rezvani MB.,3 Dr. Taleghani F., 1 Dr. Sharif F.4
 1 Assistant Professor, Department of Periodontology, School of Dentistry, Shahed University. Tehran, Iran.
 2 Professor, Department of Microbiology, School of Medicine, Shahed University. Tehran, Iran. 3 Assistant Professor, Department of Operative Dentistry, School of Dentistry, Shahed University. Tehran, Iran. 4 Dentist.
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 (Received 15 March, 2011 Accepted 29 June, 2011)
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 Abstract
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Background and Aim: The antimicrobial activity of silver nanoparticles has been investigated in medical fields in recent years, but its effect on dental plaque micro-organisms has not been studied. The aim of the present study was to evaluate the in vitro antimicrobial properties of nanosilver on two dental plaque microorganisms and to compare it with chlorhexidine .
Materials and Methods : In this experimental study, antibacterial effects of silver nanoparticles and chlorhexidine against Streptococus sanguis and Actinomyces viscosus were determined by minimum inhibitory concentration ( MIC ) and minimum bactericidal concentration (MBC) using microdilution method. Each experiment was repeated at least five times to ensure the accuracy of testing.
Results : Results showed that the MIC of soluble silver nanoparticles and chlorhexidine for Streptococcus sanguis were 16 and 256 µg/ml , respectively. Soluble silver nanoparticles had an MIC of 4 and chlorhexidine had an MIC of 64 µ g/ml for Actinomyces viscosus . The MBC of soluble silver nanoparticles and chlorhexidine for Streptococcus sanguis were 64 and 512 µg/ml , respectively and for Actinomyces viscosus these figures were 16 and 102 µg/ml , respectively.
Conclusion : Silver nanoparticles have strong antibacterial activity against Streptococus sanguis and Actinomyces viscosus which was achieved by lower doses in comparison to chlorhexidine mouthwash.
 Key words : Silver Nanoparticles - Chlorhexidine - Resistante - Streptococcus Sanguis - Actinomyces viscosus
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 Corresponding Author : Dr. Sharif F ., Dentist.
e.mail: fateme.sharif@yahoo.com Â