title: The antibacterial properties of composite resin containing nanosilver against Streptococcus mutans and Lactobacillus.
abstract: OBJECTIVE
  The aim was to evaluate the antibacterial properties of composite resin containing nanosilver against Streptococcus mutans (SM) and Lactobacillus (L).
  
  
  METHODS
  Nanosilver was added to Z250 composite at 0.5 and 1% by weight. In order to confirm the homogenous distribution of the nanoparticles in the composite resin, SEM-EDX analysis was performed on one sample in each group. Z250 composite without nanosilver was used as control. Direct contact test was used to test the antibacterial properties of nanoparticle-loaded composites: 0.001 ml of 0.5 Mc Farland suspension of MS and L was placed on composite disks, and incubated for 1 hour in 5 to 10% CO2 incubator at 37°C. Samples were placed in 0.5 ml of sterile BHI broth and incubated for 2 hours in CO2 incubator. Afterwards, 0.001 ml liquid from each medium was distributed on blood agar plates and incubated for 48 hours in CO2 incubator. The numbers of bacterial colonies were counted visually. Data were analyzed using Two-way ANOVA and Tukey HSD test. Significance level was set at 0.05.
  
  
  RESULTS
  Addition of nanosilver to composite resin had a significant effect on reduction of the number of SM and L colonies (p = 0.000). The antibacterial properties of composite resins are different depending on the concentration of nanosilver (p = 0.014). Tukey test indicated that increase in the concentration of nanosilver caused the increase in antibacterial properties of composite resin.
  
  
  CONCLUSIONS
  Addition of silver nanoparticles to Z250 composite could significantly inhibit the growth of Streptococcus mutans and Lactobacillus on the surface of this composite.
  
  
  CONCLUSIONS
  The addition of nanosilver to Z250 composite could inhibit the growth of SM and L on the surface of the restoration and therefore prevent the occurrence of secondary caries.
authors.affiliation: Assistant Professor, Department of Operative Dentistry, Dental School International Branch of Shahid Beheshti University of Medical Sciences, Iran.
authors.forename: Mohadese
authors.initials: M
authors.lastname: Azarsina
authors.affiliation: Associate Professor, Department of Operative Dentistry, Dental Research Center, Hamadan University of Medical Sciences, Iran.
authors.forename: Shahin
authors.initials: S
authors.lastname: Kasraei
authors.affiliation: Full Professor, Department of Microbiology, Medical School, Hamadan University of Medical Sciences, Iran.
authors.forename: Rasoul
authors.initials: R
authors.lastname: Yousef-Mashouf
authors.affiliation: Postgraduate Student, Department of Oral and Maxillofacial Surgery Dental School, Shahid Beheshti University of Medical Sciences, Iran.
authors.forename: Nima
authors.initials: N
authors.lastname: Dehghani
authors.affiliation: Assistant Professor, Department of Operative Dentistry, Dental School Hamadan University of Medical Sciences, Iran, e-mail: mshirinzad@ ymail.com.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Shirinzad
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D058491:Bacterial Load / Q000187:drug effects; D001431:Bacteriological Techniques; D003188:Composite Resins / Q000737:chemistry / Q000494:pharmacology*; D003764:Dental Materials / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D007778:Lactobacillus / Q000187:drug effects*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D013295:Streptococcus mutans / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D003188:Composite Resins; D003764:Dental Materials; C444701:Filtek Z250