title: [Effects of three different zinc oxide incorporation on the antibacterial activity against Streptococcus mutans of composite resin].
abstract: OBJECTIVE
  To investigate the effects of incorporating three different zinc oxide (ZnO) on the antibacterial activity of composite resin.
  
  
  METHODS
  The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of nano-ZnO, tetrapod-like zinc oxide whiskers (T-ZnOw), micro-ZnO against Streptococcus mutans were examined by the broth dilution test. Then the three different ZnO were added to the powder of one kind of bicomponent self-cured composite resin at 5% respectively, and the antibacterial activities of the resin specimens were evaluated using the membrane covering method before and after 3-month accelerating aging.
  
  
  RESULTS
  The MIC values of the three different ZnO against Streptococcus mutans were 78.13, 312.50 and 1 250.00 microg/mL respectively and the MBC values were 156.25, 625.00, 1,250.00 microg/mL respectively. The antibacterial ratios of the resin specimens incorporating with 5% of the three different ZnO were (93.58+/-5.95)%, (89.42+/-4.11)% and (78.97+/-3.90)% respectively, while after 3-month accelerating aging those were (89.01+/-7.91)%, (84.63+/-4.72)% and (72.27+/-3.89)%.
  
  
  CONCLUSIONS
  The three different ZnO could improve the antibacterial activity of the composite resin. The nano-ZnO exhibit the strongest antibacterial activity, while the micro-ZnO weakest. The T-ZnOw presents comparatively strong antibacterial activity although with smaller specific surface area.
authors.affiliation: Dept. of Prosthodontics, College of Stomatology, The Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Li-Na
authors.initials: LN
authors.lastname: Niu
authors.forename: Ji-Hua
authors.initials: JH
authors.lastname: Chen
authors.forename: Ming
authors.initials: M
authors.lastname: Fang
authors.forename: Ju-Cai
authors.initials: JC
authors.lastname: Yang
authors.forename: Yul-Hong
authors.initials: YH
authors.lastname: Xiao
authors.forename: Feng
authors.initials: F
authors.lastname: Ni
mesh_terms: D000900:Anti-Bacterial Agents; D003188:Composite Resins; D008826:Microbial Sensitivity Tests; D013295:Streptococcus mutans; D015034:Zinc Oxide
chemical_list: D000900:Anti-Bacterial Agents; D003188:Composite Resins; D015034:Zinc Oxide