title: Analysis by confocal laser scanning microscopy of the MDPB bactericidal effect on S. mutans biofilm CLSM analysis of MDPB bactericidal effect on biofilm.
abstract: Since bacteria remain in the dentin following caries removal, restorative materials with antibacterial properties are desirable to help maintaining the residual microorganisms inactive. The adhesive system Clearfil Protect Bond (PB) contains the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) in its primer, which has shown antimicrobial activity. However, its bactericidal effect against biofilm on the dentin has been little investigated.
  
  
  OBJECTIVE
  The aim of this study was to analyze by confocal laser scanning microscopy (CLSM) and viable bacteria counting (CFU) the MDPB bactericidal effect against S. mutans biofilm on the dentin surface.
  
  
  METHODS
  Bovine dentin surfaces were obtained and subjected to S. mutans biofilm formation in BHI broth supplemented with 1% (w/v) sucrose for 18 h. Samples were divided into three groups, according to the primer application (n=3): Clearfil Protect Bond (PB), Clearfil SE Bond, which does not contain MDPB, (SE) and saline (control group). After the biofilm formation, Live/ Dead stain was applied directly to the surface of each sample. Next, 10 µL of each primer were applied on the samples during 590 s for the real-time CLSM analysis. The experiment was conducted in triplicate. The primers and saline were also applied on the other dentin samples during 20, 90, 300 and 590 s (n=9 for each group and period evaluated) and the CFU were assessed by colonies counting.
  
  
  RESULTS
  The results of the CLSM showed that with the Se application, although non-viable bacteria were detected at 20 s, there was no increase in their count during 590 s. In contrast, after the PB application there was a gradual increase of non-viable bacteria over 590 s.
  
  
  CONCLUSIONS
  The quantitative analysis demonstrated a significant decrease of S. mutans CFU at 90 s PB exposure and only after 300 s of Se application. Protect Bond showed an earlier antibacterial effect than Se Bond.
authors.affiliation: Health and Technology Rural Center, Federal University of Campina Grande, Patos, PB, Brazil. fabigalbi@yahoo.com.br
authors.forename: Fabíola Galbiatti de
authors.initials: FG
authors.lastname: Carvalho
authors.forename: Regina Maria
authors.initials: RM
authors.lastname: Puppin-Rontani
authors.forename: Suzana Beatriz Portugal de
authors.initials: SB
authors.lastname: Fúcio
authors.forename: Thais de Cássia
authors.initials: Tde C
authors.lastname: Negrini
authors.forename: Hugo Lemes
authors.initials: HL
authors.lastname: Carlo
authors.forename: Franklin
authors.initials: F
authors.lastname: Garcia-Godoy
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D058491:Bacterial Load / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects*; D002417:Cattle; D003804:Dentin / Q000382:microbiology; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D018613:Microscopy, Confocal; D011726:Pyridinium Compounds / Q000494:pharmacology*; D019279:Resin Cements / Q000737:chemistry; D013295:Streptococcus mutans / Q000187:drug effects* / Q000502:physiology; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; C503075:Clearfil Protect Bond; C438313:Clearfil SE Bond; D017220:Dentin-Bonding Agents; D011726:Pyridinium Compounds; D019279:Resin Cements; C089392:methacryloyloxydodecylpyridinium bromide