title: Antimicrobial efficacy of 3.8% silver diamine fluoride and its effect on root dentin.
abstract: BACKGROUND
  This study investigated the use of 3.8% silver diamine fluoride (Ag[NH3]2F) as an antibacterial agent against Enterococcus faecalis biofilms and its ability to penetrate dentinal tubules by the formation of silver salts.
  
  
  METHODS
  Biofilms were generated on membrane filter discs and subjected to 15-minute and 60-minute exposure times with 3.8% Ag(NH3)2F, saturated Ca(OH)2, 5.25% NaOCl (negative control), and 0.9% NaCl (positive control). Cleaned and shaped radicular dentin were applied with Ag(NH3)2F for 24, 48, and 72 hours. The presence of silver salts on the dentin surface was examined using low-pressure scanning electron microscopy.
  
  
  RESULTS
  Both NaOCl and Ag(NH3)2F were effective against E. faecalis biofilms, with no significant difference in reduction of microorganisms for both exposure times. Silver deposits were present on 66.5% of the radicular dentin surfaces after 72-hour application of Ag(NH3)2F as simulated interappointment dressings. Penetration of the silver deposits was observed at most 40 microm into dentinal tubules after smear layer removal.
  
  
  CONCLUSIONS
  Ag(NH3)2F has potential to be used as an antimicrobial root canal irrigant or interappointment dressing, especially in locations in which potential browning/blackening of dentin by metallic silver is not a major concern.
authors.affiliation: Cariology and Operative Dentistry, Department of Restorative Science, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. hiraishinoriko@yahoo.com
authors.forename: Noriko
authors.initials: N
authors.lastname: Hiraishi
authors.forename: Cynthia K Y
authors.initials: CK
authors.lastname: Yiu
authors.forename: Nigel M
authors.initials: NM
authors.lastname: King
authors.forename: Junji
authors.initials: J
authors.lastname: Tagami
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Tay
mesh_terms: D000890:Anti-Infective Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D001431:Bacteriological Techniques; D018441:Biofilms / Q000187:drug effects; D002126:Calcium Hydroxide / Q000494:pharmacology; D015169:Colony Count, Microbial; D019551:Dental Disinfectants / Q000494:pharmacology; D003786:Dental Pulp Cavity / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D003804:Dentin / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D013293:Enterococcus faecalis / Q000187:drug effects; D005460:Fluorides, Topical; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D000644:Quaternary Ammonium Compounds / Q000493:pharmacokinetics / Q000494:pharmacology*; D018915:Root Canal Preparation / Q000379:methods; D018030:Silver Compounds; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000890:Anti-Infective Agents; D019551:Dental Disinfectants; D005460:Fluorides, Topical; D000644:Quaternary Ammonium Compounds; D018030:Silver Compounds; C024633:silver diamine fluoride; D012973:Sodium Hypochlorite; D002126:Calcium Hydroxide