title: Effect of silver and fluoride ions on enamel demineralization: a quantitative study using micro-computed tomography.
abstract: BACKGROUND
  This study aimed to investigate the effect of silver and fluoride ions on demineralization of enamel.
  
  
  METHODS
  The coronal parts of 40 extracted sound premolars were prepared into tooth blocks. An unvarnished occlusal surface window (OW) and a flat buccal/lingual surface window (FW) were created for each tooth by covering all other surfaces with an acid-resistant varnish. These blocks were randomly allocated into four groups of 10 blocks each and immersed in respective solutions for 5 minutes: Group 1--2.36 M silver fluoride; Group 2--2.36 M potassium fluoride; Group 3--2.36 M silver nitrate; and Group 4--deionized water. After 7-day immersion in a buffered demineralization solution at pH 4.4, micro-CT scans were taken.
  
  
  RESULTS
  Mean lesion depth in the FW area for tooth blocks in AgF, KF, AgNO(3) and control groups were 0 μm, 3.3 ± 10.3 μm, 156.3 ± 30.8 μm, and 173.6 ± 48.6 μm, respectively (p < 0.001). The difference in mean lesion depth between the AgNO(3) and control groups was not statistically significant (p > 0.05). Similar OW and FW lesions were observed in tooth blocks in the AgNO(3) and control groups.
  
  
  CONCLUSIONS
  Topical application of a 2.36 M fluoride solution can inhibit demineralization of enamel while topical application of silver ions has little effect.
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Pokfulam, Hong Kong, China.
authors.forename: B Y
authors.initials: BY
authors.lastname: Liu
authors.forename: E C M
authors.initials: EC
authors.lastname: Lo
authors.forename: C M T
authors.initials: CM
authors.lastname: Li
mesh_terms: D001641:Bicuspid; D003743:Dental Enamel / Q000000981:diagnostic imaging / Q000473:pathology*; D005459:Fluorides / Q000494:pharmacology / Q000627:therapeutic use*; D005460:Fluorides, Topical; D006244:Hardness / Q000187:drug effects; D006801:Humans; D007477:Ions; D017680:Potassium Compounds / Q000494:pharmacology / Q000627:therapeutic use*; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology / Q000627:therapeutic use; D018030:Silver Compounds / Q000494:pharmacology / Q000627:therapeutic use*; D012835:Silver Nitrate / Q000494:pharmacology / Q000627:therapeutic use; D017001:Tooth Demineralization / Q000000981:diagnostic imaging / Q000517:prevention & control*; D055114:X-Ray Microtomography
chemical_list: D005460:Fluorides, Topical; D007477:Ions; D017680:Potassium Compounds; D000644:Quaternary Ammonium Compounds; D018030:Silver Compounds; C105022:silver fluoride; C033320:potassium fluoride; D012835:Silver Nitrate; C024633:silver diamine fluoride; D005459:Fluorides