title: The inhibitory effects of silver diamine fluorides on cysteine cathepsins.
abstract: OBJECTIVE
  The expression of cysteine cathepsins in human carious dentine suggests that this enzyme contributes to the collagen degradation in caries progress. This study investigated whether silver diamine fluoride (SDF) inhibited the activity of cysteine cathepsins.
  
  
  METHODS
  Three commercial SDF solutions with concentrations at 38%, 30% and 12% were studied. Two fluoride solutions with the same fluoride ion (F(-)) concentrations as the 38% and 12% SDF solutions, and 2 silver solutions with the same silver ion (Ag(+)) concentrations as the 38% and 12% SDF solutions were prepared. Five samples of each experimental solution were used to study their inhibitory effect on two cathepsins (B and K) using cathepsin assay kits. Positive control contained assay buffer and cathepsins dilution was used to calculate the percentage inhibition (difference between the mean readings of the test solution and control solution divided by that of the control group).
  
  
  RESULTS
  The percentage inhibition of 38%, 30% and 12% SDF on cathepsin B were 92.0%, 91.5% and 90.3%, respectively (p<0.001); on cathepsin K were 80.6%, 78.5% and 77.9%, respectively (p<0.001). Ag(+) exhibited the inhibitory effect against both cathepsin B and K with or without the presence of F(-) (p<0.01). The solutions containing Ag(+) have significantly higher inhibitory effect than the solutions containing F(-) only (p<0.01).
  
  
  CONCLUSIONS
  According to this study, SDF solution at all 3 tested concentrations significantly inhibited the activity of cathepsin B and K.
authors: Faculty of Dentistry, The University of Hong Kong, Hong Kong Special Administrative Region.
authors: May L
authors: ML
authors: Mei
authors: Faculty of Dentistry, The University of Hong Kong, Hong Kong Special Administrative Region.
authors: L
authors: L
authors: Ito
authors: Faculty of Dentistry, The University of Hong Kong, Hong Kong Special Administrative Region; College of Stomatology, Anhui Medical University, Hefei, PR China.
authors: Y
authors: Y
authors: Cao
authors: College of Stomatology, Anhui Medical University, Hefei, PR China.
authors: Q L
authors: QL
authors: Li
authors: Faculty of Dentistry, The University of Hong Kong, Hong Kong Special Administrative Region. Electronic address: chchu@hku.hk.
authors: C H
authors: CH
authors: Chu
authors: Faculty of Dentistry, The University of Hong Kong, Hong Kong Special Administrative Region.
authors: Edward C M
authors: EC
authors: Lo
mesh_terms: D002327:Cariostatic Agents / Q000008:administration & dosage / Q000494:pharmacology; D002401:Cathepsin B / Q000037:antagonists & inhibitors*; D056657:Cathepsin K / Q000037:antagonists & inhibitors*; D004735:Energy Transfer; D005453:Fluorescence; D005460:Fluorides, Topical; D006801:Humans; D007202:Indicators and Reagents; D008422:Materials Testing; D000644:Quaternary Ammonium Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D018030:Silver Compounds; D012835:Silver Nitrate / Q000008:administration & dosage / Q000494:pharmacology; D012969:Sodium Fluoride / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D002327:Cariostatic Agents; D005460:Fluorides, Topical; D007202:Indicators and Reagents; D000644:Quaternary Ammonium Compounds; D018030:Silver Compounds; D012969:Sodium Fluoride; D012835:Silver Nitrate; C024633:silver diamine fluoride; C533912:CTSB protein, human; D002401:Cathepsin B; C534130:CTSK protein, human; D056657:Cathepsin K
keywords: Arrest caries; Cysteine cathepsins; Dentine; Matrix metalloproteinases; Silver diamine fluoride