title: Caries arresting effect of silver diamine fluoride on dentine carious lesion with S. mutans and L. acidophilus dual-species cariogenic biofilm.
abstract: OBJECTIVE
  This in vitro study investigated the effects of silver diamine fluoride (SDF) on dentine carious lesion with cariogenic biofilm.
  
  
  METHODS
  Thirty human dentine blocks were inoculated with Streptococcus mutans and Lactobacillus acidophilus dual-species biofilm to create carious lesion. They were equally divided into test and control group to receive topical application of SDF and water. After incubation anaerobically using micro-well plate at 37oC for 7 days, the biofilms were evaluated for kinetics, morphology and viability by colony forming units (CFU), scanning electron microscopy (SEM), and confocal microscopy (CLSM), respectively. The carious lesion underwent crystal characteristics analysis, evaluation of the changes in chemical structure and density of collagen fibrils using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and immune-labeling.
  
  
  RESULTS
  The log CFU of S. mutans and L. acidophilus in the test group was significantly lower than control group. SEM and CLSM showed confluent biofilm in control group, but not in test group. XRD showed the loss of crystallinity of dentine due to the dissolution of hydroxyapatite crystal structure in test group was less than control group. FTIR showed that log [Amide I: HPO42-] for test vs. control group was 0.31±0.10 vs. 0.57±0.13 (p<0.05). The gold-labeling density in test vs. control group was 8.54±2.44/µm2 vs. 12.91±4.24/µm2 (p=0.04).
  
  
  CONCLUSIONS
  SDF had antimicrobial activity against the cariogenic biofilms and reduced demineralization of dentine.
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, 34 Hospital Road, Hong Kong SAR, China, chchu@hku.hk.
authors.forename: May-Lei
authors.initials: ML
authors.lastname: Mei
authors.forename: Chun-Hung
authors.initials: CH
authors.lastname: Chu
authors.forename: Kan-Hung
authors.initials: KH
authors.lastname: Low
authors.forename: Ching-Ming
authors.initials: CM
authors.lastname: Che
authors.forename: Edward-Chin-Man
authors.initials: EC
authors.lastname: Lo
mesh_terms: D018441:Biofilms / Q000187:drug effects*; D003731:Dental Caries / Q000188:drug therapy*; D005460:Fluorides, Topical; D006801:Humans; D007779:Lactobacillus acidophilus / Q000187:drug effects* / Q000502:physiology*; D000644:Quaternary Ammonium Compounds / Q000627:therapeutic use*; D018030:Silver Compounds; D013295:Streptococcus mutans / Q000187:drug effects* / Q000502:physiology*
chemical_list: D005460:Fluorides, Topical; D000644:Quaternary Ammonium Compounds; D018030:Silver Compounds; C024633:silver diamine fluoride