title: Effect of a glass ionomer cement and a fluoride varnish on cross-sectional microhardness values of artificial occlusal caries: in vitro study.
abstract: BACKGROUND
  Active white spot lesions (WSLs) are a great concern to clinicians.
  
  
  OBJECTIVE
  This in vitro experiment analyzed cross-sectional microhardness (CSMH) values of occlusal artificially induced active WSLs (control groups D/A, D/B and D/C) along with experimental groups where these lesions were: Exposed to an artificial high risk cariogenic challenge (HRCC) using pH cycling; treated with a glass ionomer cement (GIC) and then exposed to artificial HRCC; or a fluoride varnish (FV) and afterwards submitted to the same artificial HRCC.
  
  
  METHODS
  Sixty unerupted human third molars were sectioned buccolingually on the occlusal surface and demineralized for 42 days. One half of each tooth was allocated to control groups (D/A, D/B, and D/C) and the other were used as test groups: A (pH cycling); B (GIC + pH cycling); and C (FV + pH cycling). CSMH test was performed for sound, demineralized, and treated specimens.
  
  
  METHODS
  Different depths for CSMH values did not have a normal distribution (Kolmogrov-Smirnov test) and for that matter Wilcoxon and T Test were applied (significance level of 5%).
  
  
  RESULTS
  Mean depth of the lesion was 120 μm. A number of samples both in the test groups (n = 37) as in control groups (n = 47) had a lower Knoo p value (softening) or surface erosion. Comparisons between control and test groups only showed statistical difference at a depth 140 μm (P = 0.010) in control group D/A and for test group B at 20 μm (P = 0.004) and at 40 μm (P = 0.007).
  
  
  CONCLUSIONS
  This in vitro study demonstrated that the use of GIC over an artificial active WSLs and exposed to an artificially HRCC setting tend to express some effect in increased surface KHN values.
authors: Department of Community and Preventive Dentistry, State University of Rio de Janeiro, Brazil.
authors: M W M
authors: MW
authors: Souchois
authors: R S
authors: RS
authors: Vieira
mesh_terms: D019412:Anatomy, Cross-Sectional; D002326:Cariogenic Agents / Q000494:pharmacology; D002327:Cariostatic Agents / Q000494:pharmacology*; D003731:Dental Caries / Q000473:pathology*; D003743:Dental Enamel / Q000187:drug effects / Q000473:pathology; D005460:Fluorides, Topical / Q000494:pharmacology*; D005899:Glass Ionomer Cements / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D019228:Tooth Crown / Q000187:drug effects / Q000473:pathology; D017001:Tooth Demineralization / Q000473:pathology; D014077:Tooth Erosion / Q000473:pathology
chemical_list: D002326:Cariogenic Agents; D002327:Cariostatic Agents; D005460:Fluorides, Topical; D005899:Glass Ionomer Cements