525 Influence of enamel surface pretreatments on its microhardness throughout bleaching

Thursday, March 22, 2012: 3:30 p.m. - 4:45 p.m.
Presentation Type: Poster Session
A.D.N. LAGO1, P. FREITAS2, V.A. SILVA3, W. STEAGALL1, and N. GARONE-NETTO1, 1Restorative Dentistry, University of São Paulo, São Paulo, Brazil, 2Restorative Dentistry, University of São Paulo, Santana de Parnaíba, Brazil, 3Restorative Dentistry, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
Objectives: The aim of this in vitro study was to assess the changes on enamel microhardness when exposing it to fluoride, CPP-ACP or Nd: YAG laser associated with fluoride 24 h before the whitening treatment. Methods: Forty bovine enamel blocks had their surfaces planned and polished and were randomly divided into four experimental groups (n=10): G1 – control (no surface treatment), G2 – fluoride, G3 - CPP-ACP and G4 - Nd: YAG laser + fluoride. After 24 h, the samples were bleached with 35% hydrogen peroxide. Knoop Microhardness tests were performed on specimens' surface before (baseline) and after surface treatment, and after bleaching procedures (immediately and 7 days). The average microhardness (5 indentations) at each time interval was considered for statistical analysis. ANOVA and Tukey tests were performed (α=5%). Results: Results have shown statistical significant differences between the experimental groups immediately after the whitening treatment (G1 – 206.20±13.14, G2 – 248.80±30.33, G3 – 245.90±25.66, G4 – 241.80±22.68). Enamel microhardness values were recovered for all experimental groups after 7-days storage in artificial saliva, expect for the control group. Conclusion: It was concluded that enamel surface treatments 24 hours before whitening procedures were able to prevent significant mineral loss immediately after.
This abstract is based on research that was funded entirely or partially by an outside source: CAPES

Keywords: Bleach, Enamel, Lasers and Mineralization
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