title: Morphological evaluation of enamel surface after application of two 'home' whitening products.
abstract: OBJECTIVE
  The purpose of this study was to investigate the effect on enamel surface morphology of two commercially available bleaching products (AZ Whitestrips 6% hydrogen peroxide - Procter & Gamble; Platinum TWS 10% carbamide - Colgate Oral Pharmaceuticals) and their ability to prevent enamel demineralization in the presence of cariogenic solution, with or without saliva.
  
  
  METHODS
  Forty sound teeth were used to obtain 90 enamel fragments. Lactic acid (pH = 4.4) was used as a demineralizing cariogenic solution. The specimens were randomized into eight groups: Group A: product A + cariogenic solution; Group B: product B + cariogenic solution; Group C: cariogenic solution; Group D: (control group) stored in deionized water; Group E: product A + deionized water; Group F: product B + deionized water; Group G: product A + saliva; Group H: product B + saliva. Scanning electron microscope (SEM) analysis was performed to detect the type of lesions induced by the treatments. A score rating system was used to perform a non-parametric statistical analysis.
  
  
  RESULTS
  Our study confirms that enamel alterations (i.e. removal of intraprismatic core and presence of deep porosities and pits) occur as a result of the application of a cariogenic solution (lactic acid). The enamel surface presented a honeycomb surface only in untreated samples previously stored in lactic acid solution. Conversely, both products were able to prevent enamel alterations caused by exposure to lactic acid. Saliva treatment reduced the degree of enamel lesions of both treated and untreated groups. Treatment with product A achieved better preservation of enamel integrity.
  
  
  CONCLUSIONS
  Whitening treatment conducted with two 'home' bleaching agents had no adverse effects on enamel surface morphology. Several morphological aspects suggest that the tested products may even prevent demineralization of the enamel surface after exposure to lactic acid.
authors.affiliation: Department of Dental Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy. cesare.nucci@fastwebnet.it
authors.forename: Cesare
authors.initials: C
authors.lastname: Nucci
authors.forename: Silvia
authors.initials: S
authors.lastname: Marchionni
authors.forename: Gabriela
authors.initials: G
authors.lastname: Piana
authors.forename: Annalisa
authors.initials: A
authors.lastname: Mazzoni
authors.forename: Carlo
authors.initials: C
authors.lastname: Prati
mesh_terms: D000077463:Carbamide Peroxide; D002326:Cariogenic Agents / Q000494:pharmacology; D003743:Dental Enamel / Q000187:drug effects*; D004338:Drug Combinations; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D019344:Lactic Acid / Q000494:pharmacology; D008855:Microscopy, Electron, Scanning; D008963:Molar; D016877:Oxidants / Q000494:pharmacology*; D010545:Peroxides / Q000494:pharmacology*; D016062:Porosity; D018709:Statistics, Nonparametric; D013499:Surface Properties / Q000187:drug effects; D014073:Tooth Bleaching; D017001:Tooth Demineralization / Q000139:chemically induced / Q000517:prevention & control*; D014508:Urea / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D002326:Cariogenic Agents; D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D000077463:Carbamide Peroxide; D019344:Lactic Acid; D014508:Urea; D006861:Hydrogen Peroxide