Morphological evaluation of enamel surface after application of two 'home' whitening products.
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.
Nucci
Cesare
C
Department of Dental Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy. cesare.nucci@fastwebnet.it
Marchionni
Silvia
S
Piana
Gabriela
G
Mazzoni
Annalisa
A
Prati
Carlo
C
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
D002326:Cariogenic Agents; D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D000077463:Carbamide Peroxide; D019344:Lactic Acid; D014508:Urea; D006861:Hydrogen Peroxide