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Published on: July 10, 2014
Effect of different home-bleaching techniques for a regular or an extended time on enamel properties
Marianna Sorizini Ferreira De Miranda1, Amal Elzubair Eltom2, Sérgio de Souza Camargo3
1Department of Restorative Dentistry, Faculty of Dentistry, University of Rio de Janeiro State, Rio de Janeiro, RJ, Brazil.
Context:
The side effects of bleaching products are still incompletely known.
Aims:
This work aims to evaluate the effects of bleaching regimens on colour variation, microstructure, roughness, composition and nanohardness of human dental enamel until 8 weeks.
Settings And Design:
: Twenty teeth were cross-sectioned to obtain eighty enamel fragments (50 × 50 mm) divided into four groups: CN (control Negative-artificial saliva), CP10 (10% carbamide peroxide), HP10 (10% hydrogen peroxide), and WS (whitening strips-10% hydrogen peroxide).
Methods And Material:
Roughness (atomic force microscopy-AFM and 3-D surface scanning), morphology (confocal laser scanning microscopy-CLSM and AFM), hardness and elastic modulus (nanoindentation), and composition (Raman microspectroscopy) were analysed before the therapy and after 4 and 8 weeks. Colour measures were performed weekly.
Statistical Analysis Used:
: Two-way ANOVA with repeated measures (P < 0.05).
Results:
Bleaching stabilizes after 3 weeks for HP10 and after 4 weeks for CP10 and WS. Roughness evaluation showed statistical difference for HP10 after 8 weeks for Sa and Sq, for HP10 and WS after 4 weeks and for CP10 after 8 weeks. The same occurred for hardness and elastic modulus. The morphological evaluation demonstrated the most significant effects after 8 weeks of treatment for HP10 and WS. Composition analysis revealed modifications in peaks related to the organic content spectra (protein) with an increase in detection after 4 weeks, followed by a decrease after 8 weeks.
Conclusions:
H2O2-based products caused morphological and compositional alterations on enamel.
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