title: Peroxide bleaching agent effects on enamel surface microhardness, roughness and morphology.
abstract: The aim of this study was to evaluate the surface roughness, microhardness and morphology of human enamel exposed to six bleaching agents (at baseline and post-treatment). Human dental enamel samples were obtained from human third molars and randomly divided into seven groups (n = 11): control, Whiteness Perfect--10% carbamide peroxide (10% CP), Colgate Platinum--10% CP, Day White 2Z--7.5% hydrogen peroxide (7.5% HP), Whiteness Super--3% CP, Opalescence Quick--35% CP and Whiteness HP--35% HP. Bleaching agents were applied according to manufacturers' instructions. The control group remained not treated and stored in artificial saliva. Microhardness testing was performed with a Knoop indentor and surface roughness was analyzed with a profilometer. Morphologic observations were carried out with scanning electron microscopy (SEM). Results were statistically analyzed by two-way analysis of variance and Tukey's test (5%), and revealed a significant decrease in microhardness values and a significant increase in surface roughness post-bleaching. Changes in enamel morphology after bleaching were observed under SEM. It was concluded that bleaching agents can alter the microhardness, roughness and morphology of dental enamel surface.
authors.affiliation: Department of Restorative Dentistry, School of Dentistry of Piracicaba, State University of Campinas.
authors.forename: Cristiane Franco
authors.initials: CF
authors.lastname: Pinto
authors.forename: Rogério de
authors.initials: Rd
authors.lastname: Oliveira
authors.forename: Vanessa
authors.initials: V
authors.lastname: Cavalli
authors.forename: Marcelo
authors.initials: M
authors.lastname: Giannini
mesh_terms: D000077463:Carbamide Peroxide; D003743:Dental Enamel / Q000187:drug effects* / Q000648:ultrastructure; D004338:Drug Combinations; D006244:Hardness / Q000187:drug effects; D006801:Humans; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000187:drug effects / Q000648:ultrastructure; D016877:Oxidants / Q000009:adverse effects / Q000494:pharmacology*; D010545:Peroxides / Q000009:adverse effects / Q000494:pharmacology*; D014073:Tooth Bleaching; D014508:Urea / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea