title: Effect of 10% carbamide peroxide bleaching on sound and artificial enamel carious lesions.
abstract: This study evaluated the effect of 10% carbamide peroxide (CP) bleaching on Knoop surface microhardness (KHN) and morphology of sound enamel and enamel with early artificial caries lesions (CL) after pH-cycling model (pHcm). Human dental enamel blocks were randomly divided into 6 groups (n=10): 1 - sound enamel bleached (S) with CP (Rembrandt/Den-Mat); 2 - S and submitted to pHcm; 3 - CL bleached with CP; 4 - CL stored in artificial saliva and submitted to pHcm; 5 - CL treated with placebo gel and submitted to pHcm; 6 - CL bleached with CP and submitted to pHcm. Enamel blocks with known initial KHN values were demineralized (groups 3 to 6) and submitted to 12 day pHcm (groups 2, 4, 5 and 6). After demineralization and treatments, KHN was determined and the specimens were examined using scanning electron microscopy (SEM). Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. The results showed that among CL groups (3 to 6) only the group 3 presented remineralization after treatments. S groups (1 and 2) showed higher KHN and presented less formation of porosities on enamel surface than CL groups after treatments. In conclusion, bleaching procedures on enamel with CL did not exacerbate the demineralization, but should be indicated with caution.
authors.affiliation: Departament of Restorative Dentistry, Dental School of Piracicaba, State University of Campinas, Piracicaba 13414-903, SP, Brazil.
authors.forename: Cristiane Franco
authors.initials: CF
authors.lastname: Pinto
authors.forename: Adriana Franco
authors.initials: AF
authors.lastname: Paes Leme
authors.forename: Vanessa
authors.initials: V
authors.lastname: Cavalli
authors.forename: Marcelo
authors.initials: M
authors.lastname: Giannini
mesh_terms: D000077463:Carbamide Peroxide; D003731:Dental Caries / Q000473:pathology*; D003743:Dental Enamel / Q000187:drug effects* / Q000473:pathology / Q000648:ultrastructure; D004338:Drug Combinations; D006244:Hardness / Q000187:drug effects; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D016877:Oxidants / Q000009:adverse effects*; D010545:Peroxides / Q000009:adverse effects*; D016062:Porosity; D012464:Saliva, Artificial; D014073:Tooth Bleaching / Q000009:adverse effects*; D017001:Tooth Demineralization / Q000139:chemically induced*; D014089:Tooth Remineralization; D014508:Urea / Q000009:adverse effects / Q000031:analogs & derivatives*
chemical_list: D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D012464:Saliva, Artificial; D000077463:Carbamide Peroxide; D014508:Urea