title: Effect of bleaching agents on the flexural strength of bovine dentin.
abstract: The aim of this study was to evaluate the effect of bleaching on the flexural strength of bovine dentin, using bleaching agents containing calcium (Whiteness HP Blue and Whiteness Class) and not containing calcium (Whiteness HP and Whiteness Perfect). Sixty bovine incisor tooth slices were obtained and divided into fve experimental groups (n = 12), such as G1, untreated control group; G2, Whiteness HP Max [35% hydrogen peroxide (HP)]; G3, Whiteness HP Blue (35% HP); G4, Whiteness Class (7.5% HP) and G5, Whiteness Perfect (22% carbamide peroxide). Samples were submitted to bleaching treatment according to the manufacturers' instructions. The control group remained in artificial saliva during bleaching. After bleaching, the enamel was removed and dentin specimens (7 mm length × 1.7 mm width × 0.5 mm thickness) were prepared. Samples were tested in a universal testing machine (EMIC). Data were analyzed by analysis variance (ANOVA) and Tukey's test. Differences between the groups were identified by ANOVA. The mean values (± standard deviation) for the experimental groups, such as (in MPa) G1 = 19.05 ± 2.68 a; G2 = 12.69 ± 4.52 b; G3 = 16.39 ± 3.74 ab; G4 = 14.90 ± 5.60 ab; and G5 = 12.71 ± 2.25 b. Groups with the same lowercase letter were significantly different from each other. The presence of calcium in bleaching agents appeared to influence the flexural strength of bovine dentin after bleaching treatment, for both office bleaching (35% HP) and home bleaching (7.5% HP).
authors.affiliation: Associate Professor, Department of Restorative Dentistry, University of North Parana (UNOPAR), Londrina, Parana, Brazil, e-mail: berger.sandrine@gmail.com.
authors.forename: Sandrine Bittencourt
authors.initials: SB
authors.lastname: Berger
authors.affiliation: Graduate Student, Department of Restorative Dentistry, University of North Parana (UNOPAR), Londrina, Parana, Brazil.
authors.forename: Rafaela
authors.initials: R
authors.lastname: Pazenhagen
authors.affiliation: Graduate Student, Department of Restorative Dentistry, University of North Parana (UNOPAR), Londrina, Parana, Brazil.
authors.forename: Natan
authors.initials: N
authors.lastname: Martinelli
authors.affiliation: Associate Professor, Department of Restorative Dentistry, University of North Parana (UNOPAR), Londrina, Parana, Brazil.
authors.forename: Sandra Kiss
authors.initials: SK
authors.lastname: Moura
authors.affiliation: Associate Professor, Department of Restorative Dentistry, School of Dentistry Meridional Faculty (IMED), Passo Fundo, Rio Grande do Sul, Brazil.
authors.forename: Rodrigo Varella de
authors.initials: RV
authors.lastname: Carvalho
authors.affiliation: Associate Professor, Department of Restorative Dentistry, University of North Parana (UNOPAR), Londrina, Parana, Brazil.
authors.forename: Ricardo Danil
authors.initials: RD
authors.lastname: Guiraldo
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002118:Calcium / Q000494:pharmacology; D000077463:Carbamide Peroxide; D002417:Cattle; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000187:drug effects*; D006861:Hydrogen Peroxide / Q000008:administration & dosage / Q000494:pharmacology; D010545:Peroxides / Q000494:pharmacology; D018583:Pliability; D012464:Saliva, Artificial / Q000737:chemistry; D013314:Stress, Mechanical; D013997:Time Factors; D014073:Tooth Bleaching / Q000379:methods; D058205:Tooth Bleaching Agents / Q000494:pharmacology*; D014508:Urea / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D010545:Peroxides; D012464:Saliva, Artificial; D058205:Tooth Bleaching Agents; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide; D002118:Calcium