title: Can green tea be used to reverse compromised bond strength after bleaching?
abstract: The objective of this study was to evaluate the antioxidant effect of green tea on microtensile bond strength (μTBS) to bleached enamel. Forty-two human third molars were randomly divided into six experimental groups (n = 7 each group): group 1, no treatment; group 2, bleaching (10% carbamide peroxide); group 3, bleaching + 10% sodium ascorbate gel (SA); group 4, bleaching + 10% green tea gel (GT); group 5, SA; and group 6, GT. In groups 2, 3, and 4, bleach was applied onto the enamel surface for 6 h, every day for 14 d. In groups 3 and 5, SA was applied for 1 h; and in groups 4 and 6, GT was applied for 1 h. Immediately after treatment, the specimens were bonded with Adper Single Bond 2 and Filtek Z350 XT. The μTBS of the specimens was tested using a universal testing machine. Fracture mode analysis of the bonded enamel surface was performed using scanning electron microscopy. The mean μTBS values for each group were: group 1, 33.2 ± 5.8 MPa; group 2, 22.6 ± 5.5 MPa; group 3, 30.0 ± 5.2 MPa; group 4, 31.6 ± 3.8 MPa; group 5, 29.1 ± 4.2 MPa; and group 6, 32.2 ± 4.5 MPa. All groups had a higher percentage of mixed failures. In conclusion, green tea can be used as an alternative antioxidant on bleached enamel before bonding procedures.
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, University of North Parana, Londrina, Brazil. berger.sandrine@gmail.com
authors.forename: Sandrine B
authors.initials: SB
authors.lastname: Berger
authors.forename: Renata P
authors.initials: RP
authors.lastname: De Souza Carreira
authors.forename: Ricardo D
authors.initials: RD
authors.lastname: Guiraldo
authors.forename: Murilo B
authors.initials: MB
authors.lastname: Lopes
authors.forename: Sabrina
authors.initials: S
authors.lastname: Pavan
authors.forename: Marcelo
authors.initials: M
authors.lastname: Giannini
authors.forename: Ana K
authors.initials: AK
authors.lastname: Bedran-Russo
mesh_terms: D000704:Analysis of Variance; D000975:Antioxidants / Q000737:chemistry; D001205:Ascorbic Acid / Q000737:chemistry*; D000077463:Carbamide Peroxide; D001840:Dental Bonding / Q000379:methods*; D003743:Dental Enamel / Q000737:chemistry*; D019544:Equipment Failure Analysis; D005782:Gels / Q000737:chemistry; D006801:Humans; D008855:Microscopy, Electron, Scanning; D010545:Peroxides / Q000009:adverse effects*; D019279:Resin Cements / Q000737:chemistry*; D013662:Tea / Q000737:chemistry*; D013718:Tensile Strength; D014073:Tooth Bleaching / Q000009:adverse effects*; D014508:Urea / Q000009:adverse effects / Q000031:analogs & derivatives*
chemical_list: D000975:Antioxidants; D005782:Gels; D010545:Peroxides; D019279:Resin Cements; D013662:Tea; D000077463:Carbamide Peroxide; D014508:Urea; D001205:Ascorbic Acid
keywords: adhesion; dental bleaching; enamel; green tea