title: Influence of remineralizing gels on bleached enamel microhardness in different time intervals.
abstract: This study evaluated the influence of bleaching gel pH, the effect of applying remineralizing gels after bleaching and the effect of artificial saliva on enamel microhardness. Seventy bovine incisors were divided into three groups: Group 1 (n=10) received no bleaching procedure (control); Group 2 was bleached with a 35% hydrogen peroxide neutral gel (n=30) and Group 3 was bleached with a 35% hydrogen peroxide acid gel (n=30). Each experimental group was subdivided into three groups (n=10) according to the post-bleaching treatment: storage in artificial saliva, application of a fluoride gel and application of a combination of calcium and fluoride gel. The specimens were stored in artificial saliva for 7, 15 and 30 days and enamel microhardness was evaluated. The Vickers microhardness data were analyzed by three-way RM ANOVA, which revealed a significant difference only for treatment factor. The Tukey's test showed that the groups bleached followed by no additional treatment exhibited microhardness means significantly lower than the bleached groups treated with remineralizing gels. The Dunnet's test showed a significant difference only for the group bleached with acid gel without remineralizing treatment compared to the control group measured immediately after bleaching. It was concluded that acid bleaching gel significantly reduced enamel microhardness and that use of remineralizing gels after bleaching can significantly enhance the microhardness of bleached enamel.
authors.affiliation: Department of Restorative Dentistry at São José dos Campos School of Dentistry-UNESP--São Paulo State University, São José dos Campos, SP, Brazil.
authors.forename: Alessandra Bühler
authors.initials: AB
authors.lastname: Borges
authors.forename: Karen Cristina Kazue
authors.initials: KC
authors.lastname: Yui
authors.forename: Thaís Corrêa
authors.initials: TC
authors.lastname: D'Avila
authors.forename: Camila Lurie
authors.initials: CL
authors.lastname: Takahashi
authors.forename: Carlos Rocha Gomes
authors.initials: CR
authors.lastname: Torres
authors.forename: Alexandre Luis Souto
authors.initials: AL
authors.lastname: Borges
mesh_terms: D000818:Animals; D002130:Calcium Phosphates / Q000494:pharmacology; D002417:Cattle; D003743:Dental Enamel / Q000187:drug effects*; D005782:Gels / Q000494:pharmacology; D006244:Hardness / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000009:adverse effects; D016877:Oxidants / Q000009:adverse effects; D012969:Sodium Fluoride / Q000494:pharmacology; D013997:Time Factors; D014073:Tooth Bleaching / Q000009:adverse effects*; D014089:Tooth Remineralization / Q000379:methods*
chemical_list: D002130:Calcium Phosphates; D005782:Gels; D016877:Oxidants; D012969:Sodium Fluoride; C020243:calcium phosphate; D006861:Hydrogen Peroxide