title: Effect of different bleaching systems on the ultrastructure of bovine dentin.
abstract: The aim of this study was to evaluate in vitro the effect of different in-office bleaching systems on the surface morphology of bovine dentin. Thirty tooth fragments measuring 4 x 4mm, containing enamel and dentin, were obtained from the crowns of extracted bovine incisors. Samples were subjected to simulated intracoronal bleaching techniques using conventional (Opalescence Endo and Whiteness Super Endo) and light-activated systems (Opalescence Xtra) and Whiteness HP Maxx). Controls were treated with either sodium perborate mixed with 10% hydrogen peroxide or no bleaching agent. The samples were observed under SEM and the recorded images were evaluated for topographic alterations. The ultrastructural alterations of dentin observed in this study varied greatly between groups according to the products used. Higher pH products (Whiteness HP Maxx) and Opalescence Xtra) associated with in-office techniques yielded better maintenance of dentin ultrastructure. Apparently, both low pH and hydrogen peroxide oxidation play a role in altering the ultrastructure of dentin during internal dental bleaching. The use of alkaline products with reduced time of application (in-office techniques) may decrease such morphological alterations.
authors.affiliation: Ribeirão Preto Dental School, University of São Paulo, Ribeirão Preto, São Paulo.
authors.forename: Laise Daniela
authors.initials: LD
authors.lastname: Carrasco-Guerisoli
authors.forename: Renato Jonas dos Santos
authors.initials: RJ
authors.lastname: Schiavoni
authors.forename: Juliana Machado
authors.initials: JM
authors.lastname: Barroso
authors.forename: Danilo Mathias Zanello
authors.initials: DM
authors.lastname: Guerisoli
authors.forename: Jesus Djalma
authors.initials: JD
authors.lastname: Pécora
authors.forename: Izabel Cristina
authors.initials: IC
authors.lastname: Fröner
mesh_terms: D000818:Animals; D000077463:Carbamide Peroxide; D002417:Cattle; D003786:Dental Pulp Cavity / Q000187:drug effects; D003804:Dentin / Q000187:drug effects / Q000648:ultrastructure*; D004338:Drug Combinations; D007180:Incisor; D010545:Peroxides / Q000009:adverse effects*; D012390:Root Canal Therapy / Q000379:methods; D013499:Surface Properties; D014073:Tooth Bleaching / Q000379:methods*; D019553:Tooth, Nonvital; D014508:Urea / Q000009:adverse effects / Q000031:analogs & derivatives*
chemical_list: D004338:Drug Combinations; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea