title: Influence of microhybrid resin and etching times on bleached enamel for the bonding of ceramic brackets.
abstract: The aim of this study was to evaluate the shear bond strength (SBS) of polycrystalline ceramic brackets (PCB) bonded after bleaching treatment using different composite resins and enamel etching times. A total of 144 bovine incisors were randomly divided into two study groups (n = 72, each) as follows: G1, enamel bleached with 35% hydrogen peroxide, and G2 (control group), enamel unbleached. After the bleaching treatment, the samples were stored in artificial saliva for 14 days. These groups were further divided into two subgroups (n = 36, each) as follows: GA, brackets bonded with Transbond XT (3M) and GB, brackets bonded with Filtek Z250 (3M). For each resin used, three different etching times with 37% phosphoric acid (15, 30 and 60 seconds) were tested. SBS tests were performed using a universal testing machine (EMIC), and the adhesive remnant index (ARI) score was verified. Significant differences among the three experimental conditions and interactions between the groups were observed. The type of composite resin accounted for 24% of the influence on the bond strength, whereas the etching time and bleaching treatment accounted for 14.5% and 10% of the influence on bond strength, respectively. The ARI revealed that the most common area of adhesion failure was at the composite resin-bracket interface. The type of composite resin, etching time and external bleaching significantly influenced the SBS of PCB on enamel, even after 14 days of saliva storage.
authors.affiliation: Department of Dentistry, School of Dentistry, Univ CEUMA, São Luis, MA, Brazil. leilyfiroozmand@hotmail.com
authors.forename: Leily Macedo
authors.initials: LM
authors.lastname: Firoozmand
authors.forename: Juliana Viana Pereira
authors.initials: JV
authors.lastname: Brandão
authors.forename: Melissa Proença Nogueira
authors.initials: MP
authors.lastname: Fialho
mesh_terms: D000134:Acid Etching, Dental; D000818:Animals; D002417:Cattle; D002516:Ceramics / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000737:chemistry; D003743:Dental Enamel / Q000187:drug effects*; D006861:Hydrogen Peroxide / Q000737:chemistry; D008422:Materials Testing; D016910:Orthodontic Brackets; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012464:Saliva, Artificial; D033081:Shear Strength; D013499:Surface Properties; D013997:Time Factors; D014073:Tooth Bleaching / Q000379:methods*
chemical_list: D003188:Composite Resins; D003738:Dental Cements; D010756:Phosphoric Acids; D019279:Resin Cements; D012464:Saliva, Artificial; D006861:Hydrogen Peroxide; C030242:phosphoric acid