title: Properties of composite materials used for bracket bonding.
abstract: The purpose of this study was to evaluate in vitro the shear bond strength to enamel, flexural strength, flexural modulus, and contraction stress of one orthodontic composite and two flowable composites. Orthodontic brackets were bonded to 45 human maxillary premolars with the composites Transbond XT, Filtek Z-350 flow and Opallis flow and tested for shear bond strength. For measurement of flexural strength and flexural modulus, specimens were fabricated and tested under flexion. For the contraction stress test, cylindrical specimens were tested and an extensometer determined the height of the specimens. The data were subjected to one-way ANOVA and Tukey's test (α=0.05). The shear bond strength values were significantly lower (p<0.05) for the flowable composites compared with the orthodontic composite. For the flexural strength, no statistically significant difference was found among the composites (p>0.05) while the flexural modulus was significantly higher (p<0.05) for Transbond XT than for Filtek Z-350 flow and Opallis flow. The orthodontic composite presented significantly lower contraction stress values than the flowable composites (p<0.05). The light-activated orthodontic composite material presented higher flexural modulus and shear bond strength and lower contraction stress than both flowable composites.
authors: Department of Dentistry 1, Dental School, Federal University of Maranhão, São Luis, MA, Brazil.
authors: Ana Caroline Silva
authors: AC
authors: Gama
authors: André Guaraci de Vito
authors: AG
authors: Moraes
authors: Lilyan Cardoso
authors: LC
authors: Yamasaki
authors: Alessandro Dourado
authors: AD
authors: Loguercio
authors: Ceci Nunes
authors: CN
authors: Carvalho
authors: José
authors: J
authors: Bauer
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000268:Adhesiveness; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry; D003743:Dental Enamel / Q000648:ultrastructure; D003799:Dental Stress Analysis / Q000295:instrumentation; D055119:Elastic Modulus; D006801:Humans; D055115:Light-Curing of Dental Adhesives / Q000295:instrumentation; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D009967:Orthodontic Appliances; D010756:Phosphoric Acids / Q000737:chemistry; D018583:Pliability; D011092:Polyethylene Glycols / Q000737:chemistry; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D033081:Shear Strength; D013314:Stress, Mechanical
chemical_list: C554641:Adper single bond 2; D003188:Composite Resins; D003738:Dental Cements; D008689:Methacrylates; D010756:Phosphoric Acids; D011109:Polymethacrylic Acids; D019279:Resin Cements; C477790:Transbond XT; C533204:filtek Z350; C020946:triethylene glycol dimethacrylate; C041979:2,2-bis-(4-(2-methacryloxyethoxy)phenyl)propane; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C030242:phosphoric acid