title: Shear bond strength of orthodontic brackets bonded with a new self-adhering flowable resin composite.
abstract: OBJECTIVE
  This study aims to assess the shear bond strength (SBS) to enamel and the distribution of failure modes of brackets bonded using a new self-adhering flowable resin composite (Vertise Flow, VF), with or without preliminary phosphoric acid etching (PAE).
  
  
  METHODS
  Eighty extracted premolars were randomly divided into four groups (n = 20): (1) etch-and-rinse adhesive (E&R), PAE/Transbond XT Primer/Transbond XT Paste (3M Unitek); (2) self-etch adhesive (SE), Transbond Plus Self-Etching Primer (3M Unitek)/Transbond XT Paste; (3) VF; (4) PAE/VF. In each group, 10 bracketed teeth were debonded within 30 min, while the remaining teeth were subjected to thermocycling before testing. SBS and adhesive remnant index were recorded.
  
  
  RESULTS
  SE measured significantly lower early SBS than PAE/VF. Early SBSs recorded by VF were slightly higher yet statistically similar to those of E&R. Such levels of adhesion were achieved by VF regardless of preliminary PAE. After thermocycling, VF measured the lowest SBS. When debonded early, VF and SE tended to leave less residues on enamel surface than E&R. After thermocycling, the failure pattern changed significantly for VF and PAE/VF specimens that all exhibited adhesive failures at the tooth-bracket interface.
  
  
  CONCLUSIONS
  VF achieved early bracket SBSs similar to E&R. Following thermocycling, VF and PAE/VF manifested a significant decrease in SBS.
  
  
  CONCLUSIONS
  Although the simplified handling and the satisfactory early SBS of VF may prompt its use for bracket bonding, the decrease in retention noted after thermocycling warns that the issue of bond durability should be thoroughly addressed prior to endorsing this clinical application of VF.
authors.affiliation: Department of Dental Materials and Fixed Prosthodontics of University of Siena, Tuscan School of Dental Medicine, University of Firenze and Siena, Policlinico Le Scotte, viale Bracci, Siena 53100, Italy. cecilia.goracci@gmail.com
authors.forename: Cecilia
authors.initials: C
authors.lastname: Goracci
authors.forename: Mariam
authors.initials: M
authors.lastname: Margvelashvili
authors.forename: Agostino
authors.initials: A
authors.lastname: Giovannetti
authors.forename: Alessandro
authors.initials: A
authors.lastname: Vichi
authors.forename: Marco
authors.initials: M
authors.lastname: Ferrari
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000268:Adhesiveness; D003188:Composite Resins / Q000737:chemistry*; D055117:Curing Lights, Dental / Q000145:classification; D001840:Dental Bonding; D003743:Dental Enamel / Q000648:ultrastructure; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D055115:Light-Curing of Dental Adhesives; D016910:Orthodontic Brackets; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors
chemical_list: D003188:Composite Resins; D010756:Phosphoric Acids; D019279:Resin Cements; C429625:Transbond Plus Self-Etching Primer; C477790:Transbond XT; C516047:Transbond XT Light Cure Adhesive Primer; C581746:vertise flow; C030242:phosphoric acid