title: Bond Strength of a Flowable Bulk-fill Resin Composite in Class II MOD Cavities.
abstract: OBJECTIVE
  To evaluate the microtensile bond strength (μTBS) of a bulk-fill low-stress resin-based composite to dentin from gingival walls of Class II MOD cavities.
  
  
  METHODS
  Class II MOD cavities were prepared in 44 human molars with the distal and mesial proximal boxes 4 and 6 mm deep, respectively. Eight experimental groups (n = 11) were obtained by a factorial design including 1. "composite" in two levels: a bulk-fill low-stress composite (SureFil SDR Flow, Dentsply Caulk) and a conventional composite (Filtek Z350 XT, 3M ESPE); 2. "filling technique" in two levels: bulk-fill (Bf) and incremental (In); and 3. "depth" in two levels: 4 mm and 6 mm in order to create different polymerization conditions. Twenty-four hours after placement of restorations, teeth were sectioned into beams with a cross-sectional bonded area of approximately 1 mm2. Bonded beams obtained from the gingival walls of the proximal boxes were tested in tension at a crosshead speed of 1 mm/min. Data were submitted to a 3-way ANOVA followed by a post-hoc Tukey's test (p < 0.05).
  
  
  RESULTS
  ANOVA failed to identify significant differences for the triple and double interaction between factors. However, significant differences were observed for the factors "composite" and "filling technique" (p < 0.05). SDR presented significantly higher μTBS values for bulk and incremental filling techniques (p < 0.05), and the incremental filling technique presented significantly higher μTBS values for both composites (p < 0.05).
  
  
  CONCLUSIONS
  It can be concluded that the bulk-fill flowable composite SDR may improve the bond strength to the gingival walls of Class II MOD cavities.
authors.forename: Rose Yakushijin
authors.initials: RY
authors.lastname: Kumagai
authors.forename: Leonardo Colombo
authors.initials: LC
authors.lastname: Zeidan
authors.forename: Jose Augusto
authors.initials: JA
authors.lastname: Rodrigues
authors.forename: André Figueiredo
authors.initials: AF
authors.lastname: Reis
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Roulet
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D003188:Composite Resins / Q000737:chemistry*; D055117:Curing Lights, Dental; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000145:classification*; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008434:Matrix Bands; D053761:Nanocomposites / Q000737:chemistry; D058105:Polymerization; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C553871:Surefil SDR Flow; C532387:XP-Bond; C533204:filtek Z350