title: Effects of three restorative techniques in the bond strength and nanoleakage at gingival wall of Class II restorations subjected to simulated aging.
abstract: OBJECTIVE
  To evaluate the effects of simulated aging in bond strength and nanoleakage of class II restorations using three different restorative techniques.
  
  
  METHODS
  Class II preparations (n = 12) were restored using: FS - composite resin Filtek Supreme Plus (3M/ESPE); RMGIC + FS - resin-modified glass ionomer cement Vitrebond Plus (3M/ESPE) + FS; and FFS + FS - flowable composite resin Filtek Supreme Plus Flowable (3M ESPE) + FS. The teeth were assigned into two groups: Control and Simulated Aging - Thermal/Mechanical cycling (3,000 cycles, 20-80 °C/500,000 cycles, 50 N). From each tooth, two slabs were assessed to microtensile bond strength test (μTBS) (MPa), and two slabs were prepared for nanoleakage assessment, calculated as penetration along the restoration margin considering the penetration length (%) and as the area of silver nitrate particle deposition (μm(2)). Data were analyzed by two-way analysis of variance (ANOVA) followed by Tukey's post hoc test (p < 0.05).
  
  
  RESULTS
  FS presented the highest μTBS to dentin (22.39 ± 7.55 MPa) after simulated aging, while the presence of flowable resin significantly decreased μTBS (14.53 ± 11.65 MPa) when compared to no aging condition. Both control and aging groups of RMGIC + FS presented the highest values of silver nitrate penetration (89.90 ± 16.31 % and 97.14 ± 5.76 %) and deposition area (33.05 ± 12.49 and 28.08 ± 9.76 μm(2)). Nanoleakage was not affected by simulated aging.
  
  
  CONCLUSIONS
  FS presented higher bond strength and lower nanoleakage and was not affected by simulated aging. Use of flowable resin compromised the bond strength after simulated aging.
  
  
  CONCLUSIONS
  The use of an intermediate layer did not improve the dentin bond strength neither reduced nanoleakage at the gingival margins of class II restorations under simulated aging conditions.
authors.affiliation: Department of Restorative Dentistry, Aracatuba School of Dentistry, UNESP, Araçatuba, SP, Brazil. crismpvidal@gmail.com
authors.forename: Cristina
authors.initials: C
authors.lastname: de Mattos Pimenta Vidal
authors.forename: Sabrina
authors.initials: S
authors.lastname: Pavan
authors.forename: André Luiz Fraga
authors.initials: AL
authors.lastname: Briso
authors.forename: Ana Karina
authors.initials: AK
authors.lastname: Bedran-Russo
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000145:classification* / Q000295:instrumentation; D003763:Dental Leakage / Q000145:classification*; D003793:Dental Restoration, Permanent / Q000145:classification / Q000379:methods*; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D019279:Resin Cements / Q000737:chemistry; D016622:Silver Staining / Q000379:methods; D013314:Stress, Mechanical; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D003188:Composite Resins; C515951:Filtek Supreme Plus; D005899:Glass Ionomer Cements; D019279:Resin Cements; C511238:Single Bond Plus; C541368:Vitrebond Plus; D014867:Water; D017438:Bisphenol A-Glycidyl Methacrylate