title: Effect of long-term storage on nanomechanical and morphological properties of dentin-adhesive interfaces.
abstract: BACKGROUND
  To evaluate the influence of storage time on the elastic modulus, micromorphology, nanoleakage, and micromechanical behavior of the dentin-adhesive interfaces of five adhesive systems (Scotchbond Multi-Purpose, Clearfil SE Bond, One Up Bond F, Adper Easy One, and Filtek LS Adhesive) after 24h (T0) and 12 months (T1).
  
  
  METHODS
  Fifty teeth were restored and distributed according to each adhesive system (n=10). At least four specimens were obtained from each tooth. One specimen was evaluated under SEM to obtain the micromorphology of dentin-adhesive interface (DAI). Two specimens were used to assess nanoleakage, one tested in T0 and the other in T1. The last specimen was used for nanoindentation, in T0 and T1, to obtain the initial and final mechanical properties of DAI structures. Two non-restored teeth were evaluated under SEM to obtain the dentin morphology. Laboratorial data were used to build 15 finite element models to assess the maximum principal stress in each time of analysis.
  
  
  RESULTS
  Storage resulted in hydrolysis of the dentin-adhesive interfaces for all groups. Silver impregnation increased for all groups after 1 year storage (p<.05), except for Clearfil SE Bond. In general, a decrease in elastic modulus values was observed for all groups from T0 to T1 (p<.05), mainly at the hybrid layer. The FEAs showed higher stress levels at T1 than T0 simulations for all adhesives.
  
  
  CONCLUSIONS
  At T1, degradation occurred at the dentin-adhesive interface formed by all adhesives, and the intensity of degradation differed depending on the type of adhesive system used. The interface formed by the self-etching primer containing the 10-MDP functional monomer showed the highest stability among the adhesive systems after 12 months of storage.
authors.affiliation: Univ. Estadual Paulista-UNESP Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba, SP, Brazil; New York University, Department of Biomaterial and Biomimetics, New York, NY, USA. Electronic address: rodolfoanchieta2@hotmail.com.
authors.forename: Rodolfo Bruniera
authors.initials: RB
authors.lastname: Anchieta
authors.affiliation: Univ. Estadual Paulista -UNESP Araçatuba Dental School, Department of Restorative Dentistry, Araçatuba, SP, Brazil; New York University, Department of Biomaterial and Biomimetics, New York, NY, USA.
authors.forename: Lucas Silveira
authors.initials: LS
authors.lastname: Machado
authors.affiliation: Univ. Estadual Paulista-UNESP Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba, SP, Brazil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Martini
authors.affiliation: Univ. Estadual Paulista-UNESP Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba, SP, Brazil; Univ. Estadual Paulista -UNESP Araçatuba Dental School, Department of Restorative Dentistry, Araçatuba, SP, Brazil.
authors.forename: Paulo Henrique dos
authors.initials: PH
authors.lastname: Santos
authors.affiliation: Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Giannini
authors.affiliation: New York University, Department of Biomaterial and Biomimetics, New York, NY, USA.
authors.forename: Malvin
authors.initials: M
authors.lastname: Janal
authors.affiliation: New York University, Department of Biomaterial and Biomimetics, New York, NY, USA.
authors.forename: Nick
authors.initials: N
authors.lastname: Tovar
authors.affiliation: Univ. Estadual Paulista -UNESP Araçatuba Dental School, Department of Restorative Dentistry, Araçatuba, SP, Brazil.
authors.forename: Renato Herman
authors.initials: RH
authors.lastname: Sundfeld
authors.affiliation: Univ. Estadual Paulista-UNESP Araçatuba Dental School, Department of Dental Materials and Prosthodontics, Araçatuba, SP, Brazil.
authors.forename: Eduardo Passos
authors.initials: EP
authors.lastname: Rocha
authors.affiliation: New York University, Department of Biomaterial and Biomimetics, New York, NY, USA.
authors.forename: Paulo G
authors.initials: PG
authors.lastname: Coelho
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003763:Dental Leakage; D003764:Dental Materials / Q000737:chemistry; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D055119:Elastic Modulus; D020342:Finite Element Analysis; D066298:In Vitro Techniques; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors
chemical_list: C000612360:Adper Easy One; C438313:Clearfil SE Bond; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C543062:Filtek LS Low Shrink resin; D008689:Methacrylates; C446260:One-Up-Bond F; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; D017438:Bisphenol A-Glycidyl Methacrylate
keywords: Dentin; Dentin–adhesive interface; Hybrid layer; Hydrolytic degradation; Mechanical properties