title: Nanoleakage of luting agents for bonding fiber posts after thermomechanical fatigue.
abstract: OBJECTIVE
  To investigate the depth of nanoleakage of four luting agents for bonding fiber posts after thermomechanical fatigue.
  
  
  METHODS
  Twenty-four extracted human anterior teeth were endodontically treated, sectioned at the cementoenamel junction, and restored with fiber posts using four commercially available resin cements with the corresponding core buildup materials (n = 6): Panavia F 2.0/Clearfil DC Core Automix (Kuraray), Variolink II/Multicore Flow (Ivoclar Vivadent), RelyX Unicem/Filtek Z250 (3M ESPE), and Multilink Sprint/Multicore Flow (Ivoclar Vivadent). The specimens received all-ceramic crowns and were subjected to thermomechanical fatigue (1.2 million cycles). After cutting off the crowns, the roots were isolated with nail polish except for a 1-mm rim around the root canal, and immersed in 50 wt% ammoniacal silver nitrate solution for 24 h. The specimens were sectioned perpendicular to the long axis of the tooth into four slices, fixed, dehydrated, and processed for FE-SEM. Leakage was analyzed using backscattered FE-SEM and EDS.
  
  
  RESULTS
  The depth of nanoleakage was significantly affected by the factor resin cement (p < 0.015; Kruskall-Wallis). Multilink Sprint resulted in significantly deeper penetration of silver particles than the other materials (p < 0.05; Mann Whitney U-Test).
  
  
  CONCLUSIONS
  Hybridization of the root canal dentin created by self-etching or etch-and-rinse adhesive systems demonstrated distinctive nanoleakage up to 0.8 mm, whereas the self-adhesive resin cement RelyX Unicem was able to prevent distinctive leakage at this penetration depth. However, none of the investigated luting systems would be able to hermetically seal the root canal if leakage occurred around the margins of the coronal restoration.
authors.affiliation: Department of Operative Dentistry and Periodontology, University School of Dental Medicine, CharitéCentrum 3, Charité-Universitätsmedizin Berlin, Germany. kerstin.bitter@charite.de
authors.forename: Kerstin
authors.initials: K
authors.lastname: Bitter
authors.forename: Jorge
authors.initials: J
authors.lastname: Perdigão
authors.forename: Christian
authors.initials: C
authors.lastname: Hartwig
authors.forename: Konrad
authors.initials: K
authors.lastname: Neumann
authors.forename: Andrej M
authors.initials: AM
authors.lastname: Kielbassa
mesh_terms: D002244:Carbon; D000077482:Carbon Fiber; D003188:Composite Resins; D001840:Dental Bonding; D003763:Dental Leakage / Q000209:etiology*; D003799:Dental Stress Analysis; D006801:Humans; D007180:Incisor; D008422:Materials Testing; D011176:Post and Core Technique; D019279:Resin Cements / Q000009:adverse effects*; D018709:Statistics, Nonparametric
chemical_list: D000077482:Carbon Fiber; D003188:Composite Resins; D019279:Resin Cements; D002244:Carbon