title: Effect of carbodiimide (EDC) on the bond stability of etch-and-rinse adhesive systems.
abstract: OBJECTIVE
  Recent studies supported the use of protein cross-linking agents during bonding procedures to inactivate endogenous dentin proteases, preventing dentin collagen degradation thus improving bond durability. The aim of this study was to evaluate the effect of a 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-containing conditioner on the stability of the adhesive interface created by two etch-and-rinse adhesives.
  
  
  METHODS
  Human dentin was etched with 35% phosphoric acid, treated with 0.3M EDC-containing conditioner followed by a three-step or a two-step etch-and-rinse adhesive. Adhesives were applied to control specimens without EDC pre-treatment. Specimens were subjected to microtensile bond strength test and pulled to failure after 24h or 1 year of storage and interfacial nanoleakage expression was evaluated and quantified by light microscopy. Additionally, to investigate endogenous dentin matrix metalloproteinase activity a zymographic assay was performed on protein extracts obtained from phosphoric-acid-etched dentin powder with or without EDC treatment.
  
  
  RESULTS
  The use of the EDC-containing conditioner did not affect immediate bond strength to dentin but contributed to preserve the bond strength after 1 year (p<0.05) for both tested adhesives. No difference was found in the interfacial nanoleakage expression that increased after aging irrespective from the treatment. EDC pre-treatment inhibited dentin endogenous MMPs as assayed with the zymography.
  
  
  CONCLUSIONS
  In conclusion, the results of the study provide proof that EDC can produce long-term inactivation of MMPs in acid-etched dentin matrices contributing to bond strength preservation over time. Future studies are needed to support the use of EDC in vivo.
authors.affiliation: Department of Medical Sciences, University of Trieste, Trieste, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Mazzoni
authors.forename: Valeria
authors.initials: V
authors.lastname: Angeloni
authors.forename: Fabianni M
authors.initials: FM
authors.lastname: Apolonio
authors.forename: Nicola
authors.initials: N
authors.lastname: Scotti
authors.forename: Leo
authors.initials: L
authors.lastname: Tjäderhane
authors.forename: Arzu
authors.initials: A
authors.lastname: Tezvergil-Mutluay
authors.forename: Roberto
authors.initials: R
authors.lastname: Di Lenarda
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Tay
authors.forename: David H
authors.initials: DH
authors.lastname: Pashley
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Breschi
mesh_terms: D002234:Carbodiimides / Q000737:chemistry*; D003738:Dental Cements / Q000737:chemistry*; D008422:Materials Testing; D013718:Tensile Strength
chemical_list: D002234:Carbodiimides; D003738:Dental Cements
keywords: Dentin bonding systems; EDC; Enzymatic degradation; MMPs; Protein cross-linkers