title: Effect of carboidiimide on thermal denaturation temperature of dentin collagen.
abstract: OBJECTIVE
  1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) has been shown to cross-link dentin type I collagen. Increased cross-linking usually elevates the glass transition temperature of polymers. The aim of this study was to evaluate the cross-linking reaction promoted by EDC in different aqueous concentrations by measuring the thermal denaturation temperature (Td) of human dentin collagen.
  
  
  METHODS
  The Td of dehydrated collagen and of insoluble dentin matrix collagen immersed in 0.5M or 1M EDC aqueous solution for different treatment times was obtained using a Differential Scanning Calorimeter (DSC). Specimens were also analyzed by Energy Dispersive X-Ray Spectroscopy.
  
  
  RESULTS
  EDC-treated dentin collagen showed a significantly higher Td than the untreated specimens when immersed in either 0.5M EDC or 1M EDC for 10min or longer (p<0.05). EDC-treated dentin collagen showed an increase of sulfur and chloride, not detectable in EDC-untreated dentin specimens. Conversely, the relative amount of carbon, nitrogen and oxygen was not modified by treatments.
  
  
  CONCLUSIONS
  EDC-treated dentin collagen showed a higher Td than the untreated control at all tested concentrations and immersion times. A higher Td can be considered an indirect indicator of a more resistant and highly cross-linked collagen network. More data are needed to confirm these results.
authors.affiliation: Department of Medical Sciences, University of Trieste, Piazza dell'Ospitale 1, I-34129 Trieste, Italy. Electronic address: mcadenaro@units.it.
authors.forename: Milena
authors.initials: M
authors.lastname: Cadenaro
authors.affiliation: Department of Medical Sciences, University of Trieste, Piazza dell'Ospitale 1, I-34129 Trieste, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Fontanive
authors.affiliation: Department of Medical Sciences, University of Trieste, Piazza dell'Ospitale 1, I-34129 Trieste, Italy.
authors.forename: Chiara Ottavia
authors.initials: CO
authors.lastname: Navarra
authors.affiliation: Department of Earth, Life and Environment Sciences (Di.STeVA), University of Urbino, Campus Scientifico Enrico Mattei - Via Ca' Le Suore 2/4, I-61029 Urbino (PU), Italy.
authors.forename: Pietro
authors.initials: P
authors.lastname: Gobbi
authors.affiliation: Department of Biomedical and Neuromotor Sciences, DIBINEM, University of Bologna, Via San Vitale 59, I-40125 Bologna, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Mazzoni
authors.affiliation: Department of Medical Sciences, University of Trieste, Piazza dell'Ospitale 1, I-34129 Trieste, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Di Lenarda
authors.affiliation: Department of Oral Biology, Georgia Regents University, College of Dental Medicine, Augusta, GA, USA.
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Tay
authors.affiliation: Department of Oral Biology, Georgia Regents University, College of Dental Medicine, Augusta, GA, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Pashley
authors.affiliation: Department of Biomedical and Neuromotor Sciences, DIBINEM, University of Bologna, Via San Vitale 59, I-40125 Bologna, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Breschi
mesh_terms: D002151:Calorimetry; D002234:Carbodiimides / Q000737:chemistry*; D003094:Collagen / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D003804:Dentin / Q000737:chemistry*; D006801:Humans; D044367:Phase Transition; D013052:Spectrometry, X-Ray Emission; D013696:Temperature
chemical_list: D002234:Carbodiimides; D003432:Cross-Linking Reagents; D003094:Collagen
keywords: Collagen; Cross-linking; Differential scanning calorimetry; EDC; Thermal denaturation