title: Occlusal loading and cross-linking effects on dentin collagen degradation in physiological conditions.
abstract: OBJECTIVE
  This study evaluated the ability of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) to improve the stability of demineralized dentin collagen matrices when subjected to mechanical cycling by means of Chewing Simulation (CS).
  
  
  METHODS
  Demineralized dentin disks were randomly assigned to four groups (N=4): (1) immersion in artificial saliva at 37°C for 30 days; (2) pre-treatment with 0.5 M EDC for 60 s, then stored as in Group 1; (3) CS challenge (50 N occlusal load, 30 s occlusal time plus 30 s with no load, for 30 days); (4) pre-treatment with 0.5 M EDC as in Group 2 and CS challenge as in Group 3. Collagen degradation was evaluated by sampling storage media for ICTP and CTX telopeptides.
  
  
  RESULTS
  EDC treated specimens showed no significant telopeptides release, irrespective of the aging method. Cyclic stressing of EDC-untreated specimens caused significantly higher ICTP release at day 1, compared to static storage, while by days 3 and 4, the ICTP release in the cyclic group fell significantly below the static group, and then remained undetectable from 5 to 30 days. CTX release in the cyclic groups, on EDC-untreated control specimens was always lower than in the static group in days 1-4, and then fell to undetectable for 30 days.
  
  
  CONCLUSIONS
  This study showed that chewing stresses applied to control untreated demineralized dentin increased degradation of collagen in terms of CTX release, while collagen crosslinking agents may prevent dentin collagen degradation, irrespective of simulated occlusal function.
authors.affiliation: Department of Medical Sciences, University of Trieste, Piazza dell'Ospitale 1, 34125 Trieste, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Turco
authors.affiliation: Department of Medical Sciences, University of Trieste, Piazza dell'Ospitale 1, 34125 Trieste, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Frassetto
authors.affiliation: Department of Medical Sciences, University of Trieste, Piazza dell'Ospitale 1, 34125 Trieste, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Fontanive
authors.affiliation: Department of Biomedical and Neuromotor Sciences, DIBINEM, University of Bologna, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Mazzoni
authors.affiliation: Department of Medical Sciences, University of Trieste, Piazza dell'Ospitale 1, 34125 Trieste, Italy.
authors.forename: Milena
authors.initials: M
authors.lastname: Cadenaro
authors.affiliation: Department of Medical Sciences, University of Trieste, Piazza dell'Ospitale 1, 34125 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, Italy. Electronic address: lorenzo.breschi@unibo.it.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Breschi
mesh_terms: D002234:Carbodiimides / Q000737:chemistry*; D024042:Collagen Type I / Q000378:metabolism*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D003799:Dental Stress Analysis; D003804:Dentin / Q000737:chemistry*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D066298:In Vitro Techniques; D008409:Mastication; D020782:Matrix Metalloproteinases / Q000737:chemistry; D008963:Molar; D010455:Peptides / Q000378:metabolism*; D012464:Saliva, Artificial; D013997:Time Factors
chemical_list: C518491:1-ethyl-3-(3-(diethylamino)propyl)carbodiimide; D002234:Carbodiimides; D024042:Collagen Type I; D003432:Cross-Linking Reagents; C093073:Demineralized Dentin Matrix; D010455:Peptides; D012464:Saliva, Artificial; C052929:collagen type I trimeric cross-linked peptide; D020782:Matrix Metalloproteinases
keywords: Collagen(s); Cross-linking agent; Demineralization; Dentin; Mastication Stress; Matrix metalloproteinases (MMPs)