title: Photodynamically crosslinked and chitosan-incorporated dentin collagen.
abstract: A lingering concern with restored root-filled teeth is the loss of structural integrity of the dentin and dentin-sealer interface over time. We hypothesized that crosslinking of dentin collagen with simultaneous incorporation of a biopolymer into collagen matrix would improve its structural stability. This study aimed to investigate the effects of combining chemical/photodynamic crosslinking of dentin collagen with the incorporation of carboxymethyl-chitosan (CMCS) on the resistance to enzymatic degradation and mechanical properties of dentin collagen. Ninety-six demineralized dentin collagen specimens (human, n = 72; and bovine, n = 24) were prepared and crosslinked chemically/ photodynamically, with/without CMCS. Glutaraldehyde and carbodiimides were used for chemical crosslinking, while rose Bengal activated with a non-coherent light (540 nm) at 20 J/cm(2) was applied for photodynamic crosslinking. The crosslinked human dentin collagen was subjected to chemical characterization, 7 days enzymatic degradation, and transmission electron microscopy (TEM), while the bovine dentin collagen was used for tensile-testing. Crosslinked collagen showed significantly higher resistance to enzymatic degradation (p < 0.01), stable ultrastructure, and increased tensile strength (p < 0.05). Crosslinking CMCS with collagen matrix as observed in the TEM further improved the mechanical properties of dentin collagen (p < 0.01). This study highlighted the possibility of improving the resistance and toughness of dentin collagen by chemically/photodynamically crosslinking collagen matrix with CMCS.
authors.affiliation: Discipline of Endodontics, Faculty of Dentistry, University of Toronto, 124 Edward Street, Toronto, ON M5G1G6, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Shrestha
authors.forename: S
authors.initials: S
authors.lastname: Friedman
authors.forename: A
authors.initials: A
authors.lastname: Kishen
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001704:Biopolymers / Q000378:metabolism*; D002234:Carbodiimides / Q000494:pharmacology; D002417:Cattle; D048271:Chitosan / Q000031:analogs & derivatives / Q000378:metabolism; D024042:Collagen Type I / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D017364:Collagenases / Q000378:metabolism; D003432:Cross-Linking Reagents; D003799:Dental Stress Analysis; D003804:Dentin / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D016326:Extracellular Matrix Proteins / Q000737:chemistry*; D005976:Glutaral / Q000494:pharmacology; D006801:Humans; D006868:Hydrolysis; D008027:Light; D055550:Protein Stability; D012389:Root Canal Obturation / Q000379:methods*; D018709:Statistics, Nonparametric; D013718:Tensile Strength
chemical_list: D001704:Biopolymers; D002234:Carbodiimides; D024042:Collagen Type I; D003432:Cross-Linking Reagents; D016326:Extracellular Matrix Proteins; C514968:carboxymethyl-chitosan; D048271:Chitosan; D017364:Collagenases; D005976:Glutaral