title: Polymer nanocarriers for dentin adhesion.
abstract: To obtain more durable adhesion to dentin, and to protect collagen fibrils of the dentin matrix from degradation, calcium- and phosphate-releasing particles have been incorporated into the dental adhesive procedure. The aim of the present study was to incorporate zinc-loaded polymeric nanocarriers into a dental adhesive system to facilitate inhibition of matrix metalloproteinases (MMPs)-mediated collagen degradation and to provide calcium ions for mineral deposition within the resin-dentin bonded interface. PolymP- N : Active nanoparticles (nanoMyP) were zinc-loaded through 30-minute ZnCl2 immersion and tested for bioactivity by means of 7 days' immersion in simulated body fluid solution (the Kokubo test). Zinc-loading and calcium phosphate depositions were examined by scanning and transmission electron microscopy, elemental analysis, and x-ray diffraction. Nanoparticles in ethanol solution infiltrated into phosphoric-acid-etched human dentin and Single Bond (3M/ESPE) were applied to determine whether the nanoparticles interfered with bonding. Debonded sticks were analyzed by scanning electron microscopy. A metalloproteinase collagen degradation assay was also performed in resin-infiltrated dentin with and without nanoparticles, measuring C-terminal telopeptide of type I collagen (ICTP) concentration in supernatants, after 4 wk of immersion in artificial saliva. Numerical data were analyzed by analysis of variance (ANOVA) and Student-Newman-Keuls multiple comparisons tests (p < .05). Nanoparticles were effectively zinc-loaded and were shown to have a chelating effect, retaining calcium regardless of zinc incorporation. Nanoparticles failed to infiltrate demineralized intertubular dentin and remained on top of the hybrid layer, without altering bond strength. Calcium and phosphorus were found covering nanoparticles at the hybrid layer, after 24 h. Nanoparticle application in etched dentin also reduced MMP-mediated collagen degradation. Tested nanoparticles may be incorporated into dental adhesive systems to provide the appropriate environment in which dentin MMP collagen degradation is inhibited and mineral growth can occur.
authors.affiliation: Dental School, University of Granada, Colegio Maximo, Campus de Cartuja s/n, 18017 Granada, Spain rosorio@ugr.es.
authors.forename: R
authors.initials: R
authors.lastname: Osorio
authors.affiliation: Dental School, University of Granada, Colegio Maximo, Campus de Cartuja s/n, 18017 Granada, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Osorio
authors.affiliation: NanoMyP, Spin-Off Enterprise from University of Granada, Edificio BIC-Granada, Av. Innovación 1, 18016 Armilla, Granada, Spain.
authors.forename: A L
authors.initials: AL
authors.lastname: Medina-Castillo
authors.affiliation: Dental School, University of Granada, Colegio Maximo, Campus de Cartuja s/n, 18017 Granada, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Toledano
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002130:Calcium Phosphates / Q000493:pharmacokinetics; D002614:Chelating Agents / Q000737:chemistry; D024042:Collagen Type I / Q000032:analysis; D003188:Composite Resins / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods*; D003804:Dentin / Q000378:metabolism / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D004577:Electron Probe Microanalysis; D006801:Humans; D061965:Matrix Metalloproteinase Inhibitors / Q000494:pharmacology; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry*; D010455:Peptides / Q000032:analysis; D010756:Phosphoric Acids / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D012464:Saliva, Artificial / Q000737:chemistry; D013314:Stress, Mechanical; D014961:X-Ray Diffraction; D015032:Zinc / Q000737:chemistry*
chemical_list: D002130:Calcium Phosphates; D002614:Chelating Agents; D024042:Collagen Type I; D003188:Composite Resins; D003432:Cross-Linking Reagents; D017220:Dentin-Bonding Agents; D061965:Matrix Metalloproteinase Inhibitors; D008689:Methacrylates; D010455:Peptides; D010756:Phosphoric Acids; D011108:Polymers; D012464:Saliva, Artificial; C501891:Tetric EvoCeram; C052929:collagen type I trimeric cross-linked peptide; C115612:single bond; C008384:methacrylic acid; D017438:Bisphenol A-Glycidyl Methacrylate; C005044:hydroxyethyl methacrylate; C004919:ethylene dimethacrylate; C020243:calcium phosphate; C030242:phosphoric acid; D015032:Zinc
keywords: adhesives; dental; hybrid layer; nanopolymers; remineralization; zinc