title: Effects of N-methacryloyl amino acid applications on hybrid layer formation at the interface of intertubular dentin.
abstract: To understand the role of NMAA in the bonding of composite resin to a dentin surface, we investigated the effects of N-methacryloyl amino acid (NMAA) application on the expansion of aggregated collagen fibers, formation of a hybrid layer, and the tensile bond strength between composite resin and dentin. Four NMAA derivatives--N-methacryloyl-alpha-glycine (NMGly), N-methacryloyl-gamma-amino n-butyric acid (NMBu), N-methacryloyl-alpha-hydroxyproline (NMHPro), and N-methacryloyl-alpha-glutamic acid (NMGlu)--were prepared and applied to dentin surfaces which had been etched with 40% by mass H3PO4 and air-blown. The shrunken collagenous layer expanded by approximately 50% to 70% by volume of the original collagenous layer thickness after application of the NMAA primers. Application of the bonding agent and composite resin after NMAA treatment resulted in the formation of a hybrid layer. The thickness of the hybrid layer was somewhat smaller than the collagenous layer formed by the NMAA treatment only, regardless of the type of NMAA used. The thickness of the hybrid layer was approximately ten times larger than that formed without NMAA treatment. Although all NMAA primers formed hybrid layers of similar thickness, higher tensile bond strengths, from 13 to 15 MPa, were obtained when etched and air-blown dentin was treated with NMBu, NMGly, or NMGlu. NMHPro gave only 6.6 MPa, a value similar to that obtained when no NMAA was used. We concluded, therefore, that formation of the hybrid layer is a necessary but insufficient condition for high bond strength.
authors.affiliation: Department of Biomaterials, Okayama University Dental School, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
authors.forename: N
authors.initials: N
authors.lastname: Nishiyama
authors.forename: K
authors.initials: K
authors.lastname: Nemoto
authors.forename: Y
authors.initials: Y
authors.lastname: Torii
authors.forename: K
authors.initials: K
authors.lastname: Inoue
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002087:Butyrates / Q000032:analysis / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D002417:Cattle; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000032:analysis / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D018698:Glutamic Acid / Q000031:analogs & derivatives* / Q000032:analysis / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D005998:Glycine / Q000031:analogs & derivatives* / Q000032:analysis / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D008689:Methacrylates / Q000032:analysis / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D008855:Microscopy, Electron, Scanning; D011392:Proline / Q000031:analogs & derivatives* / Q000032:analysis / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D016369:Smear Layer; D013329:Structure-Activity Relationship; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D002087:Butyrates; D017220:Dentin-Bonding Agents; D008689:Methacrylates; C115674:N-methacryloyl-glutamic acid; C115673:N-methacryloyl-hydroxyproline; C115672:N-methacryloyl-n-butyric acid; C093041:N-methacryloyl glycine; D018698:Glutamic Acid; D011392:Proline; D005998:Glycine