title: Effect of UVA-activated riboflavin on dentin bonding.
abstract: Recent studies have reported collagen cross-linking after exposure to riboflavin followed by ultraviolet-A (UVA) exposure. This study is the first to investigate the effect of a riboflavin-containing primer on adhesive interface stability and dentinal matrix metalloproteinase activity. Human dentin was etched with 35% phosphoric acid, treated with 0.1% riboflavin, exposed to UVA for 2 min, and bonded with a two-step etch-and-rinse adhesive. Adhesive was applied to control specimens without riboflavin/UVA. Specimens were subjected to microtensile bond strength tests and pulled to failure after storage for 24 hrs, 6 mos, or 1 yr. Interfacial nanoleakage was evaluated by light and transmission electron microscopy. To investigate dentinal matrix metalloproteinase activity, we performed correlative zymographic assays on protein extracts obtained from phosphoric-acid-etched dentin powder with or without riboflavin/UVA treatment and XP Bond. Ultraviolet-activated riboflavin treatment increased the immediate bond strength to dentin at all aging intervals (p < 0.05 vs. control) and decreased interfacial nanoleakage in aged specimens (1 yr; p < 0.05). Zymograms revealed that riboflavin/UVA pre-treatment inhibited dentinal matrix metalloproteinase activity (especially MMP-9). In conclusion, dentinal collagen cross-linking induced by riboflavin/UVA increased immediate bond strength, stabilized the adhesive interface, and inhibited dentin matrix metalloproteinases, thereby increasing the durability of resin-dentin bonds.
authors.affiliation: Department of SAU&FAL, University of Bologna, Via Irnerio, 48, 40100 Bologna, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Cova
authors.forename: L
authors.initials: L
authors.lastname: Breschi
authors.forename: F
authors.initials: F
authors.lastname: Nato
authors.forename: A
authors.initials: A
authors.lastname: Ruggeri
authors.forename: M
authors.initials: M
authors.lastname: Carrilho
authors.forename: L
authors.initials: L
authors.lastname: Tjäderhane
authors.forename: C
authors.initials: C
authors.lastname: Prati
authors.forename: R
authors.initials: R
authors.lastname: Di Lenarda
authors.forename: F R
authors.initials: FR
authors.lastname: Tay
authors.forename: D H
authors.initials: DH
authors.lastname: Pashley
authors.forename: A
authors.initials: A
authors.lastname: Mazzoni
mesh_terms: D024042:Collagen Type I / Q000737:chemistry; D003432:Cross-Linking Reagents; D001840:Dental Bonding / Q000379:methods*; D003763:Dental Leakage / Q000517:prevention & control; D003799:Dental Stress Analysis; D003804:Dentin / Q000201:enzymology*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods*; D006801:Humans; D061965:Matrix Metalloproteinase Inhibitors; D012256:Riboflavin / Q000528:radiation effects*; D013718:Tensile Strength; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D024042:Collagen Type I; D003432:Cross-Linking Reagents; D017220:Dentin-Bonding Agents; D061965:Matrix Metalloproteinase Inhibitors; C532387:XP-Bond; D012256:Riboflavin