title: Effect of resin hydrophilicity on water-vapour permeability of dental adhesive films.
abstract: This study examined the water-vapour permeability of thin polymerized resin films fabricated from five co-monomer blends of increasing degrees of hydrophilicity, as measured by their Hoy's solubility parameters. Neat resin films were prepared from five experimental light-curable resins (n = 10). Each film was mounted in a Fisher permeability cup with 8 g of water placed inside the cup. The experiments were conducted in a modified twin-outlet desiccator connected to a vacuum pump in one outlet to permit a continuous airflow to encourage water evaporation. Weight losses by water evaporation were measured at 3, 6, 9, 24, 30, and 48 h by using an analytical balance. Additional resin films were examined by using transmission electron microscopy (TEM) after immersion in ammoniacal silver nitrate. A significant correlation was observed between the cumulative water loss at 48 h and the Hoy's total cohesive energy density (delta(t)). Transmission electron microscopy revealed silver-filled channels along film peripheries and silver grains of decreasing dimensions toward the film centres in co-monomer blends 3, 4, and 5 of increasing hydrophilicity. Hydrophilic dentin adhesives polymerized in thin films are prone to water loss by evaporation. This probably accounts for the water droplets seen on the surface of vital-bonded dentin after the application of simplified dentin adhesives.
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital, Pokfulam, Hong Kong SAR, China.
authors.forename: Nigel M
authors.initials: NM
authors.lastname: King
authors.forename: Noriko
authors.initials: N
authors.lastname: Hiraishi
authors.forename: Cynthia K Y
authors.initials: CK
authors.lastname: Yiu
authors.forename: Edna L
authors.initials: EL
authors.lastname: Pashley
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Loushine
authors.forename: Fred A
authors.initials: FA
authors.lastname: Rueggeberg
authors.forename: David H
authors.initials: DH
authors.lastname: Pashley
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Tay
mesh_terms: D017220:Dentin-Bonding Agents / Q000737:chemistry*; D003890:Desiccation; D006801:Humans; D007101:Immersion; D008422:Materials Testing; D046529:Microscopy, Electron, Transmission; D010539:Permeability; D019279:Resin Cements / Q000737:chemistry*; D016622:Silver Staining; D012995:Solubility; D013499:Surface Properties; D013997:Time Factors; D014835:Volatilization; D014867:Water / Q000737:chemistry*
chemical_list: D017220:Dentin-Bonding Agents; D019279:Resin Cements; D014867:Water