title: Glass ionomer cements as luting agents for orthodontic brackets.
abstract: The objectives of the present study were to (1) assess the shear bond strengths of resin-reinforced glass ionomer Fuji Ortho LC and GC Fuji Ortho cements under differing conditions and (2) compare their bonding performance with that of conventional resin composite bonding systems. A sample of 264 bovine incisors was divided into 22 groups of 12 teeth each and bonded with SPEED central incisor brackets. Enamel surfaces of the teeth in the two experimental groups were conditioned according to the manufacturer's instructions; moreover, groups unconditioned before bonding were also included under both wet and dry conditions. A self-cure composite resin (Phase II) and a light-cure composite resin (Transbond XT) served as controls and were etched with 37% phosphoric acid and bonded in a dry field. After incubation at 37 degrees C for 24 hours and for seven days, the specimens were tested to failure with a shear force in an Instron machine. The Adhesive Remnant Index (ARI) was used to assess the amount of resin left on the enamel surfaces after debonding. Selected specimens were examined using scanning electron microscopy. Statistical analyses included analysis of variance tests, t-tests, and correlation coefficient calculations and showed that no significant difference existed between the glass ionomer cements under wet or dry conditions, provided the enamel was conditioned with 10% polyacrylic acid before bonding. Both glass ionomer cements were thus acceptable for bonding. Transbond XT had the highest mean shear bond strength irrespective of the incubation period. A positive correlation was obtained between the ARI scores and bond strength.
authors.affiliation: University of Toronto, Ontario.
authors.forename: K S
authors.initials: KS
authors.lastname: Coups-Smith
authors.forename: P E
authors.initials: PE
authors.lastname: Rossouw
authors.forename: K C
authors.initials: KC
authors.lastname: Titley
mesh_terms: D000134:Acid Etching, Dental; D000180:Acrylic Resins / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D000704:Analysis of Variance; D000818:Animals; D002417:Cattle; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003743:Dental Enamel / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D016910:Orthodontic Brackets; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors
chemical_list: D000180:Acrylic Resins; D000538:Aluminum Silicates; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C112133:Fuji Ortho; C095451:Fuji Ortho LC; D005899:Glass Ionomer Cements; D010756:Phosphoric Acids; D019279:Resin Cements; C477790:Transbond XT; C006903:carbopol 940