title: An in vitro comparison of the shear bond strength of a resin-reinforced glass ionomer cement and a composite adhesive for bonding orthodontic brackets.
abstract: The shear bond strength (SBS) of a light-cured, resin-reinforced glass ionomer and a composite adhesive in combination with a self-etching primer was compared after different setting times to evaluate when orthodontic wires could be placed. Additionally, the fracture site after debonding was assessed using the Adhesive Remnant Index (ARI). Eighty freshly extracted human premolars were used. Twenty teeth were randomly assigned to each of four groups: (1) brackets bonded with Transbond XT with a Transbond Plus etching primer and debonded within 5 minutes; (2) brackets bonded with Fuji Ortho LC and debonded within 5 minutes; (3) brackets bonded as for group 1 and debonded within 15 minutes; (4) brackets bonded as for group 2 and debonded within 15 minutes. The SBS of each sample was determined with an Instron machine. The mean SBS were, respectively: (1) 8.8 +/- 2 MPa; (2) 6.6 +/- 2.5 MPa; (3) 11 +/- 1.6 MPa and (4) 9.6 +/- 1.6 MPa. Interpolating the cumulative fracture probability by means of a Weibull analysis, the 10 per cent probabilities of fracture for the groups were found to be attained for shear stresses of 6.1, 3.1, 8.3 and 7.1 MPa, respectively. Chi-square testing of the ARI scores revealed that the nature of the remnant did not vary significantly with time, but the type of bonding material could generally be distinguished in leaving more or less than 10 per cent of bonding material on the tooth. After debonding, the Transbond system was likely to leave adhesive on at least 10 per cent of the bonded area of the tooth. The present findings indicate that brackets bonded with either Transbond XT in combination with Transbond Plus etching primer and Fuji Ortho LC had adequate bond strength at 5 minutes and were even stronger 15 minutes after initial bonding.
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, University of Oslo, Norway .
authors.forename: Hassan Z
authors.initials: HZ
authors.lastname: Movahhed
authors.forename: Bjørn
authors.initials: B
authors.lastname: Ogaard
authors.forename: Morten
authors.initials: M
authors.lastname: Syverud
mesh_terms: D000180:Acrylic Resins; D000538:Aluminum Silicates; D001641:Bicuspid; D016009:Chi-Square Distribution; D001840:Dental Bonding / Q000379:methods*; D003799:Dental Stress Analysis; D005899:Glass Ionomer Cements; D006801:Humans; D008422:Materials Testing; D016910:Orthodontic Brackets; D011897:Random Allocation; D019279:Resin Cements; D033081:Shear Strength; D018709:Statistics, Nonparametric; D016019:Survival Analysis
chemical_list: D000180:Acrylic Resins; D000538:Aluminum Silicates; C095451:Fuji Ortho LC; D005899:Glass Ionomer Cements; D019279:Resin Cements; C429625:Transbond Plus Self-Etching Primer; C477790:Transbond XT