Bond strength of glass-ionomer cements to caries-affected dentin.
OBJECTIVE
The aim of this study was to assess the tensile bond strength of a resin-modified glass-ionomer cement (a: Fuji II LC) and three traditional glass-ionomer cements (b: Ketac-fil; c: Ketac Molar; d: Fuji IX) to caries-affected dentin.


METHODS
Forty human permanent molars with occlusal caries in dentin were selected, embedded in polyester resin, and ground until the carious dentin was exposed. Infected dentin was removed with curettes according to the atraumatic restorative technique (ART), and the tooth surface was smoothed with SiC paper. A bonding site, limited to 3 mm in diameter, was treated with polyacrylic acid for 10 s. After surface treatment, an inverted glass-ionomer cone was prepared for each specimen, using a split bisected Teflon matrix. The cones were immediately protected with a thin layer of nail varnish or bonding agent. Specimens were stored in distilled water at 37 degrees C for 24 h, and then bond strength to failure was tested.


RESULTS
The mean (SD) bond strengths in MPa were: a: 8.33 (2.35); b: 2.46 (1.60); c: 0.83 (1.18), and d: 1.45 (1.70). The data were analyzed using ANOVA and Tukey statistical tests. Fuji II LC, a resin-modified glass-ionomer cement, showed higher bond strength values and was statistically superior to the other groups, containing traditional glass ionomer cements (p < 0.05).


CONCLUSIONS
Findings showed that the traditional glass-ionomer cements tested in this study had lower mean bond strength values to caries-affected dentin than did the resin-modified glass-ionomer cement.
Department of Restorative Dentistry, Ribeirão Preto School of Dentistry, University of São Paulo, Ribeirão Preto-SP, Brazil. rgpalma@forp.usp.br
Regina Guenka
RG
Palma-Dibb
Carla Gregório
CG
de Castro
Renata Pereira
RP
Ramos
Daniela Thomazatti
DT
Chimello
Michelle Alexandra
MA
Chinelatti
D000134:Acid Etching, Dental; D000180:Acrylic Resins / Q000737:chemistry; D000704:Analysis of Variance; D001840:Dental Bonding; D003731:Dental Caries / Q000473:pathology*; D003737:Dental Cavity Preparation / Q000295:instrumentation / Q000379:methods; D003804:Dentin / Q000648:ultrastructure*; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006801:Humans; D008298:Maleates / Q000737:chemistry; D008422:Materials Testing; D019279:Resin Cements / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry; D013314:Stress, Mechanical; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
D000180:Acrylic Resins; C079765:Fuji II LC cement; D005899:Glass Ionomer Cements; D008298:Maleates; D019279:Resin Cements; D012117:Resins, Synthetic; C110713:fuji IX; C110712:ketac-molar; D014867:Water; C006903:carbopol 940; C040964:Ketac-Fil