The purpose of this study was directed to evaluate the effects of different tooth
conditioning agents on shear bond strength of resin-modified glass– ionomer cement
(Fuji III LC) to enamel as well as on dissolution of calcium ions from the enamel surfaces.
Methods. The enamel surfaces of lower incisors were treated with 10 and 20%
polyacrylic acid, 12% citric acid and 35% phosphoric acid for 20s. Fuji III LC was
applied to the etched enamel surfaces, and the shear bond strength of each specimen
was measured using an Instron Universal Testing Instrument. The amounts of calcium
ions dissolved from the treated enamel surfaces were also measured using a polarized
Zeeman atomic absorptiometer. Results. In specimens pretreated with distilled water,
10% polyacrylic acid, 20% polyacrylic acid, 12% citric acid and 35% phosphoric acid,
the mean values of shear bond strength were 5.5, 12.5, 15.2, 15.2 and 15.1 MPa, respectively,
and the amounts of Ca2 dissolved from the enamel surfaces were 5.6, 41.4, 88.5,
131.6 and 588.3 mg/cm2,respectively. Conclusions. The adhesion of a resin-modified
glass–ionomer cement to enamel was significantly improved by the use of tooth-conditioning
agents. Especially, treatments of an enamel surface with 20% polyacrylic acid
results in good shear both strength and relatively small degree of enamel erosion.