Effect of Conditioning and Aging on the Bond Strength and Interfacial Morphology of Glass-ionomer Cement Bonded to Dentin.

PURPOSE

To determine the bond stability and the change in interfacial ultrastructure of a conventional glassionomer cement bonded to dentin, with and without pretreatment using a polyalkenoic acid conditioner.

MATERIALS AND METHODS

The occlusal dentin surfaces of 10 teeth were ground flat. Glass-ionomer cement was bonded to the surfaces either with or without polyalkenoic acid conditioning. The teeth were sectioned into 1-mm2 stick-shaped specimens. The 200 specimens obtained were randomly assigned to four groups with different periods of storage in water: 1 week, 1 month, 3 months, and 6 months. The microtensile bond strength (μTBS) was determined for each storage time. Additional specimens were prepared for transmission electron microscopy (TEM); they were produced with or without prior polyalkenoic acid conditioning in the same manner as for the μTBS test.

RESULTS

There was no significant difference in μTBS to conditioned dentin (p > 0.05). After 6 months of aging, the μTBS to non-conditioned dentin was significantly reduced as compared to the 1-week, 1-month, and 3-month results (p < 0.05). The failures appeared to be of a mixed nature, although aging caused more areas of cohesive than adhesive failure in all groups. TEM observation showed a demineralized layer and an amorphous gel phase in the polyalkenoic acid conditioned group.

CONCLUSION

Aging did not reduce the bond strength of the conventional glass-ionomer cement to dentin when the surface was pretreated with a polyalkenoic acid conditioner.