Effect of conditioning and 1 year aging on the bond strength and interfacial morphology of glass-ionomer cement bonded to dentin

Abstract Objective The purpose of this study was to determine the bond stability and the change in interfacial ultra-structure of a conventional glass-ionomer cement bonded to dentin, with and without pre-treatment using a polyalkenoic acid conditioner. Methods The occlusal dentin surfaces of six 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 specimens obtained were randomly assigned to two groups with different periods of storage in water: 1 week and 1 year. The micro-tensile 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 way as in the μTBS test. Results There was no significant difference in μTBS to conditioned dentin and non-conditioned dentin (p > 0.05). The failures appeared to be of a mixed nature, although aging caused more areas of cohesive than adhesive failure in both groups. The TEM observation showed an intermediate layer, a matrix-rich layer and a partially demineralized layer in the polyalkenoic acid conditioned group. Significance Aging did not reduce the bond strength of the conventional glass-ionomer cement to dentin with or without the use of a polyalkenoic acid conditioner.