Adhesive Performance of Ion-Releasing Materials on Dentin with Altered Mineralization

This study aimed to evaluate the ability of different categories of direct restorative materials to withstand artificial dentin alterations. A total of 360 human dentin specimens were allocated into 18 groups (n = 20). An ion-releasing bulk-fill resin-based composite (Cention Forte/CF), a resin-modified glass ionomer cement (Fuji II LC/FJLC), and an experimental conventional glass ionomer cement (EXP) were applied on sound, artificially hypermineralized, and demineralized dentin. Shear bond strength (SBS) was performed after 1 week and 6 months of storage, followed by fractographic analysis. Statistical analysis was performed using one- and three-way ANOVA, Games-Howell post hoc test, independent t-tests (α = 0.05), and Weibull analysis. SBS and bond reliability of CF on sound and hypermineralized dentin were higher than on other materials after both aging periods. On these two substrates, the SBS values of FJLC were higher than those of EXP, except for sound dentin after 6 months. Demineralized dentin significantly reduced the SBS of all materials under both aging conditions, with a high number of pre-test failures. The impact of aging was significant only in demineralized dentin for all materials. Ion-releasing resin-based composite performed best in terms of bond strength and reliability on sound and hypermineralized dentin. Artificially demineralized dentin severely compromised the bonding performance and maturation of all materials.