Preserving the strength and durability of dentin bonds is a concern of dental researchers and practitioners.


The aim of this study was to investigate the effect of treating etched dentin with vitamin C and curcumin suspension as cross-linking agents on the shear bond strength and durability of a universal dental adhesive.


Extracted human third molar teeth were collected. Fifty-six flat coronal dentin surfaces were divided equally into four groups: (1) treated with adhesives; (2) etched with 37% H3PO4 for 10s before application of adhesives; (3) same as group (2), but with dentin treated with 2.5% curcumin suspension for 60s before the application of adhesive; and (4) same as group (3), but with the use of a 20% vitamin C suspension instead of a curcumin suspension. Filtek Z350XT composite was built for all samples. Half of the samples in each group were subjected to thermocycling. Shear bond strength was measured using a universal testing machine. Scanning electron microscopy was used to investigate the dentinal surfaces after treatment.


Treatment with curcumin suspension preserved immediate and long-term bond strength. Conversely, treatment of etched dentin with vitamin C solution significantly reduced the immediate bond strength, but a significant improvement was observed after aging. SEM showed that both cross-linking agents resulted in narrowing or closing of the dentinal tubules, with an adhesive mode of failure.


The application of curcumin or vitamin C suspension to acid-etched dentin resulted in different effects on immediate and long-term shear bond strength when using universal adhesives.

Keywords: Curcumin suspension, Vitamin C, Dentin cross-linking, Hydrolytic degradation, Shear bond strength, Universal dental adhesive.
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