The effect of different adhesive strategies and diamond burs on dentin bond strength of universal resin cements

Objectives: To evaluate the shear bond strength (SBS) of universal cements (UCs) to dentin prepared with different diamond burs using various adhesive strategies.

Materials and methods: One-hundred-twenty molars were prepared to expose the mid-coronal dentin. The teeth were divided into two groups according to diamond bur preparations: coarse and super-fine grit burs. The specimens were bonded to lithium disilicate discs using two UCs (RelyX Universal, RXU and Panavia SA Luting Multi, PSA) with different adhesive strategies (self-adhesive, SA; self-etch, SE and etch-and-rinse, ER). SBS was measured using a universal testing machine. The cement-dentin interfaces were observed using scanning electron microscopy.

Results: Dentin SBS was significantly influenced by the adhesive strategies and the type of UCs (p < 0.05) but not for the different diamond bur preparations (p > 0.05). UCs used with ER had significantly higher SBS values than UCs used in SA mode (P < 0.05), except for PSA with super-fine diamond bur. RXU in SE mode exhibited significantly higher SBS than SA mode (P < 0.05). Regarding UCs, RXU showed a higher SBS than PSA, particularly in the SE modes when the dentin was prepared with a coarse diamond bur (P < 0.05).

Conclusion: The use of UCs combined with universal adhesives exhibited higher dentin bonding performance compared with the use of UCs alone.

Clinical significance: The etch-and-rinse mode combined with a universal adhesive is recommended to achieve the highest dentin bond strength of universal cements.