Shear Bond Strength of Dentin Bonded to Various Restorative Materials Using Universal Resin Cements.

To evaluate the shear bond strengths and failure modes of dentin bonded to various restorative materials using three contemporary universal resin cements. Forty human third molars were longitudinally cut into 4 pieces. Ten sectioned were randomly divided into a group classified by bonding substrate materials and universal resin cement used. Two-mm diameter cylindrical rods were fabricated from five materials; Nickel-Chromium, Gold, Lithium disilicate glass ceramic, Zirconia, and Resin matrix ceramic. Three resin cements; Panavia V5, Duo-Link Universal, RelyX Universal were used to bond cylindrical specimens to prepared dentin surfaces according to the manufacturer's instructions. After subjected to thermocycling, shear bond strength was measured using a universal testing machine, and failure modes were assessed with a measuring microscope. Lithium disilicate glass ceramic displayed the highest bond strength of 36.14 MPa when bonded with Panavia V5, while Nickel-Chromium exhibited the highest bond strength of 38.02 MPa when bonded with Duo-Link Universal. The comparable bond strength could be obtained when using these two cements bonded Nickel-Chromium, Zirconia, and Lithium disilicate glass ceramic (p > 0.05). While, bonding to Gold and Resin matrix ceramic provided the inferior bond strength. No significant differences were found among all substrates when RelyX Universal cement was used (p > 0.05). The most common failure pattern was adhesive failure between restorative material and resin cement, followed by adhesive failure between dentin and resin cement. Gold and Resin matrix ceramic exhibited lower shear bond strength compared to the other materials, whereas Nickel-Chromium, Zirconia, and Lithium disilicate glass ceramic showed high shear bond strength when Panavia V5 and Duo-Link Universal were used. RelyX Universal showed lower shear bond strength than other cements and there were no significant differences among all substrates. [ABSTRACT FROM AUTHOR]