Evaluation of Shear Bond Strength of Lithium Disilicate Veneers Using Pre-heated Resin Composite With Two Conventional Resin Cements: An In Vitro Study

Objectives This study aimed to compare the shear bond strength of three resin cements (light-cured resin cement, pre-heated composite resin, and dual-cured self-adhesive resin cement) when bonding to lithium disilicate discs. Materials and methods Thirty-six discs made of lithium disilicate were fabricated and etched with 9.5% (HF), and 36 human premolars were collected and immersed in the acrylic molds, then randomly divided into three equal groups (n = 12): Group 1: light-cured resin cement, Group 2: pre-heated resin composite, and Group 3: dual-cured resin cement. The resin composite was heated between 55°C and 65°C by a heater device. The shear bond strength test was performed using the general mechanical testing device. The data were analyzed using two-way ANOVA and Bonferroni tests (p < 0.05). Results The highest shear bond strength was demonstrated by the light-cured resin cement group (26.61 ± 5.16 Mpa), followed by the dual-cured resin cement group (17.76 ± 4.67 Mpa), and the least by the pre-heated composite resin group (15.58 ± 3.36 MPa). The shear bond strength in the light-cured resin cement group was significantly higher than the dual-cured resin cement and pre-heated composite resin groups. Conclusion The light-cured resin cement has higher shear bond strength when compared to pre-heated resin composite and dual-cured resin cement with a self-etch system. Although pre-heating composite resins may increase its mechanical proprieties and make it suitable for luting ceramics it may not increase bond strength.