The Effect of Water Aging on the Repair Shear Bond Strength of Current Resin Composites

Aims: We aimed to examine if water aging changes the repair bond strength of currently available resin composites. Subjects and Methods: Charisma (Kulzer, Hanau, Germany), Essentia (GC, Tokyo, Japan), and CeramX (Dentsply Sirona, North Carolina, USA) resin composites were prepared within acrylic resin cylinders (n = 22). The surfaces of all samples were polished with OptiDisc (Kerr, California, USA), and G-Premio BOND (GC, Tokyo, Japan) was applied to the surfaces. The G-aenial (GC, Tokyo, Japan) resin composite was formed on the adhesive-applied surface aided by a Teflon mold with a diameter of 2.38 mm and height of 2 mm and then polymerized with a LED light source (VALO Cordless, Standard mode; Ultradent, Utah, USA) for 20 s. All samples were kept in water for 1 day. To determine the shear bond strength, a universal test device (Marestek, İstanbul, Turkey) with a knife-edged metal tip was used at a speed of 1 mm/min. For the experimental group, the composite surfaces of the same samples were sanded with 180-grit silicon carbide sandpaper and then polished with OptiDisc (Kerr, California, USA). Samples were then kept in water for 6 months. Adhesive repair resin composite and shear test applications were performed similarly to the control group. Paired sample t-test, one-way ANOVA, and post hoc Tukey’s Honestly Significant Difference tests were performed for statistical analysis. For statistical significance, P < 0.05 was accepted. Results: We observed repair shear bond strength values of 7.88 ± 3.20 MPa for Charisma versus 5.64 ± 3.08 MPa aged Charisma, 7.65 ± 2.64 MPa for Essentia versus 5.67 ± 3.10 MPa for aged Essentia, and 7.07 ± 3.22 MPa for CeramX versus 4.80 ± 2.28 for MPa aged CeramX. There was no difference within control groups nor in aged groups (P > 0.05). However, bond strength was lower in aged composites (P < 0.05). Conclusions: The repair bond strength of current resin composites decreases after 6 months of water aging.