Surface pretreatments and erosive aging effects on the bond strength of CAD/CAM resin-based materials with a self-adhesive resin cement

This laboratory study evaluated the effect of surface pretreatments and erosion on the shear bond strength (SBS) of additive (3D-printed; Crowntec™) and subtractive (milled; Cerasmart™ 270) CAD/CAM resin-based materials bonded with a self-adhesive resin cement. Seventy-two specimens of each material were assigned to three surface pretreatment groups: control, grit-blasting, and grit-blasting + universal adhesive (UA). After treatment, self-adhesive resin cement (Panavia™ SA Cement Plus) was applied using a mold (2.38 mm diameter, 3 mm height). Specimens were then divided into control, gastric acid, and citric acid groups and subjected to 96 h erosive aging (n = 8). SBS was tested with a universal testing machine, failure modes were examined under a stereomicroscope, and data analyzed using SPSS 21.0 (α = 0.05). Material type and erosion significantly affected SBS (p < 0.001), whereas surface pretreatments did not (p = 0.698). Crowntec showed decreased SBS in the grit-blasting + UA group after gastric acid (p = 0.02), while Cerasmart had reduced SBS in all pretreated groups after both acids (p < 0.05). Overall, Crowntec exhibited higher SBS with predominant cohesive failures, while Cerasmart showed mainly adhesive failures, except in the grit-blasting + UA group. The findings indicate that SBS of self-adhesive resin cement to resin-based CAD/CAM materials depends on material type and erosive aging, while surface pretreatments mainly affect failure mode.