Effect of different surface treatments on the bond strength of zirconia to resin cement. An in vitro study

Introduction Achieving a durable and stable bond between zirconium dioxide (zirconia) and resin cement remains a significant clinical challenge. This study aimed to investigate the effects of two novel zirconia surface treatments on the shear bond strength (SBS) between zirconia and resin cement following thermocycling. Methods Seventy-five CAD/CAM zirconia specimens (8 × 10 × 8 mm) were fabricated and randomly assigned to five groups ( n = 15): control (no treatment); air particle abrasion (APA); Zircos-E etching; APA+Zircos-E; Biomic LiSi Connect. All specimens were bonded using a zirconia primer, adhesive system, and dual-cure resin cement, except for Biomic LiSi Connect, which did not receive the zirconia primer treatment. Subsequently, all specimens underwent thermo-cycling. SBS was measured, and failure modes were classified. Statistical analysis revealed significant differences in SBS among the groups ( p < 0.001). Results and Discussion Zircos-E etching, APA+Zircos-E and Biomic LiSi Connect exhibited significantly higher bond strength than the control, with Biomic LiSi Connect demonstrating the highest mean SBS ( p < 0.001). Failure mode analysis showed no statistically significant differences among groups. Both Zircos-E and Biomic LiSi Connect significantly enhanced the bond strength.