Influence of Applied Pressure and Thickness Variation on the Bond Strength Between 3Y-TZP Zirconia and Self-Adhesive Resin Cement

This study evaluated the influence of applied pressure on the shear bond strength (SBS) between commercial 3Y-TZP zirconia and self-adhesive resin cement. Five test groups were created, each subjected to different applied pressures: 195.15, 97.47, 48.74, 9.75, and 0.20 kPa. A piston-type shear device was used to assess the effect of these pressures on cement layer thickness and SBS. The results demonstrated that the highest applied pressure (195.15 kPa) produced the thinnest cement layers (36.60 +/- 1.67 mu m) and the highest SBS values (58.8 +/- 1.6 MPa), whereas the lower applied pressure (0.20 kPa) resulted in the thickest cement layers (73.20 +/- 1.64 mu m) and significantly lower SBS (30.8 +/- 2.0 MPa). Regression analysis confirmed a strong correlation (R-2 = 0.82, p < 0.05) between cement thickness and SBS, indicating that cement thickness is a critical factor influencing adhesion. These findings highlight the importance of controlling applied pressure during cementation to optimize bonding performance. Standardizing pressure application through calibrated pressure devices may improve the durability of zirconia-based restorations and minimize variability during the cementation process.