Comparison of sandblasted, ground and melt-etched zirconia crowns regarding adhesion strength to resin cement

Abstract

Objectives: The aim is to compare the adhesion between zirconia and cements attained with melt-etching with potassium hydrogen difluoride, KHF₂, with that found when such traditional surface treatments as sandblasting and ceramic stone grinding are employed.

Materials and methods: Groups of zirconia crowns where treated by sandblasting (n = 6), grinding with carbide bur (n = 6) or melt-etching with KHF₂ (n = 6) of the surface before cementation with a resin cement to an implant substitute made by Selective Laser Melting of a cobalt-chromium alloy. Tensile testing was performed to rupture, while measured increasing load at the zirconia-cement interface. The strength was calculated by dividing the rupture load with the contact area. The three groups were compared using one-way ANOVA.

Results: The adhesion strength between the zirconia crowns and the cement resulted in significant differences between all groups (p < .05). The sandblasted group had the lowest strength (5.2 ± 0.95 MPa), the ground group significantly higher (7.3 ± 1.49 MPa) and the melt-etched group the highest values (9.8 ± 1.37 MPa).

Conclusion: The adhesive strength of resin cement to zirconia can be ranked according to the surface preparation with surfaces melt-etched with KHF₂ stronger than ground which is stronger than sandblasted.

Keywords:

• Zirconia surface treatments
• tensile test
• adhesion strength

Acknowledgement

We would like to thank 3D-TEC Sweden AB for production of cobalt-chromium abutment substitutes and Zirkonzahn, Italy, for providing with zirconia material, and Ivoclar Vivadent Nordic (Sweden and Norway) for providing the cement. A special thanks to Erik Kleven at NIOM for his help in developing the tensile test equipment.

Disclosure statement

The authors declare that no conflicts of interest exist for any of the products or equipment mentioned in the paper.