Two-body wear of monolithic, veneered and glazed zirconia and their corresponding enamel antagonists

Abstract

Objective. This study tested whether the two-body wear of monolithic zirconia and their corresponding enamel antagonists was higher compared to monolithic alloy and veneered zirconia. Materials and methods. Cylindrical specimens (N = 36, n = 6) were prepared out of (A) veneered zirconia (VZ), (B) glazed zirconia using a glaze ceramic (GZC), (C) glazed zirconia using a glaze spray (GZS), (D) manually polished monolithic zirconia (MAZ), (E) mechanically polished monolithic zirconia (MEZ) and (F) monolithic base alloy (control group, MA). Wear tests were performed in a chewing simulator (49 N, 1.7 Hz, 5°C/50°C) with enamel antagonists. The wear analysis was performed using a 3D profilometer before and after 120,000, 240,000, 640,000 and 1,200,000 masticatory cycles. SEM images were used for evaluating wear qualitatively. The longitudinal results were analysed using linear mixed models (α = 0.05). Results. Materials (p < 0.001) and number of masticatory cycles (p < 0.001) had a significant effect on the wear level. The least enamel antagonist wear was observed for MAZ and MEZ (27.3 ± 15.2, 28 ± 11.1 μm, respectively). GZC (118 ± 30.9 μm) showed the highest wear of enamel antagonists. The highest wear rate in the material was observed in GZS (91.3 ± 38.6 μm). While in the groups of MA, VZ, GZC and GZS 50% of the specimens developed cracks in enamel, it was 100% in MAZ and MEZ groups. Conclusion. Polished monolithic zirconia showed lower wear rate on enamel antagonists as well as within the material itself but developed higher rates of enamel cracks.

Key Words::

• monolithic zirconia
• ceramic
• abrasion
• enamel
• two-body wear

Acknowledgements

The authors are grateful to Mrs Jacqueline Hofmann, Center of Dental Medicine, University of Zurich, for performing the scanning electron microscopy. Special thanks go to Wieland Dental + Technik, Pforzheim, Germany for support this study.

Declaration of interest: The authors report no conflicts of interest.