Influence of Manufacturing Regimes on the Phase Transformation of Dental Zirconia

Markus Wertz; Hieronymus Hoelzig; Gert Kloess; Sebastian Hahnel; Andreas Koenig

doi:10.3390/ma14174980

Influence of Manufacturing Regimes on the Phase Transformation of Dental Zirconia

Materials (Basel). 2021 Aug 31;14(17):4980. doi: 10.3390/ma14174980.

Authors

Markus Wertz¹, Hieronymus Hoelzig², Gert Kloess², Sebastian Hahnel¹, Andreas Koenig¹

Affiliations

¹ Department of Prosthodontics and Material Sciences, Leipzig University, 04103 Leipzig, Germany.
² Institute of Mineralogy, Crystallography and Materials Science, Leipzig University, 04103 Leipzig, Germany.

Abstract

Background: The influence of typical manufacturing regimes for producing fixed dental prostheses (FDPs) from yttria partly-stabilized zirconia polycrystals (3Y/4Y/5Y-TZP) on the phase composition is quantified.

Methods: Fixed dental prostheses (FDPs) were designed using a CAD process and machined from different Y-TZP blanks from two manufacturers differing in yttria contents. Subsequent to sintering, the FDPs were glaze fired and air-blasted using alumina particles. Phase composition was determined with X-ray diffraction and quantified with Rietveld refinement.

Results: The blanks from VITA Zahnfabrik (VITA YZ HT, VITA YZ ST, VITA YZ XT) and Dental Direct (DD Bio ZX², DD cube ONE, DD cube X²) featured a rhombohedral portion with rather small crystallites and a small monoclinic portion for 3Y/4Y-TZPs, which increased after machining and disappeared after sintering. Glaze firing and air-blasting with alumina particles had no significant influence on the phase composition.

Conclusion: The phase history of dental zirconia is revealed, which may have implications on further processing and aging of the FDP (e.g. low temperature degradation) in mouth.

Keywords: Rietveld refinement; X-ray diffraction; computer-assisted manufacturing; fixed dental prosthesis; rhombohedral phase; yttria-stabilized zirconia.