1. Two-step sintering suppresses grain growth and improves flexural strength of dental zirconia.
- Author
-
Lim CH, Alves LMM, Vardhaman S, Bonfante EA, Kim DK, and Zhang Y
- Abstract
Objectives: This study aimed to elucidate the effect of various two-step sintering (TSS) protocols on the physical, mechanical, and optical properties of partially stabilized zirconia with different yttria dopant concentrations (Y-PSZ)., Methods: Disc-shaped specimens were obtained from most widely used commercial dental zirconia powders of various Y contents (Tosoh Corp.) by uniaxial pressing followed by cold-isostatic pressing. Densification was carried out using TSS protocols with varying temperatures for both sintering steps. Relative density (ρ
Rel ), microstructure, and phase content were analyzed. Biaxial flexural strength (σ) and translucency parameter (TP) were evaluated., Results: The TSS results were compared with optimized conventional sintering (CS) results from a previous study for the same Y-PSZ compositions. TSS 3Y-PSZ and 4Y-PSZ reached similar ρRel to those of their CS counterparts, whereas 5Y-PSZ failed to achieve that regardless of TSS protocol. TSS yielded less cubic phase compared to CS, especially for 3Y-PSZ and for higher temperatures. TSS suppressed the grain growth throughout the temperature range investigated, promoting smaller grains than CS (p < 0.05). The TP values for TSS Y-PSZ were lower than those of CS (p ≤ 0.0001), except for 3Y-PSZ. The σ values for TSS Y-PSZ were significantly higher than those of CS (p ≤ 0.0002)., Significance: TSS increased strength without significantly jeopardizing the optical properties of various Y-PSZ compositions relative to their CS counterparts. This alternative sintering method appears to be a promising technique for controlling grain growth while eliminating porosities in dental Y-PSZ ceramics, thus potentially enhancing the clinical longevity of zirconia restorations., Competing Interests: Declaration of Competing Interest All authors declare that they have no conflicts of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)- Published
- 2024
- Full Text
- View/download PDF