Effect of low-temperature degradation on the fatigue performance of dental strength-gradient multilayered zirconia restorations

Copyright © 2024 Elsevier Ltd. All rights reserved..

OBJECTIVES: Fatigue and low-temperature degradation (LTD) are the main factors contributing to zirconia restoration failure. This study evaluated the effect of LTD on the fatigue performance of the novel "strength & shade-gradient" multilayered zirconia restorations.

METHODS: Discs (15 mm × 1.2 mm) of each yttria content layer from a newly developed strength-gradient multilayered zirconia were fabricated and under accelerated aging in an autoclave at 134℃ for 0 h, 32 h, and 64 h. Then, the phase transformation, microstructure, and mechanical properties after LTD were assessed. In addition, the crown samples, including the multi-Zir, 3Y-Zir, and 5Y-Zir were fabricated, and their monotonic and fatigue load before and after LTD, percentage of fatigue degradation (Sd) and the fracture morphology were investigated. Statistical analyses were performed using paired samples t-test (α' = α/3 = 0.017), one-way ANOVA and Weibull analysis.

RESULTS: After LTD, the phase transformation, surface roughness, depth of transformed zone, and residual stress were increased and inversely associated with the yttria content. The indentation elastic modulus and hardness after LTD decreased; however, there was no significant difference between the different yttria content layers. The monotonic and fatigue load of multi-Zir restorations decreased, but their Weibull modulus increased, and Sd decreased, similar to 3Y-Zir. The crack origin was associated with the cervical region.

CONCLUSION: These results show that although LTD reduces the absolute fatigue strength of strength-gradient multilayered zirconia restorations, it also reduces the effect of cyclic fatigue itself on the strength of zirconia (relative to monotonic strength), which might be due to the increase of residual stress.

CLINICAL SIGNIFICANCE: The novel "strength & shade-gradient" multilayered zirconia restorations show a promising performance during in vitro LTD and fatigue test and their reliability to some extent is comparable to 3Y-Zir. Yet, further in vivo longitudinal studies are warranted to confirm their precise performance.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:142

Enthalten in:

Journal of dentistry - 142(2024) vom: 28. März, Seite 104866

Sprache:

Englisch

Beteiligte Personen:

Li, Qiulan [VerfasserIn]
Yang, Yunxu [VerfasserIn]
Chen, Kuangyao [VerfasserIn]
Jiang, Yingyu [VerfasserIn]
Swain, Michael V [VerfasserIn]
Yao, Mianfeng [VerfasserIn]
He, Ying [VerfasserIn]
Liang, Yujie [VerfasserIn]
Jian, Yutao [VerfasserIn]
Zhao, Ke [VerfasserIn]

Links:

Volltext

Themen:

58784XQC3Y
C6V6S92N3C
Dental Materials
Fatigue strength
Journal Article
Low-temperature degradation
Restorations
S38N85C5G0
X8071685XT
Yttria
Yttria content
Yttrium
Zirconia
Zirconium
Zirconium oxide

Anmerkungen:

Date Completed 08.03.2024

Date Revised 08.03.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.jdent.2024.104866

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM367720280