Optimized sintering and mechanical properties of Y-TZP ceramics for dental restorations by adding lithium disilicate glass ceramics

Ke Li,Congqin Ning,Jiancun Rao

doi:10.1007/s40145-021-0507-9

Abstract

The novel dental ceramics can be fabricated at lower temperatures when sol-gel derived lithium disilicate glass ceramics (LDGC) was used as an additive for yttria stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramics. The effect of LDGC on the sintering, mechanical, and translucent properties of Y-TZP ceramics was investigated in the present study. The results showed that the LDGC additive effectively improved the densification of Y-TZP at 1100 °C, which was much lower than the sintering temperature for pure Y-TZP. When sintered at 1100 °C, the Y-TZP with 1 wt% LDGC reached a relative density of 95.45%, and prossessed a flexural strength of 482.4 MPa and a fracture toughness of 5.94 MPa·m1/2. Moreover, its translucency was also improved. While, the addition of LDGC could result in an escape of yttrium atoms from the grain lattice of zirconia, which induced the tetragonal-monoclinic transformation of zirconia and abnormal growth of monoclinic grains. The escaped yttrium atoms diffused into the intergranular glass phase. The results indicated that the novel Y-TZP-LDGC ceramics has a great potential to be used for all-ceramic restorations.

Highlights

In recent years, all-ceramic restorations have attracted an increasing attention due to their unique characteristics of combining good mechanical properties, excellentJ Adv Ceram 2021, 10(5): 0–0(9–10 MPa·m1/2) [6,7,8,9]
The DSC profile shows that the melting point of lithium disilicate glass ceramics (LDGC) is 980 °C, which means that LDGC powder will be melted into liquid phase when the sintering temperature is higher than 980 °C
The present work investigates the influence of LDGC addition on the sintering, mechanical, and translucent properties of yttria stabilized tetragonal zirconia polycrystalline (Y–TZP) ceramics

Summary

Introduction

All-ceramic restorations have attracted an increasing attention due to their unique characteristics of combining good mechanical properties, excellentJ Adv Ceram 2021, 10(5): 0–0(9–10 MPa·m1/2) [6,7,8,9]. Zirconia plays an important role in all-ceramic restoration system. It is well-known that zirconia has much higher fracture toughness than other ceramics used in dentistry, owing to the effect of transformation-toughening phenomena associated with the martensitic transformation, i.e., tetragonal to monoclinic phase (t–m) [6,10]. Several researches have reported about the performance of additives on the sintering properties of Y–TZP. Those results showed that the densification of Y–TZP could be effectively promoted due to the viscous flow of glass phase during sintering, such as CaO–Al2O3–SiO2 (CAS) and Li2O– Al2O3–SiO2 (LAS) [13,16,17,18,19,20]

Methods

Results

Conclusion