Effect of sintering parameters on phase evolution and strength of dental lithium silicate glass-ceramics

被引：18

作者：

Lohbauer, Ulrich ^{[1
]}

Belli, Renan ^{[1
,2
]}

Alonso, Alexandre Abdalla ^{[2
]}

Goetz-Neunhoeffer, Friedlinde ^{[3
]}

Hurle, Katrin ^{[3
]}

机构：

[1] Friedrich Alexander Univ Erlangen Nurnberg FAU, Zahnklin Zahnerhaltung & Parodontol 1, Forschungslab Dent Biomat, Glueckstr 11, D-91054 Erlangen, Germany

[2] Sao Paulo State Univ Unesp, Inst Sci & Technol, Sao Jose Dos Campos, Brazil

[3] Friedrich Alexander Univ Erlangen Nurnberg FAU, GeoZentrum Nordbayern, Lehrstuhl Mineral, Schlossgarten 5a, D-91054 Erlangen, Germany

来源：

DENTAL MATERIALS | 2019年 / 35卷 / 10期

关键词：

Ceramics; Materials science; Restorative materials; Crystallization; X-ray Crystallography; 3 BALLS TEST; DISILICATE GLASS; CRYSTALLIZATION KINETICS; MECHANICAL-PROPERTIES; BRITTLE DISCS; MICROSTRUCTURE; FRACTURE; P2O5;

D O I：

10.1016/j.dental.2019.07.002

中图分类号：

R78 [口腔科学];

学科分类号：

1003 ;

摘要：

Objective. With the establishment of CAD/CAM technology, competing lithium silicate based formulations have been introduced for clinical use, but little is known about their phase composition. Here we investigate a commercially available SiO2-Al2O3-K2O-Li2O-P2O5-ZrO2 system to evaluate the crystal phase evolution during the second heat treatment by changing the main crystallization parameters. Methods. With a focus on the final stage of crystallization, we characterized the dimensional changes in the crystallographic structure of the residual Li2SiO3 and the lithium orthophosphate (Li3PO4) phases with variations in crystallization parameters, i.e. time, temperature and cooling rate over the range of the glass transition temperature T-g. The phase fractions (crystalline and glass) and the sizes of coherent scattering domains (CSDs) were resolved by means of quantitative X-Ray Diffraction using Rietveld refinement combined with an external standard method (G-factor). Biaxial flexure testing was conducted to evaluate the influence of crystallization parameters on the characteristic strength and natural defect distribution. Results. An increase in crystallization temperature from 840 to 880 degrees C resulted in a significant reduction of the Li2Si2O5 content, which indicated a reversion of the Li2SiO3 to Li2Si2O5 phase transformation. Reduction to 800 degrees C had no significant effect. Furthermore, the CSD sizes of Li2SiO3 and Li3PO4 continuously increased with increasing temperature, which was accompanied by an increase in strength parameters. Reducing the cooling rate over the range of T-g resulted in an increased strength at low failure probabilities. Significance. These findings help to establish recommendations for adjustment of the crystallization protocol, which has potential to increase the clinical reliability of the material investigated. (C) 2019 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

引用

页码：1360 / 1369

页数：10

共 34 条

[21] Phase characterization of lithium silicate biomedical glass-ceramics produced by two-stage crystallization [J].