Phase Formation, Mechanical Strength, and Bioactive Properties of Lithium Disilicate Glass-Ceramics with Different Al2O3 Contents

Arnon Kraipok; Teerapong Mamanee; Jetsada Ruangsuriya; Poomirat Nawarat; Wilaiwan Leenakul

doi:10.3390/ma15238283

Phase Formation, Mechanical Strength, and Bioactive Properties of Lithium Disilicate Glass-Ceramics with Different Al₂O₃ Contents

Materials (Basel). 2022 Nov 22;15(23):8283. doi: 10.3390/ma15238283.

Authors

Arnon Kraipok^{1

2}, Teerapong Mamanee³, Jetsada Ruangsuriya⁴, Poomirat Nawarat⁵, Wilaiwan Leenakul⁵

Affiliations

¹ Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
² Graduate School, Chiang Mai University, Chiang Mai 50200, Thailand.
³ Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200, Thailand.
⁴ Department of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand.
⁵ Division of Industrial Materials Science, Faculty of Science and Technology, Rajamangala University of Technology Phra Nakhon, Bangkok 10800, Thailand.

Abstract

Owing to its excellent mechanical properties and aesthetic tooth-like appearance, lithium disilicate glass-ceramic is more attractive as a crown for dental restorations. In this study, lithium disilicate glass-ceramics were prepared from SiO₂-Li₂O-K₂O-P₂O₅-CeO₂ glass systems with various Al₂O₃ contents. The mixed glass was then heat-treated at 600 °C and 800 °C for 2 h to form glass-ceramic samples. Phase formation, microstructure, mechanical properties and bioactivity were investigated. The phase formation analysis confirmed the presence of Li₂Si₂O₅ in all the samples. The glass-ceramic sample with an Al₂O₃ content of 1 wt% showed rod-like Li₂Si₂O₅ crystals that could contribute to the delay in crack propagation and demonstrated the highest mechanical properties. Surface treatment with hydrofluoric acid followed by a silane-coupling agent provided the highest micro-shear bond strength for all ceramic conditions, with no significant difference between ceramic samples. The biocompatibility tests of the material showed that Al₂O₃-added lithium disilicate glass-ceramic sample was bioactive, thus activating protein production and stimulating the alkaline phosphatase (ALP) activity of osteoblast-like cells.

Keywords: Al2O3; crack propagation; crystals; glass-ceramic; heat treatment; lithium disilicate.

Grants and funding

This research was funded by the National Research University Project under Thailand’s Office of the Higher Education Commission grant number 2832294.