Effects of multiple firings on mechanical properties and resin bonding of lithium disilicate glass-ceramic

Hongliang Meng; Haifeng Xie; Lu Yang; Bingzhuo Chen; Ying Chen; Huaiqin Zhang; Chen Chen

doi:10.1016/j.jmbbm.2018.08.015

Effects of multiple firings on mechanical properties and resin bonding of lithium disilicate glass-ceramic

J Mech Behav Biomed Mater. 2018 Dec:88:362-369. doi: 10.1016/j.jmbbm.2018.08.015. Epub 2018 Aug 21.

Authors

Hongliang Meng¹, Haifeng Xie¹, Lu Yang¹, Bingzhuo Chen¹, Ying Chen¹, Huaiqin Zhang¹, Chen Chen²

Affiliations

¹ Jiangsu Key Laboratory of Oral Diseases; Department of Prosthodontics, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China.
² Jiangsu Key Laboratory of Oral Diseases; Department of Endodontics, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China. Electronic address: ccchicy@njmu.edu.cn.

PMID: 30199839
DOI: 10.1016/j.jmbbm.2018.08.015

Abstract

Objectives: This study aimed to evaluate the effects of different firing cycles on surface hardness, fracture toughness, and roughness of lithium disilicate glass-ceramic, as well as their bond strength to resin.

Materials and methods: A total of 320 polished lithium disilicate glass-ceramic plates were assigned to four main groups (n = 60) to receive one, two, three, or four firing cycles, respectively. Ceramic plates of the four groups were conditioned with HF acid followed by silanization. The pre-treated ceramic plates were cemented with composite resin cylinders using conventional or self-adhesive resin cements to build bonded specimens, and submitted to shear-bond-strength (SBS) testing after water storage for 24 h or 3 mo at 37 °C. The ceramic received different firing cycles after polishing or HF etching was observed using a scanning electron microscope, and their surface roughnesses were determined by a profilometer. The surface Vickers hardness, fracture toughness, and related Weibull analysis results of the polished ceramics after undergoing different firing-cycle times were compared.

Results: One sintering significantly increased fracture toughness of lithium disilicate glass-ceramic; however, multiple firing cycles failed to increase it further. Weibull analysis revealed a significant difference in terms of structural reliability among the specimens receiving 0-4 firing cycles. Specimens that received no firing cycle showed the highest surface hardness. Multiple firing cycles had no significant influence on the surface Vickers hardness and surface roughness. HF etching increased surface roughness, and the roughened surface improved the resin SBS of lithium disilicate glass-ceramic. Multiple firing cycles had no significant effect on surface roughness. Furthermore, multiple firing cycles and 3-mo water storage had no significant effect on the SBS.

Conclusions: The mechanical properties of lithium disilicate glass-ceramics would be partially affected by multiple firing cycles, while their resin bonding would not be.

Keywords: Lithium disilicate glass-ceramic; Multiple firings; Shear bond strength; Surface hardness; Surface roughness; Weibull analysis.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Ceramics / chemistry*
Dental Porcelain / chemistry*
Glass / chemistry*
Materials Testing
Mechanical Phenomena*
Resins, Synthetic / chemistry*
Surface Properties
Temperature

Substances

Resins, Synthetic
lithia disilicate
Dental Porcelain