Evaluation and comparison of the characteristics of three pressable lithium disilicate glass ceramic materials

Objective: The objective of this study was to evaluate the biaxial flexural strength, wear resistance, and acid resistance of three different lithium disilicate glass ceramic materials. Methods: Three lithium disilicate glass ceramic materials were used in this study: GC Initial LiSi Press (LiSi; GC), IPS e.max Press (e.max; Ivoclar Vivadent), and Vintage LD Press (LD; Shofu). Biaxial flexural strength and chemical solubility tests were conducted according to ISO 6872:2015. The biaxial flexural strength test was conducted using a universal testing machine. The wear test was performed as a two-body wear test, followed by analysis via measurement of the maximum wear depth (µm) with a laser microscope. The chemical solubility test with acid was followed by analysis via measurement of the mass loss (µg/cm2). Finally, the results were analyzed via one-way ANOVA (α = 0.05) and Bonferroni’s multiple comparison tests. Results: The pre- and post-thermal-stress flexural strengths of all the ceramic material groups did not differ significantly. The flexural strengths of LiSi and e.max were significantly higher than that of LD. In the two-body wear test, LiSi showed the lowest wear depth (significantly lower than that of the other ceramic material groups). The wear depth of e.max was significantly lower (resp. higher) than that of LD (resp. LiSi). The chemical solubility of LiSi was the lowest, and the dissolution amount of LD was not significantly different from that ofe.max. Significance: LiSi has better mechanical properties and chemical stability than other lithium disilicate glass ceramic materials.