Optical properties, biaxial flexural strength, and reliability of new-generation lithium disilicate glass-ceramics after thermal cycling
Yükleniyor...
Tarih
2023
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Wiley
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Purpose: To investigate the color stability, translucency, biaxial flexural strength
(BFS), and reliability of nano-lithium disilicate and fully crystallized lithium disilicate
after thermal cycling and to compare with those of a commonly used lithium disilicate.
Materials and methods: Three lithium disilicate glass-ceramics were used to pre pare disk-shaped specimens (ø:12 mm, thickness: 1.2 mm) from A2 shaded HT blocks
(Amber Mill, AM; Initial LiSi Block, IN; IPS e.max CAD, EX). AM and EX specimens
were crystallized, and all specimens were polished with a polishing paste (Diamond
Polish Mint). A spectrophotometer (CM-26d) was used to measure color coordinates
before and after thermal cycling. BFS test was performed after thermal cycling. Color
differences (ΔE00) and relative translucency parameter (RTP) values were calculated.
One-way analysis of variance (ANOVA) (ΔE00 and BFS), two-way ANOVA followed
by Tukey’s HSD tests (RTP), and chi-square tests (Weibull modulus and characteristic
strength) were used for the statistical analyses (α = 0.05).
Results: No significant differences were observed among the ΔE00 values of tested
materials (df = 2, F = 2.933, p = 0.070). RTP values were only affected by material
type (p < 0.001) as AM had the highest RTP (p < 0.001), whereas IN and EX had sim ilar values (p ≥ 0.165). BFS values varied among tested materials (df = 2, F = 21.341,
p < 0.001). AM and EX had similar BFS values (p = 0.067) that were higher than that
of IN (p ≤ 0.001). Weibull moduli of the materials were similar (p = 0.305), whereas
EX had the highest and IN had the lowest characteristic strength values (p < 0.001)
Conclusions: Although nano-lithium disilicate had the highest translucency, all
materials had imperceptible color and translucency changes after thermal cycling
when reported threshold values were considered. Newly introduced lithium disilicate
glass–ceramics had adequate flexural strength as compared to the precursor material
