Color stability of lithium disilicate ceramics after aging and immersion in common beverages
Abstract
Statement of problem
The
color of an esthetic restoration and its color stability are important
for long-term success. However, the impact of common beverages on
lithium disilicate ceramic is not well known.
Purpose
The
purpose of this in vitro study was to investigate color variations of
lithium disilicate ceramics after thermal cycling (TC) and immersion in
commonly consumed beverages.
Material and methods
A
total of 288 specimens (1×10×10 mm) were fabricated from IPS e-max
computer-aided design (CAD) (n=72), IPS e-max CERAM ([CER] n=72), IPS
e-max Press with glazing ([PG] n=72), and IPS e-max Press without
glazing ([PNG] n=72) according to the manufacturer's instructions. Each
group was divided into 4 subgroups (n=18): TC, coffee, black tea, and
red wine. Thermal cycling was performed at 21 900 cycles at 5°C, 37°C,
55°C, and 37°C (3 years’ clinical simulation), whereas the specimens
were soaked in the staining solutions for up to 54 hours (3 years’
clinical simulation). Color parameters L*, a*, and b* were assessed with
an ultraviolet-visible spectroscopy recording spectrophotometer. Color
difference (ΔE) was calculated using the equation [ΔΕ= [(ΔL*)2 + (Δa*)2 + (Δb*)2]½].
Intraexaminer reliability was assessed by using the intraclass
correlation coefficient. Two-way analysis of variance was used for the
analysis of ΔΕ, and the parameters L*, a*, and b* were analyzed with
linear mixed models for repeated measurements and the Bonferroni
pair-wise comparison test (α=.05).
Results
Parameters ΔΕ, L*, a*, and b* were significantly affected by the interaction between material and treatment (P<.001).
A ΔΕ >1 was recorded for PG with tea, wine, and coffee, PG after TC
and CER after TC. For L*, greater reduction was observed for PNG with
tea and CER after TC, whereas for a* significant changes were positive
(to red shades), except for PNG with TC, where PNG with wine showed the
greatest positive change. For b*, significant changes were negative (to
blue shades) except for PNG with tea and coffee and CAD with tea.
Conclusions
All
groups demonstrated color changes below the clinically perceptible
level (ΔΕ<3 .7="" color="" differences="" except="" in="" png="" showed="" significant="" statistically="" tea="" which="">4). CAD presented higher color
stability compared with the nonglazed Press specimens.
Comments