Flexural Strength of Zirconia-Reinforced Lithium Silicate Ceramic (ZLS) Before and After Thermomechanical Aging.
Alfirdous, Rayyan.
2019
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Introduction: Dental restorations' success rate is controlled
largely by their marginal adaptation, fracture resistance, and aesthetic value.
Recently, novel ceramic materials have been developed in an effort to combine
polycrystalline ceramics' mechanical properties and glass matrix ceramics'
superior aesthetics. The zirconia-reinforced lithium silicate ceramic, ZLS
(Celtra® Duo), is a ... read morepromising restorative material that, according to the
manufacturer, exhibits a unique behavior when subjected to aging. Study
objectives: The goals of this in-vitro study were: to evaluate aging's effect on
the flexural strength of the zirconia reinforced lithium silicate glass-ceramics
introduced recently, and compare aging's effect on zirconia reinforced lithium
silicate glass-ceramic and lithium disilicate ceramics' flexural strength.
Materials & Methods: Lithium disilicate ceramics (IPS e-max CAD, Ivoclar
Vivadent, Liechtenstein) and zirconia-reinforced lithium silicate (Celtra® Duo LT
A1, C14, Dentsply, Germany) were used in this study. A total of 30 plates 14.5 ×
12.5 mm in size and 1.5 mm thick were made of each material and were polished,
glazed, and assigned randomly to two groups (A) Aging/cyclic loading, and (B) No
Aging. The specimens from group A underwent 10,000 cycles in water baths that
ranged from 6.5-60 0C, and then subjected to 250,000 cycles of mechanical loading
with a force of 50N. The three-point flexural strength test was applied and the
stress at the point of failure was used, for all specimens in group A and B, to
calculate flexural strength in MPa. Two-way analysis of variance (ANOVA) was
conducted with the significance level set at 0.05. SPSS v. 24. Results: The mean ±
SD flexural strength for the non-aged lithium disilicate group was 425.47 ± 79.98
MPa, while it was 405.48 ± 86.39 MPa for the group that was exposed to
thermomechanical aging. The mean ± SD flexural strength of the ZLS non-aged group
was 319.79 ± 78.75 MPa, and that of the group that received thermomechanical aging
was 326.68 ± 51.48 MPa. The ANOVA indicated that the difference in lithium
disilicate ceramic and ZLS's flexural strength was significant (p < 0.001), in
which lithium disilicate ceramic had higher flexural strength values. However,
there was no statistically significant difference in flexural strength between the
ceramics that were aged and those that were not (p = 0.738). Conclusions: Within
the limitations of this study, it can be concluded that lithium disilicate has a
higher flexural strength than ZLS before and after thermomechanical aging. However
for the materials itself, there was no significant difference between the aged and
non-aged samples.
Thesis (M.S.)--Tufts University, 2019.
Submitted to the Dept. of Posthodontics.
Advisors: Ala Ali, and Aikaterini Kostagianni.
Committee: Matthew Finkelman, and Aikaterini Papathanasiou.
Keyword: Dentistry.read less - ID:
- 2z10x362c
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