الفهرس 
Dental ceramics
organic phase (polymer). Manufacturers suggest a variety of indications for these ceramic-like materials in restorative dentistry.Only 14 pages are availabe for public view
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Abstract
Objectives: The purpose of this in vitro study is to evaluate the effect of simulated gastric
acidity on surface roughness of different types of dental ceramics.
Materials and methods: Fifty specimens were constructed and divided according to type of the
material into five groups (n=10), as follows:
group I: Partially stabilized zirconia (PSZ) (Prettaue).
group II: Fully stabilized zirconia (FSZ) (Prettaue anterior).
group III: lithium disilicate ceramics (Emax).
group IV: Zirconia-containing lithium silicate ceramics (ZLS) (Vita suprinity).
group V: Hybrid ceramics (Vita enamic).
All specimens were cut using a low-speed diamond saw (Isomet) into a rectangular shape with
the following dimension: 12mm width x 14mm length x 1 mm thickness. All the specimens were
glazed following the manufacturer recommendations. Each group was ultrasonically cleaned and
then evaluated for surface roughness using optical profilometer (spinning disk confocal
microscope with a white light source). All specimens were rinsed, disinfected then placed in a
simulated gastric acid solution of ph 1.2. Each specimen was immersed in 5 ml of the simulated
acid for 96 h in a37◦C incubator. Surface roughness of all tested groups was determined again
using optical profilometer. Statistical analysis: One-way ANOVA and post hock test (tukey-test)
was used to compare mean difference between groups. Paired t-test was used for comparing
(before and after) roughness in each group.
Results: There was significant difference (P=0.002) between all groups. It was found that there
is increase in surface roughness for all materials tested, but it was non-significant (P>0.05) for
prettaue (P=0.607), prettaue anterior (P=0.273) and vita suprinty group (P=0.201). There was
significant increase (P≤0. 05) for emax (P=0.007) and vita enamic groups (P=0.021). Prettaue
anterior group showed the least amount of surface roughness change (0.0006±0.002), while vita
enamic group showed the highest surface roughness change (0.0100±0.011).
Conclusions: The gastric acid significantly increased the surface roughness of hybrid ceramics
and lithium disilicate ceramics.