The research aims to evaluate the micro shear bond strength of the calcium silicate cement
(Biodentine) and the glass ionomer cement (GIC) to dentine. The study was performed using
upper or lower premolars, and samples were divided into six equal s
ubgroups according to
the time period (3 h, 1 day, 1 week, 2 weeks, 4 weeks, 8 weeks), in order to study changes in
the values of shear bond strength with time. The comparative study showed that the success
rate of adhesion in the Biodentine group was smaller than that in the GIC group for the tested
premolars after 3 hours and one day, whereas the success rate in the Biodentine group was
greater than that in the GIC group for the tested premolars after 8 weeks.
Results showed a positive correlation between the mean values of shear bond strengths and
the studied time in Biodentine group, which ranged from 1.49 ± 0.18 MPa at 3 hours to a
maximum value of 2.65 ± 0.26 MPa after 8 weeks. While there was a negative correlation
between the mean values and the studied time in the GIC group and values ranged from 3.02
± 0.13 MPa at 3 hours and 2.06 ± 0.09 MPa at 8 weeks.
The study showed the advantage of Biodentine compared with GIC in terms of
micro-bonding to dentine, which can have a clinically significant importance in preventing
the micro leakage and reducing bacterial contamination.
The aim of this study is improving the durability of precast products of Glass Fiber
Reinforced Concrete (GRC) and in the context of sustainability applications, reduction of
cement consumption and replacement of it with green materials. This study
has been done
to test the role of the natural pozzolan from Shihan Hill in As Suwayda as supplementary
cementing material by 10% -15% -20% - 25%, and to determine the effect of it on the
consistency and flexure strength over 180 days, as well as to test its role in improving the
micro-structure of the mixture by reducing the content of Ca(OH)2 and increasing C-S-H
& C-A-S-H gel, which were tested using X-Ray Diffraction (XRD) and Energy Dispersive
X-Ray (EDX) techniques, and as a result reduced the erosion of fibers as shown in images
by Scanning Electronic Electron Microscopy (SEM). Moreover the role of pozzolana has
been studied in controlling the degradation of the material over time which tested by
immersion in hot water 50° for 150 days and by drying – wetting cycles. Also the effect of
pozzolana on absorption, porosity and resistance of sulfates attacks was studied. The
results have shown that the used natural pozzolana has no negative effect on consistency or
mechanical properties, and it improved all the studied durability factors.
The purpose of this in vitro study to evaluate the effect
of ceramic primer on the bond strength of adhesive resin cement to
zirconia ceramic surface.
studying the recycling of bituminous pavements
is important to achieve a set of objectives. The most
important one is to examine the asphalt obtained from the
recycled bituminous pavements in order to identify its
properties and suitability for reuse according to its
serviceability, reductions and cost benefit.
An appropriate bond between glass‑ionomer and the superficial
resin materials is very important for the success of sandwich
technique. The aim of the present in vitro study was to evaluate the
effect of three surface treatments of conventional glass‑ionomer on
its shear bond strength to giomer
This research was aimed to assess the pollution from Tartous Cement Factory of
some heavy metal by using of the bark of olive trees and Lichens as Bio-indicators. The
olive trees was chosen as that predominant vegetation type in the study area. Bar
k samples
of olive trees and the lichens were collected from several villages surrounding the Cement
Factory at different distances (1-2-3-4-5-6-7) km from the center of the Cement Factory in
the eastern and north-eastern region of the Cement plant (where the prevailing winds in the
region is western and southern Western).
The results showed that the concentration of heavy elements in the bark of olive trees
and lichens (ppm) take the same trend even thought there are differences in concentration
between them by the overall average for all sites was as follows: iron > manganese >
copper > lead. We note the high concentration of iron in bark of olive trees compared to
lichens, but the rest of the elements it was statistically identical. The results also showed a
significant correlation between the concentrations of manganese element in each of the
bark and Lichens, and the existence of a negative correlation between the concentration of
manganese and distance for both Lichens and bark. Concerning the altitude above sea level
the results showed existence of significant and negative correlation with all of Iron,
Manganese and Lead in Lichens.
Five mixtures of ordinary concrete of dolomite aggregates were
prepared by changing the water to cement ratio. Thirty six cubic
concrete samples were prepared for every mixture.
Dental caries is an infectious bacterial disease that results in
localized dissolution and destruction of thecalcified tissues of the
teeth. There are many dental materials which have antibacterial
effects.
The aim of this study is to evaluate th
e antibacterial effects of the
commercial types of Glass Ionomers Cement (GIC)Kaviton® CEM
and Composite Prime Dental® using at the Faculty of Dentistry in
Al- Hawash Private University (HPU), and to make comparsion
between these.
According to the Syrian standard 3411 & European standard EN 197-1, Portland
pozzolana cements and Portland limestone cements can be produced by partial replacement
of pozzolan or limestone up to 35%. Despite of the economical, ecological and techn
ical
benefits of adding natural pozzolan and limestone powder, they are often associated with
shortcomings.
The objective of the study is to investigate the effect of adding natural pozzolan,
limestone powder or both on the mechanical strength development of the prepared cement
mortars. In the study, sixteen types of binders (one OPC, six binary and nine ternary
blended cements) with different replacement levels of natural pozzolan, limestone powder
or both have been produced. The development of the compressive and flexural tensile
strength of all mortar specimens has been investigated after 2,7,28 & 90 days curing,
respectively.
Test results revealed that there was a decrease in strength with increasing amounts of
natural pozzolan. In addition, there was found an increase in the early age strength with
adding limestone powder. The increase in compressive strength when adding both natural
pozzolan and limestone powder has also been noted. Further, based on the results obtained,
an empirical equation was derived to predict the mechanical strengths of binary & ternary
blended cement mortars with curing times. The influence of adding natural pozzolan,
limestone powder or both on some physical properties of binary and ternary blended
cements have been reported, as well.
Objective: To compare effect laser Er:Yag and polyacrylic acid on
microleakage of of resin-modified glass-ionomer cement.
Analysis of variance shows no statistical differences between
three groups .
