The research project sample consisted of 30 blocks of composite resin , these blocks where divided into three equal groups , 10 of composite resin Z-250 from 3M ESPE Company , 10 of the composite resin Supreme from 3M ESPE Company ,10 of the composit
e resin Quixfil of Dentsply company, and has been testing the hardness Number, each sample individually. The aim of the previous procedures was to show the role of composite resin structure in determining the hardness number Through differences in the hardness number and the role of this hardness determining the mechanical properties for composite resin restorations cause of the importance of this property to understand the mechanical properties for a lot of restorative materials. And the result is that there is a statistically significant between the resin Quixfil and the Z-250 on the one hand and the Supreme resin on the other hand.
since teeth whitening is very important procedure in dental office. the effect
of peroxides on enamel tissue is of great interest in research. The aim of this in vitro study was to perform
a qualitative analysis of the human enamel microhardness af
ter the application of high concentration of
hydrogen peroxide (38%)with and without light activation, using Vickers microhardness tests.
This study aimed to investigate curing efficiency of a second generation - light
emitting diode(LED) curing unit to polymerise two kinds of resin ,one depends upon camphorquinone as a
single photo initiator while the other uses co-initiator besides camphorquinone .
The current research aims to study the effect of chemical disinfectants
on the roughness and hardness of the surface of the cobalt chrome
alloy, where the use of cleansing Sodium hypochlorite 5.25%
and distilled water (the control sample), Been ma
nufacturing 20
structure metal of the alloy cobalt chrome, each group containing 10
samples and was doused with samples intravenously cleared, then it
was measured surface roughness using an Atomic force microscope, and
measuring the hardness of the surface using a Vickers measuring device
hardness.
In this research the effect of Nickel addition by various
percentages on the mechanical properties of
Aluminum-Copper alloy was studied. After
adding Nickel the alloys was artificially aged for different
times, and the effect of Nickel on
the re
sponse of alloy to precipitation hardening was studied.
Where the effect of Nickel on the microscope structure was
studied, and on the mechanical properties as hardness, tensile
strength, yield strength and elongation. The results showed that
the increase of Nickel improve this properties, where the highest
values were obtained when the Nickel's percentage was 5% Wt.
