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.
The ideal goal of periodontal instrumentation is to effectively remove plaque
and calculus without causing root surface damage and various instruments have been designed to achieve
this goal. Root planing aim to create a root surface which is biolo
gically acceptable to surrounding soft
tissues and increase root surface roughness.
Aim of study: To evaluate the increasing of root surface roughness produced by hand curettes and
piezoelectric ultrasonic instrument with different power settings .
The aim of the study is to evaluate the surface roughness of the resin Tetric N Ceram (Ivoclarvivadent ) after different finishing and polishing techniques. 50 specimens of (10×2) mm were made and distributed in 5 groups (N=10), According to the tech
nique employed: First group G1: Tengustinecarbid burs, Second group G2: Astopol system, Third group G3: Stem discs, Fourth group G4: Tengustinecarbid burs then Astropol system, Fifth group G5: Tengustinecarbid burs then Stem discs. A coarse roughness diamond bur was applied , then applied a super fine diamond bur on all specimens of the study before starting any procedure of finishing and polishing. After finishing and polishing techniques, surface roughness )Ra μm( was measured using InfiniteFocus– Alicona. Data were subjected to Kruskal-Wallis and Mann-Whitney U test at 5% significance level.
In this research, It has been studied the effect of compaction pressure on
the final roughness for the top and down surfaces for the green compacts
that manufactured by meal powder technique and it has been studied also
the effect of piston veloci
ty (compaction velocity) on the final roughness
for the same two surfaces.
The results present that the curved for the top surface roughness is
completely decreasing and as the pressure has increased, the value for
roughness has reduced and the mean roughness (Ra) has very close
values, where these values have made curve from second degree and
opposite relationship. The results were same for the down surfaces but
with different variations.
This paper reports the results of an experimental investigation
carried out to study the effects of machining parameters such as
pulsed current on material removal rate, diameteral overcut,
electrode wear and surface roughness in electric discharg
e
machining of En-31 tool steel (IS designation: T105 Cr 1 Mn 60)
hardened and tempered to 55HRc. The work material was ED
machined with copper, copper tungsten, brass and aluminum
electrodes by varying the pulsed current at reverse polarity.
The aim of this study is to determine strength of adhesive single-lap joints of
Aluminum alloys which are widely used in geometric applications. It was investigated to
define the influence of overlap length and surface roughness value on shear stre
ngth of
achieved adhesive joints. It was used Epoxy and Acrylic adhesives to prepare adhesive
joints and all the specimens were subjected to axial tensile tests and the results are
presented as a comparison.
Results of those tests showed that shear strength increased with increasing each of
overlap length and surface roughness of adherends and Acrelicadhesiveproduced4better
results according to failure mode of tested samples.
