الفهرس 
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Abstract
Caçarison and evaluation of 4 recently used types of investment
teria1s were done in canparison to conventional type.
These materials were:
1- N Duroterrn 3
2- Neo Durotenu 5
3- Neo Duroterrn 7
4- Neo Duroterm L
5- Durotenn
The following tests were performed:
a) Measuring the setting expansion: in relation to time for t hours by the Contour Projector 6(X).
b) Measuring the thermal expansion: in relation to temperature, gradually fran roan temperature to 700°C by the Precision Dial
Gange.
c) asuring the cooling contraction: in relation to decreasing temperature fran 700°C to the roan temperature by the Precision
Dial Gauge.
d) Evaluating the total expansion of the casting investment materials studied by casting gold inlays
Results were the following:
j Setting Expansion
It was found that prolonged setting time up to one hour gave satisfactory setting expansion.