الفهرس 
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Abstract
This study evaluated the accuracy of sulcus depth reproduction of
hydrophilic condensation silicone impression material and compared it with the
old hydrophobic condensation silicone using addition silicone as a gold standard
(control), under two experimental conditions (wet and dry), and to design a more
standardized testing model, simulating to some extent the gingival sulcus and the
critical area of the finish line, which represents a critical detail, had to be
reproduced accurately in most of fixed prosthesis to be constructed.
The gingival sulcus simulation model was made of stainless steel, it
consists of two parts; tooth form die, machined to form a truncated cone,
representing a prepared crown with 1mm shoulder finish line and cylindrical
die housing machined with a central hole designed to fit the tooth form die, and
produced by 200<m at the upper 2mm of the central hole to create a sulcus
surround the truncated cone circumferentially when the tooth form die in place.
Putty and wash technique was used for impression making of the
truncated cone with a circumferential 2mm deep sulcus, 200 μm wide.
A total of 60 Impression specimens were made, 20 impressions for
each impression material.
Impressions were made in two experimental conditions, wet and dry,
10 impression specimens for each condition by each of the impression
materials under investigation.
For wet condition the sulcus and the shoulder finish line was filled with
distilled water and the syringe impression was directly applied to wet surface
without any drying.
The depth of gingival sulcus reproduction was then evaluated by
measurement of the length of the impression rim, which penetrates the
simulated gingival sulcus. The measurements were done by stereomicroscope
equipped with image processing software, capable of measuring to 0.001mm.
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All calculations were performed and value recorded. Statistical analysis
was done to evaluate and identify any significant differences between
impression materials in the depth of sulcus reproduction recorded by each
impression material at each moisture condition.
Results had shown that; significant difference was found between the
different impression materials in depth of sulcus reproduction in the two
experimental moisture conditions.
Addition silicone was the most accurate in the depth reproduction of
the gingival sulcus in the two moisture conditions accurately. Hydrophilic
condensation silicone was comparable to additional silicone with no
significant difference.
Both addition silicone and hydrophilic condensation silicone were
significantly better than hydrophobic condensation silicone impression
material in sulcus depth reproduction in the wet conditions and in the quality.