الفهرس 
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Abstract
Over the past years, esthetic dentistry has shown considerable progress, leading to the development of a
number of improved restorative materials. Currently the
main concerns regarding the performance of these
materials refer to their durability, marginal seal and
strength. This study was designed to assess and compare microleakage and shear bond strength of primary and
permanent teeth of 80 teeth and to evaluate flextural
strength prior to and after thermocycling of 80 specimens.
Teeth were cleaned debrided of soft tissue remnants,
cleaned with ultrasonic scaler and stored in saline at 4
degrees within one month after extraction until use. The
main groups were classified as follows:
a) Group A: Forty permanent teeth.
b) Group B: Forty primary teeth.
Each group was divided into 2 subgroups containing 20 teeth for each restorative material, 10 teeth were used for assessing microleakage and other 10 teeth for assessing
shear bond strength.
97 Summary
Microleakage:
Cavity class V was prepared with dimensions 3 mm
mesio-distal width and 2 mm occluso-gingival length. The
depth was adjusted to be 2 mm with the aid of periodontal
probe. The cavities were restored with either Chemfil Rock
or Ketac Fil glass ionomer. In each material the
manufacturer’s instructions were strictly followed,
thermocycling was done for all teeth then microleakage
testing procedures were done.
Shear bond strength:
The materials were manipulated according to the
manufacturer’s instructions and were placed on smoothened
buccal or lingual surface by using a mold measuring 3 mm
diameter and 2 mm depth to form glass ionomer discs. All the
samples were stored in distilled water and then subjected to
thermocycling then shear bond strength was tested by using
Universal Testing Machine.
Flextural strength:
80 specimens (40 non thermocycled and 40 thermocycled) were made by inserting the material into a metal mold (25 × 2 × 2 mm) according to manufacturer’s instructions. Three-point98
Summary
bending test was carried out for all the 80 specimens by a
universal testing machine then flextural strength was calculated.
Data was tabulated and statistically analyzed. The results
showed that Chemfil Rock with permanent teeth recorded the
highest leakage sore mean value followed by Chemfil Rock with
primary teeth then ketac Fil with primary teeth while ketac Fil
with permanent teeth recorded the lowest leakage sore mean
value.
The results also showed ketac Fil with permanent recorded
the highest bond strength mean value followed by ketac Fil with
primary then Chemfil Rock with primary teeth while Chemfil
Rock with permanent teeth recorded the lowest bond strength
mean value.
The results also showed that Ketac Fil with non
thermocycled 1 month subgroup recorded the highest flextural
strength mean value followed by thermocycled 1 month subgroup
then non thermocycled 24 hours subgroup while thermocycled 24
hours subgroup recorded the lowest bond strength mean value.
The difference in flextural strength means between all Chemfil
Rock subgroups were statistically non significant.