الفهرس 
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Abstract
Recurrent caries and marginal leakage are common problems annoy
many dental patients, also esthetics is the main demand. So several bioactive
restorative materials have been used to inhibit tooth demineralization, help to
regain tooth structure by creating an optimal pH, bacterial inhibition, good
seal with tooth structure, and active mineral ions release.
The present in-vitro research studied the effect of bioactive restorative
materials on the shear bond strength to dentin surface. 60 freshly extracted
molars were utilized. The roots of each tooth were embedded in auto
polymerizing resin 1mm below cemento enamel junction inside a splitted
metallic holder which have a fitting surface covered with a separating
medium. The experimental occlusal surfaces had to be free of contamination
by acrylic resin and were carefully trimmed using a diamond disc adapted to
low speed hand piece under copious water coolant to expose clean flat
occlusal dentin surfaces, 600 Grit Wet Silicon Carbide abrasive papers were
used to finish the dentin surface in a circular motion and to create a
standardized smear layer.
The prepared specimens were randomly divided into three groups (20
each) according to type of bioactive material used with its recommended
dentin treatment as follows:
group I: application of 25% polyacrylic acid on dentin surface
followed by application of Fuji IX GP EXTRA glass ionomer, which had
dimensions (4mm in diameter × 3mm in thickness).
group II: FL primer was applied on the exposed dentin surface, air
dried , an even layer of FL bond II was applied, light-cured ,followed by
application of beautifill II Giomer. group III: dentin surface of each specimen was etched with 38%
phosphoric acid gel followed by application of ACTIVA TM BIOACTIVE
restorative material.
All specimens stored in distilled water at 37 °C and at100% humidity.
All materials were applied according to the manufacturer’s instructions.
All groups were subdivided into two equal subgroups (A&B). Half of
specimens (subgroup B) were thermocycled in thermocycling apparatus for
500 cycles from 5°C to 55°C with 30 sec. dwell time, 20 seconds transfer
time.
shear bond strength testing using an Instron machine. A shear force
was applied to each specimen at a crosshead speed of 0.5mm/min until
fracture. The force of debonding was then divided by the cross sectional
bonding area to obtain the shear bond strength.
The results of this study revealed that, gp III (ACTIVA) recorded the
highest shear bond strength values (6.587±0.979), followed by gp II
(Beautifill II) (6.029±0.820) while the lowest shear bond strength values
were found at gp I (FUJI IX GP EXTRA) with mean values of( 3.514
±0.571).
ANOVA test was used to compare the tested groups at each subgroup
at a level of significance 0.05. A statistical significant difference was
recorded. Therefore statistical analysis using (Tukey`s test) was performed to
find out which group is responsible for the recorded difference. It was found
that group I was responsible since a significant difference was present.
The dentin sides of all fractured interfaces were examined under a
stereomicroscope at magnification 40X to determine the mode of failure.