الفهرس 
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Abstract
A total of 35 extracted human premolars were used in this study.
After extraction, the teeth were thoroughly cleaned from blood and any
soft tissue, and stored in distilled water. Each tooth was sectioned mesiodistally
into two halves down to the root after which halves were
embedded in auto-cure acrylic resin blocks, maintaining a record of
complementary halves.
Teeth were divided into 5 main groups according to the dentin
conditioner regimen; ranging from none, to that of NaOCl, or EDTA, or
EDTA followed by NaOCl, or NaOCl followed by EDTA. Upon
sectioning, halves were attributed to two subgroups according to the
adhesive system used; whether Adper™ SE Plus or P90 System
Adhesive, and their corresponding resin composites Filtek™ Z250 and
Filtek™ P90, respectively. Two millimeter diameter resin composite
specimens were attached to the dentin substrate via adhesive system,
after which the whole assembly was stored in distilled water for 24 hours
until shear bond strength testing. A total of seven specimens were tested
for each subgroup. Shear bond strength testing was performed at a crosshead
speed of 0.5mm/min, using a universal testing machine. Shear bond
strength values, recorded in MPa, were tabulated and statistically
analyzed, through which results of this study were documented and
reasoned.
The results of this study showed that Adper™ SE Plus as a
methacrylate based adhesive recorded higher shear bond strength values
than its counterpart for silorane-based composites. In contrast, the
different dentin conditioners used caused a numerical increase in shear
Summary & Conclusions
101
bond strength values, when compared to control receiving no prior
conditioning. Conditioning performed via EDTA-NaOCl sequence
exceeded that of NaOCl-EDTA, NaOCl, EDTA, and control, in that
order. The highest mean shear bond strength was registered by subgroup
Adper™ SE Plus following NaOCl and EDTA, while the lowest was
recorded by P90 System Adhesive, surprisingly, that following NaOCl
and EDTA.
Conclusions:
Within the limitations of this investigation, the following
conclusions can be drawn:
1. The use of NaOCl, EDTA, and their combination as dentin
conditioners had a positive effect on resin-dentin shear bond
strength.
2. The methacrylate-based system was more positively affected
by the different dentin conditioners used, compared to the
silorane-based system, which was confined by its inherent
strength; except for EDTA followed by NaOCl which seems
to empower the silorane-based system.
3. The effect of NaOCl in increasing the bond strength was
more evident when preceding EDTA, in case of methacrylatebased
adhesive and the opposite was true in case of its
counterpart for silorane-based composite.
Summary & Conclusions
102
4. Resin-dentin shear bond strength of methacrylate-based
system was consistently greater than that of silorane-based
system, both with and without the investigated dentin conditioners.