الفهرس 
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Abstract
The aim of this in vitro study was to evaluate the marginal adaptation and
push out bond strength of four furcation perforation repair materials which are:
Retro MTA, TotalFill, Biodentine, and Zirconomer.
In the present study forty extracted mandibular molars were collected and
scaled to be completely clean from any external fragments. Access cavity was done
to all teeth under the visual aid of dental loupes.
Teeth were decoronated three mm above the CEJ, and roots was amputated
3 mm below the furcation using a water cooled diamond sectioning disc, the
measurements were done using digital caliper. In each sample a perforation was
done in the center of the furcation area using a round bur size 4.
Repair materials were mixed according to the manufacturer’s instructions
and placed inside the prepared furcation perforation using map system.
Marginal adaptation was measured first using Enviromental scanning
electron microscope (ESEM) The specimens were mounted on coded stubs and each
sample was scanned under 120X for obtaining image for the whole defect and then
the gap was measured using ImageJ software.
Push out bond strength was tested for all the materials after obtaining the
marginal gap. Push out bond strength was tested for all samples using universal
testing machine Instron.
The results of this study showed the following:
A- Marginal adaptation and push out bond strength between groups:
- The highest of marginal gap (in µm) was reported with Zirconomer group,
followed by Retro MTA group, TotalfiL group, and the lowest marginal
gap (in µm) was noted with Biodentine group
Summary and conclusion
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- Retro MTA group recorded significant higher marginal gap than TotalfiL
and Biodentine groups.
- Zirconomer group recorded significant higher marginal gaps than Retro
MTA group, Biodentine group, and TotalfiL group
- TotalfiL group recorded significant higher marginal gap than Retro MTA
and Biodentine groups.
- The highest push out bond strength was reported with Biodentine group,
followed by TotalFill group, then Retro MTA group, and the lowest push
out bond strength was noted with Zirconomer group
- There was a significant difference between TotalfiL group and
Zirconomer group and between Biodentine group and Zirconomer group.
However, no significant difference was noted between other groups.
B- Correlation between Push out bond strength and Marginal adaptation:
- There was a significant negative correlation between push out bond
strength and marginal gap (Pearson correlation= - .362, p=.049)
- This means that push out bond strength significantly decreased when
marginal gap increased, vice versa.