الفهرس 
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Abstract
The aim of this study was to compare the acid-etch
technique with sandblasting surface preparation technique on the
shear bond strength of orthodontic stainless steel bracket bonded
to enamel surface.
The sixty premolars were used in the shear bond strength
experiment. Twenty premolars were randomly divided into three
groups. The acid etching group I, the sandblasting (SB) group II,
and sandblasting and acid etching group III.
Sandblasting was done with 27 μm aluminum oxide with
PrepStartTM Device at 80 psi for 5 seconds and acid etching was
done with 37% ortho-phosphoric acid solution for 15 seconds in
this study.
The upper first premolars brackets were bonded to the
specimens. Each specimen was mounted in an Instron Universal
Machine and tested to failure in shear mode. After debonding, the
teeth were examined using stereomicroscope to determine the
percentage of adhesive remaining on the enamel after bracket
removal (ARI).
Shear bond strength determined in (MPa) at 1 mm/minute
Collected data were statistically analyzed for descriptive statistical
as well as significance of difference between different groups
using one-way analysis of variance ANOVA test followed by
multiple comparison post hoc test.
In the enamel surface evaluation study, five specimens from
each group was selected and scanned using Scanning Electron
Microscope at 500x, 1000x, 1200 and 2000x magnification after
different methods of surface treatment, to evaluate the effect of
the different methods of treatment on the enamel surface.