الفهرس 
I. INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The aim of this study was to compare the shear bond strength of the conventional adhesive and a new self-etch primer/adhesive system under different enamel surface conditions.
Eighty six recently extracted human maxillary premolars were collected from patients under 18 years old, seeking orthodontic treatment at the out patient clinic of the Orthodontic Department, Faculty of Dentistry, Ain Shams University.
Eighty premolars were used to test the shear bond strength. These premolars were randomly divided into 2 equal groups. In group I (N=40), Monolok2 conventional adhesive was used to bond brackets to the enamel surface with acid etching. In group II (N=40), Brajen Unibond self-etch primer/adhesive was used to bond brackets to the enamel surface without acid etching. Each group was further subdivided into 4 equal subgroups according to enamel surface treatment.
The remaining six teeth were used in the enamel surface treatment test. They were randomly divided into three groups, two were examined to show the polished untreated enamel surface (group III), two were examined to show the effect of phosphoric acid etchant on enamel (group IV) and two were examined to show the effect of self etching primer on enamel (group V).
The premolar brackets were bonded to the specimens according to the manufacturer instructions. Each specimen was mounted in an Instron Universal Testing 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). In the enamel surface evaluation study, the teeth were examined using scanning electron microscope.
Results revealed highly significant differences between subgroups in group I and also in group II. When comparing the same subgroups in group I and group II, they showed significant difference in their shear bond strength except for subgroup IC and subgroup IIC.
Comparison of the ARI scores indicated the presence of significant differences in their distribution frequencies within different subgroups in group I. However, different subgroups in group II indicated no significant differences in their distribution frequencies.
The enamel surface showed an etching pattern that was more effective and distinct with the use of phosphoric acid etchant when examined under scanning electron microscope. The self-etch primer showed an uneven, “coral-like” etching pattern.