الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Less application steps, reduce manipulation time and technique
sensitivity, and may so improve bonding effectiveness in routine clinical
practice. Universal adhesives were recently introduced. This study was
conducted to evaluate micro shear bond strength, resin /dentin interface and
nanoleakage of newly introduced different multi-mode adhesives on dentin.
A total of 180 anterior bovine teeth were extracted from sacrificed
bovine jaws. The labial surface of the cervical half was ground flat to remove
enamel and expose an area of nearly 8mm diameter of dentin using 600 grit
sand papers. The specimens were divided into thirty groups (n=6) according
to the three levels of the study; Level 1: adhesive system (Peak U, G-aenial
B, Futura U, Single Bond U and All Bond U). Level 2: application mode
(self etching, etch and rinse dry bonding and etch and rinse wet bonding)
Level 3: storage period (24 hours and one year). All the specimens will be
subjected to micro shear bond strength testing using Universal Testing
Machine. Another total of 120 bovine teeth of each previous experimental
group n=4 were prepared and used for evaluation of the resin/dentin interface
and naoleakage.
Results of micro shear bond strength testing showed that adhesive
systems and storage periods had a significant effect on the micro shear bond
strength to bovine dentin (P=0.0001). On the other hand, application modes
had no significant effect on the micro shear bond strength to bovine dentin
(p=0.144). Evaluation of SEM micrographs of resin/dentin interfaces
bonded with different universal adhesives supported the bond strength data.
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Conclusions:
Under the limitations of this study, the following conclusions could be
drawn:
1- Bond strength of multi mode adhesives is affected by the
adhesive composition and acidity.
2- The effect of application mode on bond strength is insignificant,
regardless to other factors. However, the interaction of adhesive
type, mode of application and storage time is highly significant.
3- Durability of bond strength is affected by adhesive type.
4- Application of etching step prior to multi mode adhesives
improves their resin/dentin penetration pattern.
5- Nanoleakage is dependent on the interaction between adhesive
composition, application mode and storage period.
Recommendations:
1- Further studies on different substrates, such as carious dentin in
association with in vivo tests are needed to assess the long term
clinical behavior of new multi mode adhesives.
2- Further evaluating tests, such as water sorption, solubility and
degree of conversion are recommended to correlate between
adhesives performance over different storage periods.
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