الفهرس 
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Abstract
This study evaluated the effect of dentin pre-treatment using bio-active glass particles on the micro-tensile bond strength of indirect restorations with immediate and delayed dentin sealing protocols.
Materials & Methods:
After the approval of the Scientific Research Ethics Committee, Faculty of Dentistry, Suez Canal University, seventy-two non carious human molars were collected for this study. They were embedded into acrylic resin blocks and a flat uniform mid dentin surface was exposed occlusally. The specimens were then randomly and equally divided into 3 groups according to the type of restoration and dentin sealing protocol whether it is direct (group R0) (Control group), or indirect restorations with immediate dentin sealing protocol (group R1) or indirect restoration with delayed dentin sealing protocol (group R2). These groups were further divided according to the dentin pre-treatment protocol, whether bioactive glass (Sylc™) was applied or not, then the composite resin blocks were cemented using resin cement.
The teeth were sectioned into bar shaped specimens for micro-tensile bond strength testing, half of them were tested after 24 hours while the other half was tested after 6 months of storage in artificial
Summary
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saliva. The mode of failure is classified as a percentage of cohesive (C), adhesive (A) or mixed (M) failures. Then the results were collected and analyzed statistically. Three-Way ANOVA was performed to compare the effect of study variables and their interaction on μTBS. One-Way ANOVA and Tukey’s HSD post-hoc test were conducted to compare μTBS values between different dentin pre-treatment groups and dentin sealing protocol at/ each testing time. Independent Student t-test was used to compare μTBS values between testing time within each dentin pre-treatment group.
Results:
Three-Way ANOVA showed that the study variables ‘restoration type’, ‘dentin-pre-treatment’ and ‘testing time’ had a significant effect on μTBS (P=0.003, P=0.009 and P<0.001, respectively). However, the interaction between them revealed no significant effect on μTBS. Although dentin pre-treatment using bioactive glass and immediate dentin protocol showed higher bond strength values, they were not significantly different. Dentin pre-treatment using bioactive glass did not significantly affect the bond strength immediately after 24 hours. However, after 6 months of aqueous media storage all groups showed a significant decrease in the μTBS values except for the groups subjected to dentin pre-treatment. Failure mode analysis showed a prevalence of adhesive failure in all tested groups.