الفهرس 
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Abstract
72 Summary This study evaluated effect of different techniques of resin coat treatment during cementation after different protocols of dentin sealing. Materials & Methods: After the approval of the Scientific Research Ethics Committee, Faculty of Dentistry, Suez Canal University, one hundred 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 10 equal groups, whereas 8 experimental groups with immediate dentin sealing (IDS) and indirect restoration, 1 control group with delayed dentin sealing (DDS) and indirect restoration, and 1 control group with direct composite (n=10). One half of the experimental groups sealed using adhesive only (IDS-A) while the other half was sealed using adhesive and flowable resin composite (IDS+F). Each half was subjected to 4 different technique of resin coat treatment (Al2O3 airborne particle abrasion (APA), Al2O3 APA + Phosphoric acid (PA), Sylc APA, and Sylc APA + PA). The teeth were sectioned into bar shaped specimens for micro-tensile bond strength testing, half of each group was tested after 24 hours, while the other half was tested after 6 months of storage in artificial saliva. The mode of failure is classified 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 study groups at each testing time. Independent Student t-test was used to compare μTBS values between both testing times within each study group and to compare μTBS values between both IDS techniques with each resin coat treatment group.
Summary
73
Results:
Three-Way ANOVA showed that the study variables ‘testing time’, ‘IDS technique’, and ‘resin coat treatment’ had a significant effect on μTBS (P=<0.001, P<0.001 and P<0.001, respectively). The interaction between ‘testing time x IDS technique’, ‘testing time x resin coat treatment’ and ‘IDS technique x resin coat treatment’ had a significant effect μTBS (P<0.001, P=0.030 and P<0.001, respectively). While the interaction between ‘testing time x IDS technique x resin coat treatment’ revealed no significant effect on μTBS (P=0.595). The highest value was for group (Al2O3+PA), IDS-F groups showed the highest μTBS which was insignificant from each other or direct composite. Both Al2O3 APA showed significantly higher μTBS with IDS-F over IDS-A, while (Sylc only) showed no difference between IDS-F and IDS-A. DDS group presented the significantly lowest μTBS values compared to all groups. Storage for 6 months significantly reduced the μTBS values of all groups, for groups IDS-F, the significantly highest μTBS for the (Al2O3+PA), while for group IDS-A, the highest μTBS was for (Sylc) only group. DDS still presented the lowest values. Failure mode analysis revealed that with high μTBS values, mixed and cohesive failures were prominent over adhesive, while lower μTBS values were associated with a prevailing adhesive failure. After 6 months, prevalence of adhesive failure in all tested groups except group IDS-A (Sylc), where mixed failures were of high prevalence.