Aims: To compare and evaluate the bonding ability of bulk-fill resin composite (RC) to four different liners: Biodentine (BD), TheraCal (TLC)-a novel resin-modified calcium silicate cement, resin-modified glass ionomer cement (RMGIC) and conventional glass ionomer cement (GIC) using a universal silane-containing adhesive and characterizing their failure modes. Materials and Methods: Forty extracted intact human premolars with occlusal cavity (4-mm diameter and 2-mm height) were mounted in acrylic blocks and divided into four groups of (n=10 samples) each based on the liner used as group I; (BD), group II; (TLC), group III; (RMGIC) and Group IV; (GIC). Bulk-fill composite buildup of 3 mm diameter and 5 mm height was then bonded to each sample using universal adhesive. Shear bond strength (SBS) analysis was performed using materials testing machine at a cross-head speed of 0.5 mm/min. Statistical Analysis: Statistical analysis was performed with one-way analysis of variance (ANOVA) and Tukey's post hoc test for numerical data while chi square test for categorical one. Results: One-way analysis with ANOVA revealed significant difference in bond strength values between the different groups (p<0.001). The observed modes of failure were predominantly cohesive in Biodentine, TheraCal and GIC groups while RMGIC showed majority of mixed and minority adhesive failures. Conclusions: Biodentine demonstrated lower bond strength values when immediately bonded to bulk-fill resin composite compared with RMGIC, TheraCal and GIC groups (2906)

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Twenty freshly extracted non-carious human molars were used. The mineral content of all teeth was initially assessed using EDX. Teeth were then divided randomly into two groups each containing ten samples. All teeth were placed in demineralizing agent after which one group (I) was remineralized using egg shell solution while the other group (II) was remineralized using fluoride varnish (Proshield, President dental Germany). This process was held in a pH cycling mode.Regarding mineral content specimens of both groups were initially assessed (base line measurements), then reassessed directly after demineralization, three days from remineralization and at the end of seven days remineralization period. Results were as follow : Regarding Ca wt % and comparing the two groups there was no statistical significance at base line measurements, after demineralization and after three days from remineralization. Meanwhile after seven days remineralization group (I) demonstrated statistically significant lower mean Ca atomic wt % than group (II). Regarding phosphorus atomic wt % for measurements of base line, after demineralization and after remineralization there was no statistical significance between the two groups. Regarding the effect of time for Ca wt % and after seven days group (I) showed non statistically significant decrease in Ca wt % compared to that at base line, while group (II) showed non statistically significant difference from the value measured at base line. For the P wt % and after seven days both groups demonstrated non statistically significant lower mean values compared to base line data.

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60 non carious, extracted human teeth were used in this study, for evaluating the shear bond strength of composite resin to dentin using the all in one adhesive system (prompt L-Pop). All teeth were divided into four groups to represent four different surface substrate inclinations. Analysis of variance (ANOVA) test was performed to assess the presence of significant differences in mean shear bond strengths at different surface substrate inclinations (whether the different inclinations of surface substrate produced significant effect on the mean shear bond strengths). Student-Newman-Keuls test and the least significant difference procedure were used for pair wise comparison between means to find out which means were significantly different. The above tests were separately performed for the groups of specimens that were immediately investigated; those that were stored for one week and those that were stored for one month. ANOVA test, also, was performed to study the effect of time on the shear bond strengths of all groups of specimens at each substrate inclination through all time periods. results: Within each time period, the results revealed that different inclinations of surface substrate produced statistically significant changes in the mean shear bond strengths, (P < 0.001). The mean shear bond strengths of the group of specimens to which the application of the adhesive system was performed with the occlusal plane of the lower jaw of the phantom head parallel to the floor (group A 4 ), were significantly higher than the other 3 groups (P < 0.05). Group A 2 (the group of specimens to which the application of the adhesive system was performed with the occlusal plane of the upper jaw of the phantom head making a forty five degree angle with the floor), came next. The ranking of groups according to the mean shear bond strengths was : A 4 > A 2 > A 1 > A 3 . Regarding the effect of storage time (one week and one month) on the mean shear bond strengths of the adhesive system used, it was found that there were no significant differences among the shear bond strengths of any of the tested groups, at any substrate inclination, through all time periods (T 0 , T 1 , T 2 ) (P > 0.05).