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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Background and objective: Finishing and polishing techniques have great importance on the long-term success and aesthetics of the composite restorations. This study aimed to investigate the effect of three finishing and polishing systems on surface roughness and color changes of four different posterior composites. Materials and Methods:Four different posterior composites, nanohybrid, nano-fill, sonicactivated bulk-fill and microhybrid resin-based composite, and three different finishing and polishing systems, Sof-Lex discs, Astropol® and TOR VM discs were used in the study. The disc specimens (15 disc for each resin composite with total n=60) were 10 mm in diameter and 2 mm in height. Before and after finishing and polishing procedure, surface roughness was measured with a profilometer device and the Ra values were recorded. Color changes was examined using spectrophotometer and (ΔE) values were calculated. Data were tabulated and statistically analyzed using analysis of variance and Tukey's test at significance level of p<0.05.Results: There was no significant difference among the composite resins or the finishing and polishing systems used on surface roughness (p > 0.05) although all composites showed a smoother surface after finishing and polishing procedures. As regard to color changes (ΔE) statistically significant difference was found between composite groups and finishing and polishing system used (p < 0.05). A direct correlation between Ra and ΔE values was found.Conclusions: 1.surface roughness and color stability of resin composite restorations depend mainly on the material compositions and polishing procedure. 2. The effectiveness of the polishing systems was material dependent. 3. Among the material tested, Nanohybrid presented the smoothest surfaces and the least color changed material. 4. The polishing systems in this study, the best system was the TOR VM discs polishing system with respect to the surface roughness and color changes values. 5. Developments in finishing and polishing systems are important for the creation of ideal restorations and are associated with the increased clinical success of dental practitioners

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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Background:In clinical practice, the restoration of non-carious cervical lesions is a challenge, because most of the time the cervical margin is located in cementum or dentin. This characteristic makes the cervical margin more susceptible to microleakage, causing marginal stains, postoperative sensitivity and recurrent caries.Aim: To compare the microleakage and bond strength for teeth restored with Activa Bioactive restorative and nanohybrid composite resin Materials and methods: Twenty permanent premolars were selected with class V cavities for microleakage, and 20 permanent premolars were selected for shear bond strength. Microleakage was checked using dye penetration method under digital microscope Universal testing device was used to assess the shear bond strength. Leakage scores, mean and standard deviation values for shear bond strength were calculated from the recorded values. For numerical data student t-test was performed to detect the significance between both groups. For categorical data analysis Chi square test was done.Results; There was non-significant difference between ACTIVA bioactive restorative group and nanohybrid composite resin group in both parameters; leakage and bond strength Conclusion: Based on the results of the present study, the type of restorative material did not appear to have a significant influence on microleakage or bond strength KEYWORD: Active Bioactive, Non-Curious Cervical Lesions, Microleakage (4050)

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Purpose: The purpose of this study was to evaluate the effect of three different base materials (GIC, Chemfill rock, and SDR,) on microleakage, fracture resistance, and color stability of two ceramic inlays (E max and Vita suprinity). Materials and methods: Sixty extracted premolars were prepared for Class II inlay MOD. For microleakage test thirty teeth divided into three groups (n=10); group (A): restored with (GIC). Group (B): restored with Chemfill rock. Group (C): restored with SDR. After thermocycling the microleakage was evaluated by scores. For evaluation of fracture resistance and color stability, the remaining thirty teeth were divided into two groups(n=15) Group (1): The teeth restored with Emax inlay. Group (2): restored with Vita Suprinity inlay. Each group was subdivided into three subgroups(n=5); Subgroup (I): based with (GIC). Subgroup (II): based with Chemfill Rock. Subgroup (III): based with SDR. Results: For microleakage test; SDR base had stage zero leakage, leakage was higher in GIC base. For fracture resistance test; there is statistically significant high mean of fracture resistance in SDR base. On the other hand there is no statistically significant difference as fracture resistance between E-max, and Vita Suprinity restoration. For color stability test; there is statistically significant difference high mean of color difference in SDR base with p-value <0.05. On the other hand there is no statistically significant difference between E-max, and Vita Suprinity restoration. Conclusion: SDR is the best base regarding microleakage, color stability and fracture resistance. While there is no significant difference between Emax and Vita Suprinity restorations. in color stability and fracture resistance.