Introduction: The purpose of this study was to compare the Vickers hardness number (VHN) and depth of cure of two types of bulk fill composites in high, low and soft light Curing modes. Materials & Methods: In this experimental study, 60 cylindrical samples were fabricated from two types of bulk fill composites (Tetric N-Ceram and X-tra fil) in a Teflon mold with one semi-circular notch. Then, the samples were randomly divided into the following three subgroups based on the Curing modes (high, low and soft) and were light-cured. The samples were removed from the molds, and their VHN and depth of cure were measured. Data were analyzed using One-way ANOVA and Tukey’ s post hoc test at the significance level of P<0. 05. Results: The mean VHN of the X-tra fil composite was significantly higher than that of Tetric N-Ceram composite (P<0. 001). The depth of cure of X-tra fil composite was also significantly higher than that of Tetric N-Ceram composite in high and soft Curing modes (P<0. 001). Conclusion: According to the current results, X-tra fil composite is a convenient material for the restoration of deep cavity in posterior teeth compared with Tetric N-Ceram.

Today concrete is most generally utilized development material in the world due to its strength and sturdiness properties. To attain good strength, Curing of concrete is important so we introduce the concept of self-Curing concrete rather than immersion or sprinkle Curing to avoid water scarcity. It was observed that water solvent polymers can be utilized as a self-Curing agent, i. e. polyethylene glycol (PEG-400). In the present study, to discover the effect of admixture polyethylene glycol (PEG-400) on compression strength, split tensile strength and flexural strength, adding the diverse rate of PEG-400 to the weight of cement from zero to two percentages as the measurement of the Curing agent is done. The test results were studied for M30 concrete mix. The optimum percentage of PEG-400 was found to be 1% for compressive and Split Tensile Strength. If the dosage of PEG-400 increases to more than 1%, there is a decline in compressive and split tensile strength. However, the optimum percentage of PEG-400 for flexural strength was found at 0. 5%. If we increase the dosage of PEG-400 more than 0. 5%, there is reduction in strength of flexural strength.

Statement of the Problem: One of the problems with light-cured composite resins is the limitation and inadequate depth of Curing and polymerization, resulting in low surface mi-crohardness and restoration failure. Purpose: The present study aimed to compare the surface microhardness of two different bulk-fill composite resins and one conventional composite resin using the Vickers micro-hardness test. Materials and Method: In the present in vitro study, 108 samples from two different bulk-fill composite resins (Tetric N Ceram and Xtrafil) and one conventional composite resin (Filtek Z250) were prepared in metallic molds (2×4×10 mm) (n=36 for each composite resin). Six samples from each composite resin (n=6) underwent a hardness measurement test at specific depths (0. 1, 1, 2, 3, 4 and 5mm). The samples were then stored at 37º C for 24 hours, followed by a microhardness test at the depths mentioned above. Results: In all the composite resin samples, microhardness decreased with an increase in depth. The highest microhardness was recorded in Filtek Z250, followed by Xtrafil, with no significant difference. The lowest microhardness was recorded in Tetric N Ceram bulk-fill. Both bulk-fill composite resins at all the depths exhibited depth-to-surface standard micro-hardness (>80%). Conclusion: According to the results, both evaluated bulk-fill composite resins exhibited favorable surface microhardness up to a depth of 5 mm.