Background. Resin composites have various applications. At the same time, they have some drawbacks, such as polymerization shrinkage. Conventional composites are polymerized in 2-mm thick layers. However, in posterior restoration, the 2-mm depth of cure is not satisfactory. To find a solution, resin composites have been vastly improved in terms of fillers, matrix and initiators.Objectives. To evaluate polymerization properties and physical characteristics of fiber-reinforced composites and compare them with bulk-fill composites that are designed for large posterior restorations. Materials and methods.Samples were prepared from each resin composite. The 3-point bending test was performed to evaluate the flexural strength of all composites. The depth of cure of the composite from 1 mm to 4 mm of depth was analyzed using Vickers hardness test (VHN). To analyze the degree of conversion, Fourier-transform infrared spectroscopy (FTIR) of the top and bottom surfaces of the samples with 4-mm thickness was calculated. The data were analyzed using one-way analysis of variance (ANOVA) test followed by post hoc test (95% confidence interval (95% CI)).Results. The Filtek showed the highest flexural strength followed by everX and X-tra fil. At 1-mm depth, X-tra fil had the highest and Gradia had the lowest microhardness. At the 4-mm depth, the microhardness trend was as follows: everX > Filtek > X-tra fil > Gradia > Beautifil. The everX composite had the lowest reduction of the degree of conversion at 4-mm thickness, which showed a significant difference in comparison with Filtek, Gradia and X-tra fil composites. Conclusions.Based on the results of our study, it can be concluded that the fiber-reinforced composite everX showed more favorable results regarding polymerization properties, such as the degree of conversion and the depth of cure. However, the flexural strength results in Filtek were better than those in everX.

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Introduction: Broad neural circuits originate from the hypothalamic arcuate nucleus and project to many parts of the brain which are related to pain perception. Insulin receptors are found in the arcuate nucleus. Since nociception may be affected in type 1 diabetes, the present study aimed to investigate the intra-arcuate nucleus insulin role in pain perception in streptozotocin (STZ)-induced diabetic and healthy rats. Methods: Regular insulin was microinjected within the arcuate nucleus and the pain tolerance was measured using the hot plate and the tail-flick apparatus in diabetic rats. Results: The results showed that the arcuate nucleus suppression with lidocaine could increase thermal nociception in non-diabetic animals. Also, insulin within the arcuate nucleus decreased the acute thermal pain perception in these animals. STZ-induced diabetes produced hypoalgesia which the latency of these tests, progressively increased over time after induction of diabetes. Also, in the same animal group, intra-arcuate injection of insulin reduced the latency of nociception. Conclusion: Intra-arcuate insulin has paradoxical and controversial effects in healthy and diabetic rats’ nociception. These effects seem to be due to the insulin effect on releasing pro-opiomelanocortin and its deriv