In this research, we aimed at improving the setting properties and biocompatibility of the mineral trioxide aggregate‐like cements while maintaining the main chemical formula. Consequently, chitosan and zirconium oxide were added to the cement instead of bismuth oxide to improve the mechanical behavior, limit the possible toxicity, and enhance the bioactivity of the cements. Adding zirconia resulted in a shorter setting time and adding chitosan contributed to the setting time, mechanical strength, and biocompatibility at the same time. Thus, cements containing both chitosan and zirconia had the shortest setting time, highest compressive strength, and apatite‐forming ability.

Objectives: This study investigated the indirect effect of calcium-enriched mixture (CEM) cement and mineral trioxide aggregate (MTA), as 2 calcium silicate-based hydraulic cements, on human dental pulp stem cells (hDPSCs) through different dentin thicknesses. Materials and Methods: Two-chamber setups were designed to simulate indirect pulp capping (IPC). Human molars were sectioned to obtain 0.1-, 0.3-, and 0.5-mm-thick dentin discs, which were placed between the 2 chambers to simulate an IPC procedure. Then, MTA and CEM were applied on one side of the discs, while hDPSCs were cultured on the other side. After 2 weeks of incubation, the cells were removed, and cell proliferation, morphology, and attachment to the discs were evaluated under scanning electron microscopy (SEM). Energy-dispersive X-ray (EDXA) spectroscopy was performed for elemental analysis. Alkaline phosphatase (ALP) activity was assessed quantitatively. The data were analyzed using the Kruskal-Wallis and Mann-Whitney tests. Results: SEM micrographs revealed elongated cells, collagen fibers, and calcified nucleations in all samples. EDXA verified that the calcified nucleations consisted of calcium phosphate. The largest calcifications were seen in the 0.1-mm-thick dentin subgroups. There was no significant difference in ALP activity across the CEM subgroups; however, ALP activity was significantly lower in the 0.1-mm-thick dentin subgroup than in the other MTA subgroups (p < 0.05). Conclusions: The employed capping biomaterials exerted biological activity on hDPSCs, as shown by cell proliferation, morphology, and attachment and calcific precipitations, through 0.1-to 0.5-mm-thick layers of dentin. In IPC, the bioactivity of these endodontic biomaterials is probably beneficial.

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Background: Color change is one major drawback of tooth-colored resin-based restorations. Objectives: This study aimed to assess the color stability of three commonly used resin-based restorative materials upon exposure to tea and coffee. Materials and Methods: Discs were fabricated from Spectrum TPH (Dentsply/Caulk), Denfil (Vericom), and Filtek Z250 (3 M) microhybrid composites and immersed in coffee and tea solutions for two hours on the first day and the whole of the second, third, and fourth days. The color was assessed visually and recorded using the Lobene Stain Index after each period of immersion. The color change of the three composite resins was compared using the Kruskal-Wallis test, Mann-Whitney U test, and Friedman test. The level of significance was set at 0.05. The Cohen's Kappa was also calculated to assess inter-rater agreement. Results: The three composite resins showed statistically significant color changes after four days of immersion in a coffee solution (P = 0.014), but their color change in the tea solution was not significant (P > 0.05). A comparison of color changes in the composites after one (two hours) and four days of immersion in tea and coffee solutions revealed a significant difference in color changes between Spectrum TPH and the other two composites (P < 0.001). Conclusions:The three microhybrid composites used in this study showed variable color stability upon exposure to a coffee solution. The color stability of Spectrum TPH was inferior to that of Denfil and Filtek Z250.