Anti-Inflammatory Effect of Dental Pulpa Mesenchymal Stem Cell Exosomes Loaded Mucoadhesive Hydrogel on Mice with Dental Nickel Hypersensitivity

In this study, the anti-inflammatory effect of dental pulp mesenchymal stem cell (MSCs) exosomes loaded to mucoadhesive hydrogel is investigated in a dental nickel hypersensitivity murine model. After culture of dental pulp MSCs in the third passage MSCs are loaded to a mucoadhesive hydrogel based on chitosan, cross-linked with genipin and modified with catechol groups. A dental nickel hypersensitivity model is created by administering NiCl2 and 10 µg mL-1 lipopolysaccharide to 4-6 week-old Balb-c mice by intradermal injection. In mice treated with dental pulp MSC exosomes and exosomes in hydrogel, interferron gamma (IFN-γ) secreting CD4+T lymphocyte ratios significantly increase compared to the untreated group (p < 0.05). IFN-γ and interleukin 10 (IL-10) expression in buccal mucosa tissue sections and IFN-γ secreting CD4+T lymphocyte ratios are found to be significantly higher in mice treated with dental pulpa MSCs (DPMSCs) exosomes and DPMSCs exosomes in hydrogel compared to the untreated group (p < 0.05). According to flow cytometry results, IL-4 secreting CD4+T lymphocytes are found to be significantly decreased in DPMSCs exosomes group compared to dental nickel hypersensitivity group (p < 0.05). Administration of DPMSCs exosomes with mucoadhesive hydrogel may be an alternative to current medication in the treatment of dental nickel hypersensitivity.

Determination of radioactivity levels in feldspathic dental ceramics

Activity concentrations of 42 different feldspathic dental ceramic powders were determined using a gamma spectrometer with an HPGe detector. The average ²³⁸U, ²³²Th and ²²⁶Ra activity concentrations of the specimens were 126 ± 8 Bq kg^-1, 5.6 ± 0.5 Bq kg^-1 and 12.7 ± 1.2 Bq kg^-1, respectively. The average ⁴⁰K activity was found as 2855 ± 89 Bq kg^-1 ranging from 2252 ± 70 Bq kg^-1 to 3522 ± 110 Bq kg^-1 due to high potassium content in dental ceramics. None of the activity concentration measurements exceeded the limits by EC and ISO.