Glass-ionomer cement is primarily used for its ability to prevent caries due to sustained release of fluoride. In recent years, it has been proven as a carrier of various kinds of ions other than fluoride, and attention is paid to its property as a bioactive material. However, the release of ions from the material is not stable, and therefore, the reproducibility of the experiments is poor and variations are common. In this study, we investigated whether the presence or absence of stirring affects the stability and reproducibility of the reactions, aiming to optimize the research conditions for obtaining more consistent results. Our results suggest that the values obtained with continuous stirring are significantly more stable than the values obtained from stationary conditions.

We successfully prepared light-curing type fluorescent resins as orthodontic adhesives doped with tris(1,3-diphenyl-1,3-propanedionato)(1,10-phenanthroline)Eu(III) [Eu(DBM)₃Phen] by a photo- induced radical polymerization method. The transparent and almost colorless appearance of the composites under natural light is favorable for an esthetic dental product. The strong luminescence under near-UV light, especially when the content of Eu(DBM)₃ Phen is above 0.1 wt%, is promising for safe and complete removal of this adhesive after completing orthodontic treatments. We have also found that concentration quenching may occur around a concentration of 0.2-0.4 wt%. Based on the results obtained, in situ monomer polymerization can be applicable to Eu(DBM)₃Phen-containing adhesives. Although we are still investigating this proposed system, we conclude that the Eu(DBM)₃Phen-containing adhesives is a promising candidate for application to fluorescent orthodontic adhesives.

Many types of metal nanoparticles (NPs) are increasingly available for use as dental materials. The study evaluated the biofilm-growth inhibitory effects of silver NPs (AgNPs) and platinum NPs (PtNPs) against Streptococcus mutans (S. mutans). Two types of NPs, stabilized by polyvinylpyrrolidone (PVP), which has a negative surface charge, were used in this study. This study evaluated the effects of specific NPs, having two different core-metal compositions (Ag and Pt) and an identical surface-capping agent (PVP), on the disruption of initial biofilm growth. This was achieved using a biofilm-forming assay, and micromorphological examinations using a transmission electron microscope. The PtNPs inhibited a biofilm growth against S. mutans; however, no inhibitory effect was found in the case of the AgNPs. It was observed that the PtNPs adhered to the bacteria surface; however, no adhesion was observed in the case of the AgNPs. We speculate that the attachment of the NPs to S. mutans has an inhibitory effect on the biofilm formation during growth.

The objective of this study was to investigate the lung cancer risk in passive smokers using salivary exosome-derived microRNAs (mirs). Individuals were confirmed to be passive smokers by interviewing them using the Kano Test for Social Nicotine Dependence (KTSND) and measuring exhaled breath carbon monoxide (eBCO) level. Unstimulated saliva samples were collected from 25 students, and exosomes were isolated from salivary supernatants. Total RNA was isolated from the isolated exosome and washed and spun repeatedly using a filter cartridge to obtain the total RNA. Digital PCR was performed using mir-22, mir-150, and mir-155, which are related to lung cancer; mir-191 was used as the endogenous control. Salivary exosome samples considered positive by the carbon monoxide breath analysis monitor exhibited expression of mir-22, mir-150, and mir-155, that reportedly have increased expression in lung cancer. These findings indicate the possibility of investigating lung cancer risk in passive smokers using salivary exosome-derived mirs.

Cancer tissues strongly depend on the cancer microenvironment specifically observed around cancer, where immune cell infiltration and angiogenesis, as well as fibroblast proliferation, are induced in comparison with normal tissues. Various three-dimensional culturing methods for solid cancer cells have already been reported as in vitro experimental methods to reflect the characteristics of cancers. The spheroid cultures, constructed with cancer cells, should more accurately reflect the biological characteristics of cancers than two-dimensional cultures. However, solid cancers applicable to spheroid culturing are still limited. Previously, we compared the results of inflammatory cytokine Interleukin-6 (IL-6) between two-dimensional culture and spheroid culture with HSC-4 cells derived from human oral squamous cell carcinoma collected from the tongue. In the present study, besides IL-6, the expression of Matrix Metalloproteinase-9 (MMP-9), which plays an important role in the infiltration and metastasis of cancer cells surrounded by ECM, was examined by real-time RT-PCR, and the sizes of spheroids were observed over time.

Surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) with inorganic nanoparticles as desorption/ionization (DI) assisting materials, has been reported in order to decrease the background noises including matrix ions or matrix degradation products, especially in the region of < 500 Da. In this mass region, we can detect the existence of medical material components, drugs, and bio-related organic compounds. However, the mechanism of desorption/ionization of SALDI-MS is not clear. Therefore, in order to understand the correlation of desorption/ionization efficiency with molecular structures of analytes, the efficiencies of 20 common amino acids in SALDI-MS with TiO₂ nanoparticles are collected in positive ion mode. SALDI-MS with TiO₂ nanoparticles gives sodium ion adducted mass peaks. The ion intensity of amino acids is mainly determined by the same factors regardless of the desorption/ionization method in both MALDI and proton adducted SALDI but poorer linear correlation between the ion yield and the sodium ion affinity was found in our system.

The necrosis of cells and the mitochondrial activity of viable cells adhering to the surface of the root of teeth luxated due to trauma can influence the success rate of dental reimplantation. Cell preservation under conditions in which the osmotic pressure, pH and nutrients of the preservative solution are close to those of body fluid and internal body temperature may lead to good results. Furthermore, since there are many pathogenic microorganisms in the oral cavity, antibacterial and antifungal agents are needed. However, in clinical practice, luxated teeth are kept in milk, and many dentists preserve them in physiological saline at 4°C or room temperature. In dental care, luxation of teeth is often accompanied by trauma to the head and the teeth will be preserved for more than one hour.

In this study, we investigated a preservative solution containing an amino acid component and the temperature in the preservation of human periodontal ligament fibroblasts (HPLF). HPLF were cultured for 24 hours, then switched to peripheral parenteral nutrition (PPN) and preserved at 37°C. After preservation for one hour, mitochondrial activity was biochemically measured using an MTT assay. The influence of antiseptics, one antimicrobial and one antifungal agent, was also examined. High levels of mitochondrial activity were seen in HPLF preserved in PPN and at 37°C. This suggests that PPN is better than physiological saline and a temperature of 37°C is better than room temperature for HPLF preservation. Antiseptics did not affect HPLF preservation.