Biocompatibility of a High-Plasticity, Calcium Silicate-Based, Ready-to-Use Material

The Bio-C Sealer is a recently developed high-plasticity, calcium-silicate-based, ready-to-use material. In the present study, chemical elements of the materials were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The biocompatibility of the Bio-C Sealer was investigated using cytotoxicity tests and histological responses in the roots of dogs’ teeth. XRD, SEM, and FTIR produced hydrated calcium silicate in the presence of water molecules. In addition, FTIR showed the formation of calcium hydroxide and polyethylene glycol, a dispersing agent. The 1:4 dilutions of Bio-C Sealer presented weaker cytotoxicity than the Calcipex II in an in vitro system using the V-79 cell line. After 90 d, the periradicular tissue response of beagle dog roots was histologically evaluated. Absence of periradicular inflammation was reported in 17 of the 18 roots assessed with the Bio-C Sealer, whereas mature vertical periodontal ligament fibers were observed in the apical root ends filled with the Bio-C Sealer. Based on these results and previous investigations, the Bio-C Sealer is recommended as an effective root-end filling material. These results are relevant for clinicians considering the use of Bio-C Sealer for treating their patients

Effectiveness of Near-Infrared Light Photodynamic Therapy on Oral Cancer Cells

Aim or Purpose: The purpose of this study is to obtain basic data for PDT of human squamous cell carcinoma cell line (HSC-3) using the photosensitizer (Ce6), up-conversion particle (UC) and laser with near-infrared light (long wavelength) in vitro and in vivo. Materials and Methods: After using MTT Assay to determine a relatively suitable concentration combination, HSC-3 cells were treated with PDT with Ce6 and UC. Cell death by Calcein AM assay, apoptosis by FITC-Annexin V assay, intracellular singlet oxygen (Si-DMA for Mitochondrial Singlet Oxygen Imaging) and reactive oxygen species (ROS Assay Kit-Highly Sensitive DCFH-DA) were examined. HSC-3 cells were injected into the right lingual border of BALB/c nu/nu nude mice (4-weeks-old, female) and treated with PDT after 2 weeks later, then thinly sliced specimens were observed with hematoxylin-eosin staining, apoptosis staining and immunohistochemical staining using anti- cytokeratin (CK)17 antibody. Results: PDT with 0.5ng/μL Ce6 and 0.1ng/μL UC inhibits the cell proliferation of HSC-3 (P<0.05). PDT leads to an increase of intracellular singlet oxygen and ROS amount and apoptosis has occurred (P<0.05). When PDT with Ce6 and UC was performed on the lingual border of nude mice, CK17 positive carcinoma foci were observed and a part of the foci composed of HSC-3 had disappeared, apoptosis was detected in other parts. Conclusions: These results suggest that PDT with long wavelength laser can inhibit the proliferation of cancer cells and lead them to apoptosis

Potential UV-Protective Effect of Freestanding Biodegradable Nanosheet-Based Sunscreen Preparations in <i>XPA</i>-Deficient Mice

Xeroderma pigmentosum (XP) is a rare autosomal recessive hereditary disorder. As patients with XP are deficient in nucleotide excision repair, they show severe photosensitivity symptoms. Although skin protection from ultraviolet (UV) radiation is essential to improve the life expectancy of such patients, the optimal protective effect is not achieved even with sunscreen application, owing to the low usability of the preparations. Nanosheets are two-dimensional nanostructures with a thickness in the nanometer range. The extremely large aspect ratios of the nanosheets result in high transparency, flexibility, and adhesiveness. Moreover, their high moisture permeability enables their application to any area of the skin for a long time. We fabricated preparations containing avobenzone (BMDBM) based on freestanding poly (L-lactic acid) (PLLA) nanosheets through a spin-coating process. Although monolayered PLLA nanosheets did not contain enough BMDBM to protect against UV radiation, the layered nanosheets, consisting of five discrete BMDBM nanosheets, showed high UV absorbance without lowering the adhesive strength against skin. Inflammatory reactions in XPA-deficient mice after UV radiation were completely suppressed by the application of BMDBM-layered nanosheets to the skin. Thus, the BMDBM layered nanosheet could serve as a potential sunscreen preparation to improve the quality of life of patients with XP