This study aimed to evaluate the cytotoxicity and osteogenic potential of three sealers, including a strontium silicate-based sealer, C-Root SP (C-R), and two calcium silicate-based sealers, iRoot SP (i-R) and AH Plus Bioceramic Sealer (AHPbcs), compared with AH Plus (AHP) on MC3T3-E1 pre-osteoblasts. Standardized sealer discs were eluted in a culture medium to assess cytotoxicity using the CCK-8 assay at various dilutions (1:1, 1:2, 1:5, and 1:10). Osteogenic differentiation was evaluated by culturing cells in osteogenic medium supplemented with 1:5 diluted sealer extract. Alkaline phosphatase (ALP) activity was assessed with an ALP assay and staining on days 7 and 14. Mineralized nodule formation was observed using Alizarin Red S staining on day 21. Gene expression of osteogenic markers (ALP, COL1A1, and RUNX2) was examined by RT-qPCR. Differences were analysed using one-way/two-way variance analysis with the Tukey post-hoc test. Statistical significance was established at P < .05. C-R, i-R, and AHPbcs showed significantly higher cell viability than AHP (P < .001). All sealers exhibited cytotoxicity at higher concentrations (1:1 and 1:2 dilutions). ALP activity was significantly lower in cells exposed to AHP compared to cells exposed to C-R, i-R, and AHPbcs (P < .01). Cells exposed to C-R, i-R, and AHPbcs exhibited higher mineralized nodule formation than cells exposed to AHP. C-R, i-R, and AHPbcs enhanced osteogenic differentiation with higher osteogenic gene expression than AHP (P < .001). Within the limitations of the study, C-R, i-R, and AHPbcs were biocompatible with MC3T3-E1 pre-osteoblasts at lower concentrations and were able to enhance their osteogenic potentials. The strontium silicate-based sealer shows a favourable biological response and osteogenic activity in vitro, comparable to calcium silicate-based sealers, indicating its potential for clinical applications.

Enterococcus faecalis is an opportunistic microbial pathogen frequently associated with diverse infections, including those of the skin and teeth, as well as those from surgical wounds. It forms robust biofilms that are highly tolerant to most antimicrobials and first-line antibiotics. Therefore, investigating alternative strategies to eradicate its biofilms is a critical need. We recently demonstrated that trans-cinnamaldehyde (TC) potently kills E. faecalis biofilm cells and prevents biofilm recovery, and yet, the extreme hydrophobicity of TC hampers clinical translation. Here, we report that a complex of TC with an FDA-approved biosurfactant (acidic sophorolipid/ASL) significantly reduces the bacterial viability and biomass of E. faecalis biofilms, compared to TC alone. A confocal laser-scanning microscopic analysis demonstrated that the TC–ASL treatment significantly decreased the biofilm thickness and volume. In conclusion, our study highlights the anti-biofilm potential of the newly developed TC–ASL.

Background Dental pulp stem cells (DPSCs) have acquired noteworthy attention for their application in treating ischemic diseases and facilitating tissue regeneration. However, the host’s immune response following allogenic DPSC transplantation often handicaps the long-term survival of transplanted cells, thereby limiting the application of DPSCs in cell therapy. This study aims to investigate whether genetic modification can alleviate the immunogenicity of DPSCs. Methods Beta 2-microglobulin (B2M) and the class II histocompatibility complex transactivator (CIITA) were individually knocked down in DPSCs by lentiviral particles encoding short hairpin (sh) RNAs. The self-renewal capacity and pluripotency of DPSCs-shB2M (B2M silenced DPSCs) and DPSCs-shCIITA (CIITA silenced DPSCs) were evaluated by CCK8 and differentiation assays including osteogenesis, adipogenesis, and neurogenesis. The expression of HLA-I and HLA-II in DPSCs-shB2M and DPSCs-shCIITA after IFN-γ treatment were analyzed by western blotting, immunofluorescence, and flow cytometry. The function of genetically modified cells were assessed by leukocyte-mediated cytotoxicity and T cell proliferation assays. Results Western blotting, immunofluorescence, and flow cytometry revealed that DPSCs-shB2M and DPSCs-shCIITA exhibited impaired IFN-γ inducible HLA-I and HLA-II expression. There were no significant differences in the self-renewal capacity and pluripotency among DPSCs-shB2M, DPSCs-shCIITA, and control groups (p > 0.05). Lower leukocyte-mediated cytotoxicity and higher cell survival rates were found in DPSCs-shB2M and DPSCs-shCIITA groups compared to the control (p < 0.05). T cell proliferation was significantly inhibited in both DPSCs-shB2M and DPSCs-shCIITA groups (p < 0.05). Conclusion Genetic knockdown of B2M or CIITA in DPSCs substantially reduced their immunogenicity without compromising their stemness, thereby broadening the clinical application of DPSCs in cell therapy and tissue regeneration.