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.

Oral squamous cell carcinoma (OSCC) is a common malignancy in the oral cavity. Photodynamic therapy (PDT) is a new alternative for the treatment of diseases using photosensitizers (PS) and light. In this study, we used a photosensitizer complex (Ce6-MnNPs—Chlorin e6 combined with up-conversion nanoparticles NaYF₄:Yb/Er/Mn) to investigate the therapeutic effectiveness of this treatment against oral cancer cells. We also investigated the mechanism of action of near-infrared light PDT (NIR-PDT) combined with the Ce6-MnNPs. After determining a suitable concentration of Ce6-MnNPs using an MTT assay, human oral squamous cell carcinoma cells (HSC-3) were treated with NIR-PDT with Ce6-MnNPs. We examined the characteristics of Ce6-MnNPs by transmission electron microscopy (TEM); a zeta potential and particle size analyzer; Fourier-transform infrared spectroscopy (FTIR); cell viability by MTT assay; and apoptosis by FITC-Annexin V/PI assay. The mitochondrial membrane potential (MMP), apoptosis-related mRNA level (Bax and Bcl-2) and p53 protein were also researched. NIR-PDT with 0.5 ng/µL Ce6-MnNPs inhibited the proliferation of HSC-3 (p < 0.05). After treatment with NIR-PDT, changes in the mitochondrial membrane potential and apoptosis occurred (p < 0.01). The ratio of Bax/Bcl-2 and p53-positive cells increased (p < 0.01). These results suggest that this treatment can induce apoptosis of oral cancer cells.

Purpose This study aimed to compare the clinicopathological features of stage I–II oral squamous cell carcinoma (OSCC) between adolescents and young adults (AYAs) and older patients, and to identify prognostic factors in AYA OSCC. Methods Forty-eight AYA patients aged 15–39 years and 69 older patients aged ≥ 65 years with surgically treated stage I–II OSCC were retrospectively analyzed. Histological evaluation, survival analysis, immunohistochemistry for p53, p16, and MTAP, high-risk HPV RNA in situ hybridization, and fluorescence in situ hybridization for CDKN2A and MTAP were performed. Results Compared with older patients, OSCCs in AYAs were more frequently located on the tongue (93.7% vs. 47.8%) and more often exhibited a superficial spreading growth pattern (60.4% vs. 31.8%). AYA tumors more frequently showed modified WPOI-1, high tumor budding, and abnormal p53 immunophenotypes (85.4% vs. 68.1%). AYA patients showed significantly better overall and disease-free survival than older patients. Within the AYA group, depth of invasion (DOI) > 5 mm was associated with distant metastasis and poorer overall and disease-free survival. Postoperative lymph node metastasis occurred in 31.2% of AYAs. Univariable analysis suggested that clinical stage II, tumor thickness > 5 mm, DOI > 5 mm, and tumor budding scores 1–2 were associated with postoperative lymph node metastasis. Molecular status, including p53, p16/CDKN2A, and MTAP, did not provide robust prognostic stratification. Conclusion Early-stage AYA OSCC exhibits distinct clinicopathological features. DOI was the strongest prognostic indicator, whereas clinical stage, tumor thickness, and tumor budding may provide additional prognostic information regarding the risk of late nodal metastasis.