Long non-coding RNA XIST promotes the malignant features of oral squamous cell carcinoma (OSCC) cells through regulating miR-133a-5p/VEGFB.

OBJECTIVE: Oral squamous cell carcinoma (OSCC) represents a frequently seen oral cavity malignancy, and the mechanisms of its occurrence and development remain unclear. The present work examined the expression and biological function of long non-coding RNA (lncNRA) XIST (X-inactive specific transcript) in OSCC cells and tissues. STUDY DESIGN: A total number of 50 OSCC and paired non-carcinoma tissue samples were collected in this study. Gene expression levels in cancer tissues and cells were quantified by RT-qPCR. In addition, gain- and loss-of-function experiments were conducted to investigate the biological roles of XIST as well as its downstream targets in OSCC cells. RESULTS: XIST was upregulated in OSCC cells and tissues, which predicted a poorer prognostic outcome in OSCC patients. Silencing XIST inhibited the growth and invasion of OSCC cells and triggered apoptosis. miR-133a-5p was identified as a downstream target of XIST, which was downregulated in OSCC tissues. miR-133a-5p mediated the effect of XIST by targeting VEGFB. VEGFB overexpression rescued the inhibitory effects of XIST silencing on cell growth, invasion and migration. CONCLUSION: Taken together, the above data indicates that XIST serves as an oncogenic factor to enhance the growth and invasion of OSCC cells by targeting the miR-133a/VEGFB axis.

Effect of MicroRNA-138 on Tumor Necrosis Factor-Alpha-Induced Suppression of Osteogenic Differentiation of Dental Pulp Stem Cells and Underlying Mechanism.

High doses of tumor necrosis factor-α (TNF-α) suppress osteogenic differentiation of human dental pulp stem cells (hDPSCs). In the present study, we aimed to explore the role and potential regulatory mechanism of microRNA-138 (miR-138) in the osteogenic differentiation of hDPSCs after treatment with a high dose of TNF-α. The hDPSCs were cultured in osteogenic medium with or without 50 ng/ml TNF-α. The miR-138 levels were upregulated during osteogenic differentiation of the hDPSCs following TNF-α treatment. The miR-138 overexpression accelerated but miR-138 knockdown alleviated the TNF-α-induced suppression of the alkaline phosphatase activity, calcium deposition, and protein abundance of dentin sialophosphoprotein, dentin matrix protein 1, bone sialoprotein, and osteopontin during osteogenic differentiation induction of hDPSCs. Additionally, miR-138 overexpression accelerated but miR-138 knockdown alleviated the suppression of the focal adhesion kinase- (FAK-) extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway during osteogenic differentiation induction of hDPSCs under TNF-α treatment. In conclusion, miR-138 accelerates TNF-α-induced suppression of osteogenic differentiation of hDPSCs. Inactivation of the FAK-ERK1/2 signaling pathway may be one of the mechanisms underlying the effect of miR-138. Inhibition of miR-138 expression may be a strategy to weaken the inhibitory effect of high-dose TNF-α on the osteogenic differentiation of hDPSCs.

Effect of sodium ascorbate on degree of conversion and bond strength of RealSeal SE to sodium hypochlorite treated root dentin.

The aim of this study was to investigate the effect of sodium ascorbate (Sa) on degree of conversion (DC) and bond strength (BS) of RealSeal SE to sodium hypochlorite (NaOCl) treated root dentin. Two hundreds simulated canals were prepared and irrigated with Distilled water(DW), 1.3% NaOCl (1.3% N), 5.2% NaOCl (5.2% N), MTAD, 17% EDTA (EDTA), 10% Sa, 1.3% NaOCl/MTAD (N-M), 1.3% NaOCl/Sa/MTAD(N-Sa-M), 5.2% NaOCl/EDTA(N-E), and 5.2% NaOCl/Sa/EDTA (N-Sa-E) respectively. They were subsequently bulk filled with RealSeal SE and analyzed with micro-Raman spectroscopy and universal testing machine for DC and BS respectively. One-way ANOVA and post hoc Tukey's test showed DC of 1.3% N, 5.2% N, N-M and N-E were significantly lower (p<0.01) than other six groups. BS of DW, Sa, N-M were significantly lower than 1.3% N, 5.2% N, MTAD, EDTA, N-Sa-M and N-E (p<0.01), and group N-Sa-E achieved the highest BS among all groups (p<0.01). NaOCl negatively affected DC and BS of RealSeal SE, which could be reversed with 10% Sa.

Heat transfers to periodontal tissues and gutta-percha during thermoplasticized root canal obturation in a finite element analysis model.

OBJECTIVES: The aim of this study was to measure the temperature distributions on the periodontal ligament and apical gutta-percha during thermal obturation with different plugger activation time. STUDY DESIGN: The multirooted model of mandibular first molar development and root canal treatment were performed by finite element analysis. The apical thirds of canals were obturated by continuous-wave condensation technique, with 3 seconds and 4 seconds of activation time. The remainder was backfilled with injected gutta-percha in 2 segments (Obtura II). RESULTS: The highest temperatures on the periodontal ligament reached 46.914 degrees C and 48.887 degrees C, in the "dangerous zone" between the root canals, when activation times were 3 seconds and 4 seconds, respectively. The greatest temperature rise within the apical gutta-percha was only 0.859 degrees C. CONCLUSION: With 3 seconds of activation, the temperature elevation reached almost 47 degrees C, so one should be careful not to extend the activation time beyond 3 seconds, which is clinically difficult to control. The apical gutta-percha temperature was always below the desired level to achieve proper thermoplasticity.

Degree of conversion of a methacrylate-based endodontic sealer: a micro-Raman spectroscopic study.

INTRODUCTION: Recently, a methacrylate-based obturation system, Resilon/RealSeal SE, has been developed to replace gutta-percha and traditional sealers. As a resin-based material, degree of conversion (DC) is one of the most important characteristics. The aim of this study was to investigate the time-dependent change of DC of RealSeal SE as well as the influence of canal moisture and root canal depth on it. METHODS: DC of RealSeal SE, either self-cured or dual-cured (n = 8 in each group), was calculated according to the Raman spectra obtained at different times after mixing. Thirty extracted teeth with single canal were instrumented and divided randomly into 2 groups in terms of different canal drying methods. In the ethanol group, excess distilled water in root canal was removed with paper points followed by 95% ethanol. In the paper points group, root canals were blot-dried with paper points until the last one appeared dry. DC of RealSeal SE was calculated from serial cross sections (2, 5, and 8 mm from the apex) obtained 1 week after obturation with Resilon/RealSeal SE. RESULTS: Significant increase in DC of RealSeal SE was observed in 1 week (P < .01), with little change afterwards (P > .05). DC of sealer in ethanol group was significantly higher than in paper points group (P < .01). However, DCs of RealSeal SE at different levels of tooth sections were not significantly different (P > .05). CONCLUSIONS: Both self-cured and dual-cured RealSeal SE achieved stable DC after 1 week. Root canal moisture was a critical factor in determining DC of RealSeal SE.