Upregulation of a potential prognostic biomarker, miR-155, enhances cell proliferation in patients with oral squamous cell carcinoma.

OBJECTIVE: We sought to investigate the role and diagnostic value of microRNA 155 (miR-155) in OSCC patients. STUDY DESIGN: Using real-time quantitative polymerase chain reaction analysis, miR-155 expression levels were assessed in OSCC cell lines and a cancerous HB cell line. The correlation between miR-155 expression level and clinical parameters was analyzed in 46 patients with OSCC. In addition, the effects of miR-155 on OSCC cell proliferation were evaluated by modulating its expression using an miR-155 mimic and antisense miR-155. RESULTS: Significant upregulation of miR-155 was found in OSCC cell lines and in tissues of patients with OSCC. The receiver operator characteristic analysis indicated fair-to-good predictability. Overexpression of miR-155 correlated with the histologic grade (P = .033), and the upregulation of miR-155 enhanced OSCC cell proliferation. CONCLUSIONS: In OSSC, upregulation of miR-155 correlated with the histologic grade and can be used as a potential prognostic biomarker.

Optimum post and tooth root diameters for a cast post-core system.

PURPOSE: To investigate the optimum diameter for the tapered post of a cast alloy post-core system relative to the root diameter, when measured at the root face, that is required to minimize both post and root failures. METHODS: 32 extracted maxillary central incisor teeth were each decoronated perpendicular to the long axis at a point 2.0 mm occlusal to the labial cemento-enamel junction. Following endodontic canal obturation, the teeth were assigned randomly to four equal groups for different diameter tapered post space preparations. Then 1.10, 1.50, 1.70, and 2.00 mm diameter cast Ni-Cr alloy post-cores and complete crowns without ferrules were fabricated. Each root was embedded in a large gypsum stone block and the crown loaded palatally at 135 degrees from the long axis in a universal testing machine at a crosshead speed of 1.0 mm/minute until failure. Results were analyzed using one-way ANOVA with Tukey-Kramer post hoc tests, and Fisher's exact test, with alpha = 0.05 for statistical significance. RESULTS: Mean failure resistance loads were: 0.60, 0.91, 1.00, and 1.38 kN (P < 0.001). All of the 1.10 mm posts failed, without any root fractures. Conversely, none of the 2.00 mm posts failed, but all of the roots fractured. The optimum post to root diameter ratio to minimize failures was approximately 1:4.