ABSTRACT
MicroRNAs are a large group of small, non-coding ssRNAs (miRNAs) that have an epigenetically pivotal role in gene expression and other biological processes in cells and can be regarded as capable biomarkers for the early detection and management of cancer. The aim of the present review article is to summarize the evidence for recognizing the molecular mechanism, target genes, and clinical significance of miR-647 in different cancers. Multiple studies have demonstrated that aberrant expression of miR-647 could be found in a variety of malignancies, such as bladder cancer, cervical cancer, colorectal cancer, gastric cancer, glioma, hepatocellular carcinoma, non-small cell lung cancer, ovarian cancer, and prostate cancer have reported, notably, increase or decrease in expression of miR-647 so that it can function as a tumorigenic (oncomiR) or tumor suppressor gene. MiR-647 is effective in the proliferation, migration, and invasion of cancer cells by playing a function in cell cycle pathways. MiR-647 can be a valuable potential biomarker for assessing the extent of cancer, prognosis, and response to therapy and shows great therapeutic efficacy in different solid tumors. Moreover, serum concentrations of miR-647 are directly effective in decreasing overall survival and disease progression. So, an efficient therapeutic target can be the effect on miR-647 expression by antitumor drugs.
ABSTRACT
BACKGROUND: Glass fiber posts, along with their esthetic properties, may have a better stress distribution than cast posts, Therefore, the aim of the present study was to investigate the effect of glass fiber, casting, titanium, and zirconia posts on stress distribution in maxillary central tooth treated with different amounts of ferrule using finite-element analysis. MATERIALS AND METHODS: In this experimental study, three-dimensional models of maxillary central incisors that have undergone root canal treatment were designed. Then, the models were divided into four groups according to the type of post (Ni-Cr casting, glass fiber, titanium, and zirconia) used. Zirconia monolithic crowns were used in all the four groups. Ferrule heights were repeated at 0 and 2 mm in all models. Models were entered into COMSOL Metaphysics software. Then, the force of 100 N with the angle of 135° on the palatal surface was applied to the longitudinal axis of the tooth, and the stress distribution in the models was investigated. RESULTS: Maximum stress was observed in the middle third of posts. Stress distribution in glass fiber post was better than zirconia and casting posts. Stress accumulation in models with zirconia, titanium, and casting posts was also found in the site between the middle third and coronal third, whereas in models with glass fiber post, stress accumulation was found between the crown and the cemento-enamel junction. In models without ferrule, stress accumulation was observed in one-third of the coronal, especially in glass fiber posts. CONCLUSION: The post material and ferrule height affected stress concentration. The stress in the cervical area of the dentin was more for glass fiber post when compared to other posts. The use of glass fiber post in teeth with no ferrule results in lower stress along the post, but greater stress in the simulated tooth region.
