Cancer stem cells and oral cancer: insights into molecular mechanisms and therapeutic approaches.

Cancer stem cells (CSCs) have been identified as a little population of cancer cells, which have features as the same as the cells normal stem cells. There is enough knowledge of the CSCs responsibility for metastasis, medicine resistance, and cancer outbreak. Therefore, CSCs control possibly provides an efficient treatment intervention inhibiting tumor growth and invasion. In spite of the significance of targeting CSCs in treating cancer, few study comprehensively explored the nature of oral CSCs. It has been showed that oral CSCs are able to contribute to oral cancer progression though activation/inhibition a sequences of cellular and molecular pathways (microRNA network, histone modifications and calcium regulation). Hence, more understanding about the properties of oral cancers and their behaviors will help us to develop new therapeutic platforms. Head and neck CSCs remain a viable and intriguing option for targeted therapy. Multiple investigations suggested the major contribution of the CSCs to the metastasis, tumorigenesis, and resistance to the new therapeutic regimes. Therefore, experts in the field are examining the encouraging targeted therapeutic choices. In spite of the advancements, there are not enough information in this area and thus a magic bullet for targeting and eliminating the CSCs deviated us. Hence, additional investigations on the combined therapies against the head and neck CSCs could offer considerable achievements. The present research is a review of the recent information on oral CSCs, and focused on current advancements in new signaling pathways contributed to their stemness regulation. Moreover, we highlighted various therapeutic approaches against oral CSCs.

Teeth-derived stem cells: A source for cell therapy.

Cell therapy is one of the important therapeutic approaches in the treatment of many diseases such as cancer, degenerative diseases, and cardiovascular diseases. Among various cell types, which could be used as cell therapies, stem cell therapy has emerged as powerful tools in the treatment of several diseases. Multipotent stem cells are one of the main classes of stem cells that could originate from different parts of the body such as bone marrow, adipose, placenta, and tooth. Among several types of multipotent stem cells, tooth-derived stem cells (TDSCs) are associated with special properties such as accessible, easy isolation, and low invasive, which have introduced them as a good source for using in the treatment of several diseases such as neural injuries, liver fibrosis, and Cohrn's disease. Here, we provided an overview of TDSCs particular stem cells from human exfoliated deciduous teeth and clinical application of them. Moreover, we highlighted molecular mechanisms involved in the regulation of dental stem cells fate.

State of the art in microRNA as diagnostic and therapeutic biomarkers in chronic lymphocytic leukemia.

Early diagnostic is one of the most important steps in cancer therapy which helps to design and choose a better therapeutic approach. The finding of biomarkers in various levels including genomics, transcriptomics, and proteomics levels could provide better treatment for various cancers such as chronic lymphocytic leukemia (CLL). The CLL is the one of main lymphoid malignancies which is specified by aggregation of mature B lymphocytes. Among different biomarkers (e.g., CD38, chromosomes abnormalities, ZAP-70, TP53, and microRNA [miRNA]), miRNAs have appeared as new diagnostic and therapeutic biomarkers in patients with the CLL disease. Multiple lines of evidence indicated that deregulation of miRNAs could be associated with pathological events which are present in the CLL. These molecules have an effect on a variety of targets such as Bcl2, c-fos, c-Myc, TP53, TCL1, and STAT3 which play critical roles in the CLL pathogenesis. It has been shown that expression of miRNAs could lead to the activation of B cells and B cell antigen receptor (BCR). Moreover, exosomes containing miRNAs are one of the other molecules which could contribute to BCR stimulation and progression of CLL cells. Hence, miRNAs and exosomes released from CLL cells could be used as potential diagnostic and therapeutic biomarkers for CLL. This critical review focuses on a very important aspect of CLL based on biomarker discovery covers the pros and cons of using miRNAs as important diagnostics and therapeutics biomarkers for this deadly disease.

Oral tumors in children: Diagnosis and management.

Oral tumors are one of important tumors which could be associated with serious problems in infant and children. It has been showed that a variety of cellular and molecular pathways including genetics and epigenetics mechanisms (eg, chromosomal alterations, and microRNA) involved in pathogenesis events present in oral tumors. Identification of these pathways could contribute to better treatment of oral tumor patients. Early detection is one of key steps in management of oral tumors which could contribute to improve clinical outcomes and better treatment of infant with oral tumors. Despite of easy accession of the oral cavity, oral tumors (malign/benign) are diagnosed in advance stages. Therefore, these tumors indicate a poor survival rate. It has been showed that various approaches including imaging techniques, chemical, genetics, and epigenetic biomarkers could have critical roles in early detection of oral tumors. Treatment of oral tumors is associated with employing of various therapeutic approaches including surgery, chemotherapy, and radiation. Data on effective diagnostic platforms and therapeutic approaches for oral tumors in children and infant are rare. We offer that a variety of biomarkers such as microRNAs which could be used for oral tumors in adults may be good candidates for early detection of oral tumors in children. Here, we summarized various aspects of oral tumors in children such as molecular pathways, diagnosis, and management of them.

Etiological Factors Involved in Molar-Incisor Hypomineralization in 7 to 12-Year-Old Children in Tehran.

Objectives: Molar-incisor hypomineralization (MIH) lesions are common in children. The prevalence of MIH is variable in different communities. However, information regarding the prevalence of MIH in the Iranian population is limited. This study sought to assess the prevalence and etiological factors of MIH in 7-12-year-old children in Tehran. Materials and Methods: This descriptive, cross-sectional study evaluated 1028 elementary students between 7-12 years, selected from different districts of Tehran in 2017. The frequency of MIH in the maxillary and mandibular molars and incisors was determined by clinical examination. In order to assess the role of different factors in the development of MIH, a questionnaire was filled out by the mothers regarding problems during their pregnancy, medical history of children, and age of occurrence of systemic conditions (if any). The effect of different factors on the development of MIH was analyzed by the logistic regression test. Results: The prevalence of MIH was found to be 25.6%. The delivery condition of the mother (P<0.001), history of urinary tract infection (P<0.011), history of chickenpox (P<0.018), and frequent use of amoxicillin during childhood (P<0.041) significantly affected the occurrence of MIH. The most commonly involved teeth were the mandibular left first molars. Conclusion: The prevalence of MIH in our study population was within the range reported in the literature. Considering the relatively high prevalence of MIH in 7-12-year-old children, pediatric dentists should pay special attention to treatment of MIH.

Comparative evaluation of the effects of different methods of post space preparation in primary anterior teeth on the fracture resistance of tooth restorations.

Background. Severely damaged teeth do not have adequate structure to support the composite crown; therefore, use of the canal space has been suggested to increase retention. Furthermore, the effect of post space irrigation protocols on the fracture resistance of the primary anterior teeth has not definitely been studied in postoperative modalities. This study compared the fracture resistance of restorations of primary anterior teeth following irrigation of the post space with sodium hypochlorite and chlorhexidine with and without application of burs. Methods. Ninety-four extracted primary anterior teeth were selected. Root canal treatments were carried out, 4 mm of the post space was left empty and 1 mm was regarded as a bed. The post space was prepared with and without a bur and the irrigation procedures were carried out with 0.2% chlorhexidine and 2.5% sodium hypochlorite solutions. Composite posts were inserted into the canals and the crowns were restored. Following composite etching and light-curing, the fracture resistance of the restored teeth was determined by a universal testing machine. Results. In the sodium hypochlorite group, fracture resistance of the teeth was 376.8±107.29 N and 475.5±186.89 N without and with bur preparation, respectively. For chlorhexidine protocol, the values were 370.88±175.46 N and 430.85±178.22 N without and with bur preparation, respectively. The effect of irrigating material was not significant; however, the bur and irrigating preparation significantly increased the fracture resistance of the restored teeth (P=0.02). Conclusion. Post space irrigation with 0.2% chlorhexidine or 2.5% sodium hypochlorite did not significantly affect the fracture resistance of primary anterior teeth in the post treatment modality.