Application of proanthocyanidin in the treatment and repair of deep caries / 口腔疾病防治

@#Proanthocyanidin (PA), as a kind of natural plant polyphenol, have a variety of biological functions, such as promoting remineralization, inducing collagen cross-linking, inhibiting protease activity and inhibiting bacteria. Therefore, PA could be broadly used in the clinical application of treatment and repair of deep caries in the future; for example, PA could promote dentin remineralization, improve resin-dentin bonding durability and improve the dentin acid erosion effect. This application potential of PA arises from several features, firstly, PA can not only promote dentin remineralization on its own or with other remineralizers but also exhibits antibacterial effects, which can inhibit acid production while reducing the formation of cariogenic pathogens and their biofilms. Based on the above features, PA can reduce the incidence of caries disease; thus, PA improves deep caries and long-term effects after treatment. In addition, PA added to adhesives or etch agents can improve the etching and bonding effect of dentin by inducing collagen cross-linking and inhibiting protease activity, thus achieving the ultimate goal of improving the bonding performance of deep caries. This paper summarizes recent progress of research on PA for the treatment and repair of deep caries, including the promotion of dentin remineralization and antibacterial activity as well as the improvement in dentin bonding and acid etching effect, to provide a more comprehensive reference for treating and restoring deep caries in clinical practice.

Research progress on oral characterization of Corona Virus Disease 2019 / 口腔疾病防治

@#Corona Virus Disease 2019 (Corona Virus Disease 2019,COVID-19) has become a public health emergency that has attracted global attention because of its large-scale outbreak resulting in numerous human infections and deaths. COVID-19 is a highly contagious respiratory disease caused by novel coronavirus 2019-nCoV. Due to a large number of infections and fast transmission speed, it's significant to diagnose the infected people quickly and detect the asymptomatic infected people as soon as possible. At present, the preliminary screening is judged by the clinical manifestations of the patients, mainly involving the respiratory system, but recent studies have found that the patients infected with COVID-19 have unique oral manifestations, such as taste disturbance, xerostomia, halitosis, inflammation of salivary glands, necrotizing periodontal disease and some of them are earlier than typical symptoms such as dry cough, fever, etc. Paying attention to the oral manifestations of patients can further improve the COVID-19 screening procedure. At present, symptomatic treatment is mainly used for these oral symptoms.

Biomimetic restoration and regeneration of dentin and cementum / 口腔疾病防治

@#Dental hard tissues lack the ability to self-heal. In dentin and cementum, hydroxyapatite (HA) can exist outside and/or inside collagen fibers. It is difficult to repair or regenerate HA with a highly ordered orientation in the presence of collagen fibers. At present, the biomimetic mineralization of dentin and cementum, mainly carried out by imitating its biological formation process and its physiological structure, can be divided into those originating from the fiber mineralization mechanism and those with HA as the main component. The materials used include natural materials such as demineralized dentin matrix (DDM) and calcined bovine hydroxyapatite (BHA), and synthetic materials such as polymer-induced liquid precursor (PILP) and synthetic HA. In the future, natural materials and synthetic materials should be combined for the restoration and regeneration of dentin and cementum by means of biomimetic mineralization of calcium phosphate released by remineralization solution-HA.

Inhibitory effect of silencing HMGB1 gene on growth of human epithelial ovarian cancer xenografts in nude mice / 中国肿瘤生物治疗杂志

@#[Abstract] Objective: To investigate the effect of HMGB1 gene on the growth of human epithelial ovarian cancer xenografts in nude mice, and to lay a foundation for finding new targets for the treatment of ovarian cancer. Methods: Human epithelial ovarian cancer SKOV3 cells in logarithmic growth phase were selected to establish a human epithelial ovarian cancer xenograft model in nude mice. Nude mice with successful model establishment were randomly divided into control group and HMGB1-siRNA group. On the 7th, 9th, 11th, 14th, and 16th days after cell inoculation, the same amount of saline and HMGB1-siRNA were respectively injected into two groups of mice under the armpit.After 3 weeks, the nude mice were sacrificed by cervical dislocation, the tumor tissues were separated, and the volume of the tumor was measured. The apoptosis of transplanted tumor cells was detected by Tunnel staining. The expressions of HMGB1, STAT3 and p-STAT3 were detected by Western blotting. The expression of vascular endothelial growth factorA(VEGF-A) and microvascularization were detected by immunohistochemistry. Results: Compared with the control group, the growth of tumor volume slowed down in HMGB1 siRNA group, and on the 21st day, the tumor volume of HMGB1-siRNA group was significantly smaller than that of the control group (P<0.05). HMGB1-siRNA successfully knocked down the expression of HMGB1 mRNA in transplanted tumor tissue. The apoptosis rate of tissue cells in HMGB1-siRNA group was significantly increased ([34±8]% vs [6±2]%, P=0.04), and the expressions of HMGB1 and p-STAT3 were significantly reduced (P<0.05). The expression of VEGF-Aand the number of microvessels were significantly lower than those of the control group (both P<0.05). Conclusion: Knockdown of HMGB1 gene reduces the expression of VEGF-A and microvessel formation possibly by inhibiting the HMGB1/STAT3 signaling pathway, thereby promoting the apoptosis of tumor tissues and slowing the growth of xenografts.

miR-140 inhibits PD-L1 expression to enhance sensitivity of cervical cancer HeLa and Caski cells to oxaliplatin / 中国肿瘤生物治疗杂志

@# Objective: To investigate whether miR-140 could increase the sensitivity of cervical cancer (CC) to oxaliplatin by downregulating the expression of programmed death-1 (PD-L1). Methods: qPCR was used to analyze miR-140 expression in normal human cervical cells, CC cells and oxaliplatin-resistant CC cells. Cells were transfected with miR-140 mimic, and then, the proliferation of CC cells and oxaliplatin-resistant CC cells was detected by using CCK-8 assay, and the colony formation rate of CC cells was obtained by using colony formation assay. Starbase and TargetScan were used to predict the targeted binding site of miR-140 and PD-L1, and the influence of miR-140 on the expression of PD-L1 was validated by dual luciferase reporter gene assay.Annexin V FITC/PI double staining and Wb assays were used to detect the effect of over-expression of miR-140 or both over-expression of PD-L1 and miR140 on the apoptosis, migration and expression of apoptosis-related proteins in CC cells after treatment with oxaliplatin. Moreover, transplantation tumor of CC cell lines was established in nude mice to assess the effects of miR-140 on enhancing the sensitivity of tumors to oxaliplatin. Results: The expression of miR-140 was significantly decreased in oxaliplatin-resistant CC cells (P<0.01). Over-expression of miR140 could significantly increase the sensitivity of oxaliplatin-resistant CC cells to oxaliplatin (P<0.05), and inhibit the CC cells proliferation and colony formation (P<0.01). miR-140 showed targeted binding to PD-L1 3'-UTR and inhibited its expression. Over-expression of miR-140 significantly promoted CC cell migration and apoptosis (P<0.01). However, co-transfection of PD-L1 counteracts the effects of miR-140 on cell metastasis and apoptosis (all P<0.05). In addition, xenograft tumor model in mice also verified that miR-140 could promote the sensitivity of tumors to oxaliplatin. Conclusion: miR-140 increases the sensitivity of CC to oxaliplatin through inhibition of PD-L1 expression. Therefore, up-regulation of miR-140 or down-regulation of PD-L1 in combination with oxaliplatin may be a novel strategy for the treatment of Oxaliplatin-resistant CC.

Finite element analysis of the stress distribution of two-piece post crown with different adhesives / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To establish three-dimensional finite element model of two-piece post crown to the mandibular first molar residual roots, and analyze the stress distribution characteristic to the residual roots with different adhesives, so as to get the best combination under different conditions.</p><p><b>METHODS</b>The complete mandibular first molar in vitro was selected, the crown was removed along the cemento-enamel junction, then the residual roots were scanned by CT. CT images were imported into a reverse engineering software, and the three-dimensional finite element model of the mandibular first molar residual roots was reconstructed. Titanium two-piece post crown of the mandibular first molar residual roots was produced, then was scanned by CT. The model was reconstructed and assembled by MIMICS. The stress distribution of the root canal and root section under the vertical load and lateral load with different bonding systems were analyzed.</p><p><b>RESULTS</b>Three-dimensional finite element model of two-piece post crown to the mandibular first molar residual roots was established. With the increasing of elastic modulus of the adhesives, the maximum stress within the root canal was also increasing. Elastic modulus of zinc phosphate was the biggest, so the stress within the root canal was the biggest; elastic modulus of Superbond C&B was the smallest, so the stress within the root canal was the smallest. Lateral loading stress was much larger than the vertical load. Under vertical load, the load on the root section was even with different bonding systems. Under lateral load, the maximum stress was much larger than the vertical load. The stress on the root section was minimum using zinc phosphate binder, and the stress on the root section was maximum using Superbond C&B.</p><p><b>CONCLUSION</b>In two-piece post crown restorations, there is significant difference between different adhesives on tooth protection. When the tooth structure of the root canal orifices is weak, in order to avoid the occurrence of splitting, the larger elastic modulus bonding system is the first choice, such as zinc phosphate binder. When the resistance form of the root canal orifices is good enough but the root is too weak, it is suggested that the smaller elastic modulus bonding system is the first choice, such as Superbond C&B.</p>