Extrapolating neurogenesis of mesenchymal stem/stromal cells on electroactive and electroconductive scaffolds to dental and oral-derived stem cells / 国际口腔科学杂志·英文版

The high neurogenic potential of dental and oral-derived stem cells due to their embryonic neural crest origin, coupled with their ready accessibility and easy isolation from clinical waste, make these ideal cell sources for neuroregeneration therapy. Nevertheless, these cells also have high propensity to differentiate into the osteo-odontogenic lineage. One strategy to enhance neurogenesis of these cells may be to recapitulate the natural physiological electrical microenvironment of neural tissues via electroactive or electroconductive tissue engineering scaffolds. Nevertheless, to date, there had been hardly any such studies on these cells. Most relevant scientific information comes from neurogenesis of other mesenchymal stem/stromal cell lineages (particularly bone marrow and adipose tissue) cultured on electroactive and electroconductive scaffolds, which will therefore be the focus of this review. Although there are larger number of similar studies on neural cell lines (i.e. PC12), neural stem/progenitor cells, and pluripotent stem cells, the scientific data from such studies are much less relevant and less translatable to dental and oral-derived stem cells, which are of the mesenchymal lineage. Much extrapolation work is needed to validate that electroactive and electroconductive scaffolds can indeed promote neurogenesis of dental and oral-derived stem cells, which would thus facilitate clinical applications in neuroregeneration therapy.

External cervical resorption-a review of pathogenesis and potential predisposing factors / 国际口腔科学杂志·英文版

External cervical resorption (ECR) refers to a pathological state in which resorption tissues penetrate into the dentin at the cervical aspect of the root. Despite being latent in its initial phase, ECR could cause severe damage to mineralized dental tissue and even involve the pulp if not given timely diagnosis and treatment. Nevertheless, the etiology of ECR is still poorly understood, which adds to the difficulty in early diagnosis. ECR has received growing attention in recent years due to the increasing number of clinical cases. Several potential predisposing factors have been recognized in cross-sectional studies as well as case reports. In the meantime, studies on histopathology and pathogenesis have shed light on possible mechanisms of ECR. This review aims to summarize the latest findings in the pathogenesis and potential predisposing factors of ECR, so as to provide pragmatic reference for clinical practice.

Mutation in ε-Sarcoglycan Induces a Myoclonus-Dystonia Syndrome-Like Movement Disorder in Mice / 神经科学通报·英文版

Myoclonus dystonia syndrome (MDS) is an inherited movement disorder, and most MDS-related mutations have so far been found in the ε-sarcoglycan (SGCE) coding gene. By generating SGCE-knockout (KO) and human 237 C > T mutation knock-in (KI) mice, we showed here that both KO and KI mice exerted typical movement defects similar to those of MDS patients. SGCE promoted filopodia development in vitro and inhibited excitatory synapse formation both in vivo and in vitro. Loss of function of SGCE leading to excessive excitatory synapses that may ultimately contribute to MDS pathology. Indeed, using a zebrafish MDS model, we found that among 1700 screened chemical compounds, Vigabatrin was the most potent in readily reversing MDS symptoms of mouse disease models. Our study strengthens the notion that mutations of SGCE lead to MDS and most likely, SGCE functions to brake synaptogenesis in the CNS.

Building public service platform for clinical research to facilitate the management of medical research / 中华医学科研管理杂志

Objective:Through the construction of public service platform for clinical research of oral diseases, to facilitate more efficient and orderly development of clinical research and related management.Methods:The construction of clinical platform for oral diseases includes data sharing platform, scale system of various disciplines, specialized terminology system, electronic medical record access, clinical research project management system, etc.Results:The established platform can assist physicians in standardizing clinical research in their daily diagnosis and treatment work through a unified terminology scale system; simplify the data integration process through seamless connection of medical data and research data; and realize the whole process management of research through the application of clinical research project management system.Conclusions:The establishment and operation of the platform has significantly increased the inclusion of clinical research samples, promoted the efficient and orderly development of clinical research related work, and significantly improved the management of clinical research.

Development of human embryonic stem cell platforms for human health-safety evaluation / 北京大学学报(医学版)

SUMMARY Thehumanembryonicstemcells(hESCs)serveasaself-renewable,genetically-healthy, pluripotent and single source of all body cells,tissues and organs.Therefore,it is considered as the good standard for all human stem cells by US,Europe and international authorities.In this study,the standard and healthy human mesenchymal progenitors,ligament tissues,cardiomyocytes,keratinocytes,primary neurons,fibroblasts,and salivary serous cells were differentiated from hESCs.The human cellular health-safety of NaF,retinoic acid,5-fluorouracil,dexamethasone,penicillin G,adriamycin,lead ace-tate PbAc,bisphenol A-biglycidyl methacrylate (Bis-GMA)were evaluated selectively on the standar-dized platforms of hESCs,hESCs-derived cardiomyocytes,keratinocytes,primary neurons,and fibro-blasts.The evaluations were compared with those on the currently most adopted cellular platforms.Parti-cularly,the sensitivity difference of PM2.5 toxicity on standardized and healthy hESCs derived fibroblasts, currently adopted immortalized human bronchial epithelial cells Beas-2B and human umbilical vein endo-thelial cells (HUVECs)were evaluated.The results showed that the standardized hESCs cellular plat-forms provided more sensitivity and accuracy for human cellular health-safety evaluation.

Study on interface compatibility and fracture resistance of polyglycidyl methacrylate pre-impregnated quartz fiber reinforced polymethyl methacrylate denture base resin / 北京大学学报(医学版)

Objective: To explore the reinforcement of polyglycidyl methacrylate ( PGMA ) pre-impregnated quartz fiber mesh in denture base materials by investigation of interface compatibility and fracture resistance .Methods: 1-layer, 2-layer, 3-layer PGMA pre-impregnated quartz fiber meshes , electrolyzed cobalt-chromium alloy mesh and cobalt-chromium alloy mesh conditioned by metal primer were integrated in polymethyl methacrylate ( PMMA) resin by sandwich embedding method .Block sam-ples of 5 groups were prepared (40 mm ×15 mm ×2 mm).Fracture resistance was determined in a 3-point bending test at 2 mm/min.Scanning electron microscope (SEM), micrographs were taken from the fractured surfaces to analyze the bonding interface compatibility .Results: The group of 3-layer PGMA pre-impregnated quartz fiber mesh presented the highest elastic modulus of 6 406 MPa and flexural strength of 227 MPa among the five groups , while the 1-layer and 2-layer expressed the similar elastic modulus and flexural strength to the pure PMMA group .The metal groups demonstrated better mechanical properties, while the metal surface conditioner played much better .The metal surface conditioner pre-impregnated cobalt-chromium alloy and PGMA pre-impregnated quartz fiber mesh showed compatible in-terface with PMMA.Conclusion:The mechanical properties were improved by the increasing of the fiber by adding the more meshed .Although the benign interface did help the compatibility , the quantity of the fibers played an important role in the strength .

Investigation on the short-term clinical application of two types of glass fiber posts / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The clinical results of restoring defective teeth with two types of glass fiber prothetic systems is investigated to acquire clinical experience for further application of glass fiber posts with independent intellectual property rights.</p><p><b>METHODS</b>A total of 120 out-patients with restored defective teeth were selected from the Department of Stomatology, Beijing Xuanwu Hospital of Traditional Chinese Medicine and Peking University School and Hospital of Stomatology and randomly divided into two groups. OUYA FIBER posts and Tenax Fiber White posts were used to restore defective teeth in the experimental group and the control group, respectively. Clinical evaluation was conducted one week and three months post-restoration.</p><p><b>RESULTS</b>Both clinical satisfactory rates of OUYA FIBER posts and Tenax Fiber White posts were higher than 98% one week post-restoration and higher than 96% three months post-restoration. No significant differences were observed between the clinical results of restoring defective teeth with the two types of fiber posts. Throughout the healing process, no root canal fracture or marginal staining were observed.</p><p><b>CONCLUSION</b>OUYA FIBER post and Tenax Fiber White post showed similar clinical outcomes during the period of observation in this study. However, the long-term effects should be observed in future studies.</p>

Effect of water storage on the flexural properties of three dual-cure core buildup composite resins / 中国组织工程研究

BACKGROUND:Hydrothermal condition of oral environment has an effect on the mechanical properties of dental core materials. OBJECTIVE:To evaluate effect of water storage on the weight change rates and flexural properties of three dual-cure core buildup composite resins. METHODS: Rectangular specimens (25 mm×2 mm×2 mm) were prepared from three dual-cure core buildup composite resins (LuxaCore Smartmix Dual, Para core and Clearfil DC Core). Specimens were stored in distiled water at 37℃ for 0, 1 day, 1, 2, 3 weeks and 1 month, respectively, weighted and then subjected to three-point bending test in a universal testing machine. RESULTS AND CONCLUSION: Weight change rates of the three composite resins increased with immersion time; at the same immersion time, weight change rates of three composite resins ranked as the folowing order: LuxaCore Smartmix Dual > ParaCore > Clearfil DC Core. The flexural strength of LuxaCore Smartmix Dual decreased with immersion time. The flexural strength of ParaCore showed no significant change during 3 weeks immersion (P > 0.05), while it showed a significant decreasing after 1 month immersion (P 0.05). The flexural modulus of LuxaCore Smartmix Dual showed a decreased trend in the whole immersion process, but it showed that there was no significant change during the first 2 weeks(P > 0.05), while a significant decrease occurred after 3 weeks and 1 month (P 0.05); the flexural properties of three composite resins showed a fluctuant decreased trend along with weight changes increased. To sum up, Clearfil DC Core showed the best water resistance among three composite resins.

Biocompatibility of electro-spinning beta-tricalcium phosphate/gelatin guided tissue regeneration menbrene versus polylactic acid and poly(lactide-co-glycolide) membrane / 中国组织工程研究

BACKGROUND: In the past, guided tissue regeneration materials were produced by 13-tricalcium phosphate (β-TCP) and gelatin (Gel), but the production of fiber membrane by electro-spinning technique was reported less.OBJECTIVE: To prepare a new kind of Gel with β-TCP hybrid nanofibrous membrane and testing its biocompatibility compared with polylactic acid (PLLA) and poly(lactide-co-glycolide) (PLGA) membrane.METHODS: The β-TCP/Gel guided tissue regeneration membrane was made by electro-spinning technique.Scanning electron microscopy (SEM) was employed to observe membrane surface.MTT test was performed to compare toxicity among β-TCP/Gel,PLLA, and PLGA membranes.RESULTS AND CONCLUSION: The β-TCP/Gel membrane was porous, and β-TCP granules were nodosity-adhered on surface of Gel.The average diameter of fiber was 500-600 nm.The distribution of fiber ranged from 200 to 500 nm.There was no significant difference in toxicity among PLLA, PLGA, and negative control group (P > 0.05).The results suggested that the β-TCP /Gel membrane was low cytotoxicity and suitable for tissue engineering.It would be a promising material for periodontal tissue regeneration.

The effect of simulate intraoral sandblasting on the band strength between enamel and composite resin / 北京大学学报(医学版)

Objective: To study whether the bond strength between enamel and composite resin could be enhanced by intraoral sand abrasive. Methods: Ten human maxillary first incisior teeth were divided into 2 groups The experimental group was sandblasted with 30 ?m Al 2O 3 (CoJet Sand, pressure 300 kPa) from a distance of 5 mm for 5 seconds, and the control group were not sandblasted. The Herculite composite resin composite cylinders were bonded with Coltene system. Bonded specimens were stored in 37 ℃ distilled water for 24 h, then were subjected to shear force in a testing machine Stress at failure was calculated in Mpa, and mode of failure was recorded. The Student t test was applied to the data. Results: The shear bond strength of experimental groups was (33.0?1.8) MPa , and that of control groups was (26.7?5.2) MPa ,there was significant difference between these two groups. All the adhesive failures happened at the enamel composite resin interface , except that cohesive failure happened in one sandblasted specimen. Conclusion: Intraoral sandblasting could significantly enhance the shear bond strength between enamel and composite resin.

The influence of autoclave sterilization on elastic module and flexural strength of five types of posts / 西安交通大学学报(医学版)

Objective To research the influence of autoclave sterilization on elastic module and flexural strength of five types of posts.Methods Shidelong carbon,glass and quartz fiber post,tenax glass fiber post and Anthogyr titanium post were chosen,and all the samples were divided into two groups which included five subgroups according to the model of posts,each subgroup including six samples.Experimental groups were autoclave sterilized(50 min at 134℃ and 2.2MPa),While the control groups were not.With three point loading system,elastic module and flexural strength of all the samples were measured.Results were statistically analyzed to find the difference between them.Results There was no statistical difference between Shidelong carbon,glass,quartz fiber post and Tenax glass fiber post in elastic module and flexural strength in both experimental group and control group,while Anthogyr titanium post gained the highest elastic module and flexural strength.Paired-samples t test also showed there was no statistical difference between experimental group and control group in elastic module and flexural strength.Conclusion Fiber posts perfectly meet the need of clinical use on flexural strength.Furthermore,with elastic module similar to dentin and much lower than metal posts,fiber posts will help to protect the remaining tooth structure from fracture.Autoclave sterilization has a little influence on elastic module and flexural strength of posts,which allows practitioners to systematically sterilize the posts in clinic.