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 .

OBJECTIVEThe 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.

METHODSA 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.

RESULTSBoth 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.

CONCLUSIONOUYA 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.

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.

AIM: To study I_ to channel function in severe burn and its contribution to cardiac dysfunction induced by severe burn. METHODS: CHO-K1 cells were transfected with human Kv4.3, the major subunit of human I_ to channel. The expressed Kv4.3 channels were recorded by whole-cell patch clamp and the effects of rat burn serum on Kv4.3 current densities and kinetics were observed. RESULTS: Kv4.3 channels expressed in CHO-K1 cells were endowed with the characterization of fast activation and inactivation, which was quite similar to that of native I_ to channels in cardiomyocytes. Rat's burn serum at the concentration of 2% decreased the current density significantly. At +40 mV, the current density in control group was (67.6?15.1) pA/pF, in contrast to (32.3?9.7)pA/pF in burn serum-treated group (P

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). There was no significant change on the flexural strength of Clearfil DC Core in the whole immersion process(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). Compared with original specimens, the flexural modulus of ParaCore and Clearfil DC Core showed a decreased trend, but this change was not significant (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.

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.

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.

Circadian rhythms are self-sustaining oscillations within biological systems that play key roles in a diverse multitude of physiological processes.The circadian clock mechanisms in brain and peripheral tissues can oscillate independently or be synchronized/disrupted by external stimuli.Dental enamel is a type of mineralized tissue that forms the exterior surface of the tooth crown.Incremental Retzius lines are readily observable microstructures of mature tooth enamel that indicate the regulation of amelogenesis by circadian rhythms.Teeth enamel is formed by enamel-forming cells known as ameloblasts,which are regulated and orchestrated by the circadian clock during amelogenesis.This review will first examine the key roles of the circadian clock in regulating ameloblasts and amelogenesis.Several physiological processes are involved,including gene expression,cell morphology,metabolic changes,matrix deposition,ion transportation,and mineralization.Next,the potential detrimental effects of circadian rhythm disruption on enamel formation are discussed.Circadian rhythm disruption can directly lead to Enamel Hypoplasia,which might also be a potential causative mechanism of amelogenesis imperfecta.Finally,future research trajectory in this field is extrapolated.It is hoped that this review will inspire more intensive research efforts and provide relevant cues in formulating novel therapeutic strategies for preventing tooth enamel developmental abnormalities.

Objective 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. Methods 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. Results 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. Conclusion 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.

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.