检索结果-南通市图书馆

Influence of EDTA on demineralization Rate of Dentine:Calcification Treatment in Root Canal Therapy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2014年第7期30卷 692-698页

作者： Yang Ji Min He Shijie Chang Xiaodong Zhang Huazhe Yang Department of Stomatology General Hospital of Shenyang Military Area Command College of Biomedical Engineering Chongqing Medical University College of Basic Medical Science China Medical University

The aim of this study was to investigate the influence of ethylenediaminetetraacetic acid （EDTA） irrigation on demineralization rate of dentine located in the apical third of root canal walls. Teeth were divided into A and B two groups. In group A, all of the teeth was irrigated with EDTA and NaOCI （sodium hypochlorite）, followed by cutting the apical third into slices longitudinally to examine the influence of EDTA on different portions of apical third of root canal. In group B, the apical third of a tooth was firstly cut into slices longitudinally, followed by coating the root canal walls with EDTA to in-situ observe the demineralization of dentine with different time. It was found that the influence of EDTA on root-canal was gradually increased from the apical to the upper end of the apical third for group A. In addition, the demineralization rate of dentine was remarkable in the first 25 min for group B. The diffusion of EDTA into root dentine would lead to potential damage to the dentine. Furthermore, demineralization rate curve was calculated.

关键词： Ethylenediaminetetraacetic acid （EDTA） Root canal demineralization Dentine

A comparative study on demineralization of coals by acid-washing and solvent-extraction methods for low temperature catalytic coal gasification application

在线全文

学校读者我要写书评

暂无评论

Carbon Resources Conversion 2019年第3期2卷 175-181页

作者： Atul Sharma Akimitsu Matsumura Research Institute of Energy Frontier Non-conventional Carbon Resources GroupNational Institute of Advanced Industrial Science&Technology16-1OnogawaTsukubaJapan

Catalytic coal gasification is an efficient way to achieve high conversion rates at low temperatures.Catalyst loss due to the reaction between the inherent mineral matter in the coal and the catalyst is a major hurdle for its practical application.The problem may be overcome by removing the mineral matter from the coal before use.Two demineralizing approaches,acid-washing and solvent-extraction methods are investigated for demineralizing the coals.Elemental analysis,XRD analysis,NMR analysis,and N_(2)adsorption analysis were made to compare the demineralization efficiency,crystallographic carbon microstructure,chemical structure,and micro-porosity,respectively.Solvent-extraction method was found be more efficient for demineralization.Difference was observed in the chemical structure and micro-porosity while crystallographic carbon-microstructure was found to be similar.Non-catalytic and catalytic gasification reactivity of the chars obtained by the two methods was compared.Gas composition and gas evolution profiles were also obtained and found to be influenced by the degree of demineralization.

关键词： Coal demineralization Acid washing Solvent extraction Catalytic gasification

Clinical assessment of demineralization and remineralization surrounding orthodontic brackets with FluoreCam

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Biomedicine 2017年第4期7卷 373-377页

作者： Bora Korkut Duygu Korkut Funda Yanikoglu Dilek Tagtekin Department of Restorative Dentistry Faculty of DentistryMarmara UniversityHealth Science Campus Department of Orthodontics Faculty of DentistryMarmara UniversityHealth Science Campus

Objective: To determine quantitatively the amount of demineralization and the ability of commercially available products and an experimental cream to inhibit or reverse orthodontic related demineralization.Methods: A total of 20 patients who were 25–35 years old and having orthodontic treatment for 6–8 months were chosen.Caries risk assessments were done for each patient and ones with "moderate risk" were included.Patients with fixed orthodontic appliances were divided into 4 groups(5 patients each) including one control and 3 study groups.All patients used same toothpaste 2 times a day during the 3 weeks study period.Additional to the toothpaste first study group used MI Paste Plus(GC, Tokyo, Japan), second study group used Remin Pro(Voco, Cuxhaven, Germany) and third group used an experimental remineralizing cream per day for 3 weeks.Maxillary central and lateral incisors of each patient were examined by FluoreCam(Daraza Therametric Technologies, USA) device.The examinations were performed at baseline and at the end of 1st, 2nd and 3rd weeks.Results: According to the FluoreCam measurements the control group showed significant amount of demineralization at the end of 3 weeks, moreover the amount of demineralization has gradually increased in time.At the end of the study all 3 study groups showed significant amount of remineralization and the amount of remineralization for all the 3 study groups has gradually increased in time.However the amount of remineralization for 3rd study group was lesser than the 1st and 2nd study groups.The remineralization amounts for the 1st and 2 nd study groups were determined to be identical.Conclusions: This study demonstrated that demineralization is measurable around orthodontic brackets and the demineralization can be completely inhibited and/or reversed by the use of commercially available remineralization products.

关键词： demineralization Remineralization FluoreCam Orthodontic brackets MI Paste Plus Remin Pro

Longitudinal evaluation of mineral loss at the earliest stage of enamel demineralization using micro-computed tomography

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Health 2012年第6期4卷 334-340页

作者： Koji Watanabe Tomomi Nakamura Takashi Ogihara Yoshiyuki Ochiai Shigeru Watanabe Division of Pediatric Dentistry Department of Human Development & Fostering School of Dentistry Meikai University Sakado Japan k-watanabe@dent.meikai.ac.jp

As the prevalence of dental caries decreases, the diagnosis and treatment of initial mineral loss resulting in white spot lesions have been getting more and more important. Since dental CT provides computed tomography images of a tooth with radiation exposure similar to panoramic radiography, it will become possible in the near future to evaluate the enamel mineral density using CT in the same way as measurement of the bone mineral density. Such computed tomography images enable dentists to perform longitudinal, three-dimensional, and precise evaluation of the enamel mineral density before a demineralized lesion becomes detectable by any other traditional means. Despite their advantage, there are not enough reports on evalu- ation of the enamel mineral density using CT. This study evaluated the serial changes in mineral density in the earliest stage of enamel demineralization. Eight bovine enamel specimens were coated with nail varnish. On each specimen, 4 square windows measuring 1 mm2 were created. The specimens were incubated in lactic acid solution at 38?C. During incubation, the windows were covered by nail varnish one by one at 30, 60, and 90 minutes, respectively. At 120 minutes, the specimens were removed from the solution. After the nail varnish was removed, X-ray microradiography was performed using SKYSCAN1172 at settings of 100 kV and 100 μA. The mean Hounsfield unit values (HUV) of enamel in a non-window area and those in the window areas were calculated every 180 μm over a depth of 0 - 900 μm and analyzed by two-way ANOVA. Data were affected by the incubation time and depth from the enamel surface, and there was not interaction between the two factors. Considering the incubation time, HUV of the whole measured enamel (0 - 900 μm) in the non-window group was significantly higher than that of the other incubated groups. Considering the depth, HUV was decreased at 721 - 900 μm compared with that at 0 - 180 μm in the 30-minute-incubated group, and the decrease spread to 361 - 900 μm in the 60- and 90- m

关键词： Mineral Density Micro-CT demineralization Bovine Enamel Over Time Eval-uation

Effect of Galla chinensis on the In Vitro Remineralization of Advanced Enamel Lesions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Oral Science 2010年第1期2卷 15-20页

作者： Jacob M.ten Cate Department of Cariology EndodontologyPedodontologyAcademic Centre for Dentistry Amsterdam (ACTA)

Aim The effect of Galla chinensis on de-/re-mineralization of advanced enamel lesions was investigated by using micro-CT in a prolonged in vitro experiment. Methodology Baseline mineral contents of sound enamels were first analyzed. Then lesions were produced in an acidic buffer solution （2.2 mmol.L-1 Ca（NO3）2, 2.2 mmol-L1 KH2PO4, and pH=4.5） for 21 days, with thrice daily three-minute treatments, divided into four groups： Group A, 4 000 ppm crude aqueous extract of Galla chinensis （GCE）; Group B, 4 000 ppm gallic acid; Group C, 1 000 ppm F aq. （as NaF, positive control）; Group D, deionized water （negative control）. Next, the blocks were immersed in a remineralization solution （1.5 mmol.Lz CaC12, 0.9 mmol.L1 KH2PO4, 0.1 ppm F, and pH=7,0） for 200 days. Mineral loss （ML） in each region of interest （ROI） and integrated mineral loss （IML） of the lesions were calculated （comparing with baseline mineral content of sound enamel） at different time points. Results After 21 days demineralization, fluoride treatment showed a statistically significant demineralization-inhibiting effect among the four groups, and after 200 days of remineralization, mineral content recovery was ordered （lowest to highest） as A=C〈B〈D. Conclusion GCE could slow down the remineralization of enamel in the surface layer and thereby facilitate ion transport into the lesion body. The mechanism of Galla chinensis in enhancing the remineralization of dental caries is different from fluoride.

关键词： demineralization remineralization advanced enamel lesion Galla chinensis

Oral health in China: from vision to action

在线全文

学校读者我要写书评

暂无评论

International Journal of Oral Science 2018年第1期10卷 1-6页

作者： Xuedong Zhou Xin Xu Jiyao Li Deyu Hu Tao Hu Wei Yin Yujiang Fan Xingdong Zhang State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Operative Dentistry and Endodontics West China Hospital of StomatologySichuan University State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Preventive Dentistry West China Hospital of StomatologySichuan University National Engineering Research Center for Biomaterials Sichuan University

Chinese president Xi Jinping made clear at the National Health and Wellness Conference that health is the prerequisite for people’s all-around development and a precondition for the sustainable development of China. Oral health is an indispensable component of overall health in humans. However, the long neglect of oral health in overall health agendas has made oral diseases an increasing concern. With this perspective, we described the global challenges of oral diseases, with an emphasis on the challenges faced by China. We also described and analyzed the recently released health policies of the Chinese government, which aim to guide midterm and long-term oral health promotion in China. More importantly, we called for specific actions to fulfill the larger goal of oral health for the nation. The implementation of primordial prevention efforts against oral diseases, the integration of oral health into the promotion of overall health, and the management of oral diseases in conjunction with other chronic non-communicable diseases with shared risk factors were highly recommended. In addition, we suggested the reform of standard clinical residency training, the development of domestic manufacturing of dental equipment and materials, the revitalization traditional Chinese medicine for the prevention and treatment of oral diseases, and integration of oral health promotion into the Belt and Road Initiative. We look forward to seeing a joint effort from all aspects of the society to fulfill the goal of Healthy China 2030 and ensure the oral health of the nation.

关键词： GALLA-CHINENSIS EXTRACT NIDUS-VESPAE EXTRACT CHEMICAL-FRACTIONS GLOBAL BURDEN RISK-FACTOR PERIODONTAL-DISEASE ALZHEIMERS-DISEASE COLORECTAL-CANCER demineralization REMINERALIZATION

Biofilm three-dimensional architecture influences in situ pH distribution pattern on the human enamel surface

在线全文

学校读者我要写书评

暂无评论

International Journal of Oral Science 2017年第2期9卷 74-79页

作者： Jin Xiao Anderson T Hara Dongyeop Kim Domenick T Zero Hyun Koo Geelsu Hwang Eastman Institute for Oral Health University of Rochester Medical Center Department of Cariology Operative Dentistry and Dental Public HealthOral Health Research InstituteIndiana University School of Dentistry Biofilm Research Laboratories Levy Center for Oral HealthDepartment of Orthodontics and Divisions of Pediatric Dentistry & Community Oral HealthSchool of Dental MedicineUniversity of Pennsylvania

To investigate how the biofilm three-dimensional(3D) architecture influences in situ pH distribution patterns on the enamel surface. Biofilms were formed on human tooth enamel in the presence of 1% sucrose or 0.5% glucose plus 0.5% fructose. At specific time points, biofilms were exposed to a neutral pH buffer to mimic the buffering of saliva and subsequently pulsed with 1% glucose to induce re-acidification. Simultaneous 3D pH mapping and architecture of intact biofilms was performed using two-photon confocal microscopy. The enamel surface and mineral content characteristics were examined successively via optical profilometry and microradiography analyses. Sucrose-mediated biofilm formation created spatial heterogeneities manifested by complex networks of bacterial clusters(microcolonies). Acidic regions(pHdemineralization(white spots),rougher surface, deeper lesion and more mineral loss appeared to be associated with the localization of these bacterial clusters at the biofilm-enamel interface. Similar 3D architecture was observed in plaque-biofilms formed in vivo in the presence of sucrose. The formation of complex 3D architectures creates spatially heterogeneous acidic microenvironments in close proximity of enamel surface, which might correlate with the localized pattern of the onset of carious lesions(white spot like) on teeth.

关键词： biofilms demineralization dental caries exopolysaccharides microcolonies pH microenvironments plaque Streptococcus mutans

Upgrading pyrolytic carbon-blacks (CBp) from end-of-life tires: Characteristics and modification methodologies

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2020年第2期14卷 9-25页

作者： Jiaxue Yu Junqing Xu Zhenchen Li Wenzhi He Juwen Huang Junshi Xu Guangming Li State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China Shanghai Tire Craftsman Technology Co. Ltd.Shanghai 201400China

Over 1 billion end-of-life tires(ELTs)are generating annually,and 4 billion ELTs are currently abandoned in landfills and stockpiles worldwide,according to the statistics,leading to the environmental and health risks.To circumvent these issues,pyrolysis,as an attractive thermochemical process,has been addressed to tackle the ELTs'problem to reduce the risks as well as increase the material recycling.However,due to the lack of systematic characteristic analysis and modification methods,poor quality of CBp limits the improvement of ELTs pyrolysis in industry applications,which plays a crucial role in the economic feasibility of pyrolysis process.In this review,we have summarized the state-of-the-art characteristics and modification methodologies of the upgrading of CBp,to in-depth understand the surface microstructures and physiochemical properties o f CBp for the foundation for modification afterwards.By virtue of the proper selection of modification methods and modifying agents,the new generation of multifunctional carbon materials with desired properties can be instead of the traditional materials of CB,promising broader and various application fields.

关键词： Pyrolysis carbon-blacks CBp Post-pyrolysis demineralization Surface modification

Effect of ash removal on structure and pyrolysis/gasification reactivity of a Chinese bituminous coal

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2020年第3期7卷 444-455页

作者： Qing He Yan Gong Lu Ding Xingjun Wang Guangsuo Yu Institute of Clean Coal Technology East China University of Science and TechnologyShanghai200237China State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering Ningxia UniversityYinchuan750021NingxiaChina

In this study,the effect of ash removal on Shenfu bituminous coal was investigated.The coal was pretreated by hydrofluoric acid(HF)pickling,and the raw/pretreated coal chars were prepared at 900°C in a fixed bed reactor.The structure of coal and char were detected by Fourier transform infrared(FTIR)and Raman spectroscopy.The reactivity was tested in a thermogravimetric analyzer,including coal pyrolysis and char gasification.The reaction kinetics was analyzed through the Coats–Redfern method,master plots,the model-free and model-fitting method.The results show that the HF pickling can remove silicon from coal efficiently,and the macromolecular framework of coal is quite stable according to FTIR.The Raman parameters imply some carbonaceous structure on coal surface changed.For slow pyrolysis of coal,the effect of heating rate is considered.The changes of pyrolysis characteristics and kinetics are insignificant.For char gasification,the reactivity under isothermal and non-isothermal condition are discussed with an emphasis in different residence time of devolatilization process.In kinetic control region(low temperature),the activation energy(Ea)is very close(about 240 kJ/mol)for all chars.With the temperature increases,the reactivity of raw coal char is more easily suffered by diffusion.The random pore model is more suitable for the ash-free coal char,and the char with long residence time has a larger value of structural parameterψand smaller value of pre-exponential factor A.The Ea calculated by model-fitting and model-free method were in good agreement.

关键词： Gasification Pyrolysis demineralization Kinetics Structure evolution Master plot