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Effect of colouring green stage zirconia on the adhesion of veneering ceramics with different thermal expansion coefficients

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International Journal of Oral Science 2013年第4期5卷 236-241页

作者： Guliz Aktas Erdal Sahin Pekka Vallittu Mutlu zcan Lippo Lassila department of Prosthodontics Faculty of DentistryHacettepe University department of Biomaterials Science and Turku Clinical Biomaterials Centre University of Turku dental materials Unit Center for Dental and Oral MedicineClinic for Fixed and Removable Prosthodontics and Dental Materials ScienceUniversity of Zrich

This study evaluated the adhesion of zirconia core ceramics with their corresponding veneering ceramics, having different thermal expansion coefficients （TECs）, when zirconia ceramics were coloured at green stage. Zirconia blocks （N=240; 6 mm x 7 mm x 7 mm） were manufactured from two materials namely, ICE Zirconia （Group 1） and Prettau Zirconia （Group 2）. In their green stage, they were randomly divided into two groups. Half of the specimens were coloured with colouring liquid （shade A2）, Three different veneering ceramics with different TEC （ICE Ceramic, GC Initial Zr and IPS e.max Ceram） were fired on both coloured and non-coloured zirconia cores. Specimens of high noble alloys （Esteticor Plus） veneered with ceramic （VM 13）（n= 16） acted as the control group. Core-veneer interface of the specimens were subjected to shear force in the Universal Testing Machine （0.5 mm-min-1）. Neither the zirconia core material （P=0.318） nor colouring （P=0.188） significantly affected the results （three-way analysis of variance, Tukey＇s test）. But the results were significantly affected by the veneering ceramic （P=0.000）. Control group exhibited significantly higher mean bond strength values （45.7__.8） MPa than all other tested groups （（27.1__.4.1）-（39.7__.4.7） and （27.4__.5.6）-（35.9___4.7） MPa with and without colouring, respectively）（P^0.001）. While in zirconia-veneer test groups, predominantly mixed type of failures were observed with the veneering ceramic covering ~ 1/3 of the substrate surface, in the metal-ceramic group, veneering ceramic was left adhered 1/3 of the metal surface. Colouring zirconia did not impair adhesion of veneering ceramic, but veneering ceramic had a significant influence on the core-veneer adhesion. Metal-ceramic adhesion was more reliable than all zirconia-veneer ceramics tested.

关键词： adhesion bond strength colouring~ thermal expansion coefficient zirconia

Biomimetic AgNPs@antimicrobial peptide/silk fibroin coating for infection-trigger antibacterial capability and enhanced osseointegration

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Bioactive materials 2023年第2期20卷 64-80页

作者： Wenhao Zhou Tian Bai Lan Wang Yan Cheng Dandan Xia Sen Yu Yufeng Zheng Shaanxi Key Laboratory of Biomedical Metallic materials Northwest Institute for Non-ferrous Metal ResearchXi’an710016China Department of Dental Materials Peking University School and Hospital of StomatologyBeijing100081China School of materials Science and Engineering Peking UniversityBeijing100871China

Endowing implant surfaces with combined antibacterial and osteogenic properties by drug-loaded coatings has made great strides,but how to achieve the combined excellence of infection-triggered bactericidal and in vivo-proven osteogenic activities without causing bacterial resistance still remains a formidable challenge.Herein,antimicrobial peptides(AMPs)with osteogenic fragments were designed and complexed on the surface of silver nanoparticle(AgNP)through hydrogen bonding,and the collagen structure-bionic silk fibroin(SF)was applied to carry AgNPs@AMPs to achieve infection-triggered antibacterial and osteointegration.As verified by TEM,AMPs contributed to the dispersion and size-regulation of AgNPs,with a particle size of about 20 nm,and a clear protein corona structure was observed on the particle surface.The release curve of silver ion displayed that the SF-based coating owned sensitive pH-responsive properties.In the antibacterial test against S.aureus for up to 21 days,the antibacterial rate had always remained above 99%.Meanwhile,the underlying mechanism was revealed,originating from the destruction of the bacterial cell membranes and ROS generation.The SF-based coating was conducive to the adhesion,diffusion,and proliferation of bone marrow stem cells(BMSCs)on the surface,and promoted the expression of osteogenic genes and collagen secretion.The in vivo implantation results showed that compared with the untreated Ti implants,SF-based coating enhanced osseointegration at week 4 and 8.Overall,the AgNPs@AMPs-loaded SF-based coating presented the ability to synergistically inhibit bacteria and promote osseointegration,possessing tremendous potential application prospects in bone defects and related-infection treatments.

关键词： Antimicrobial peptides AgNPs Antibacterial Osteointegration Titanium

Mechanical properties and corrosion resistance of low rigidity quaternary titanium alloy for biomedical applications

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中国有色金属学会会刊：英文版 2009年第4期19卷 862-865页

作者： Han-Cheol CHOE Viswanat han S.SAJI Yeong-Mu KO Department of Dental Materials College of DentistryChosun University

Electrochemical corrosion of Ti-35Nb-5Ta-7Zr alloy fabricated by arc melting and heat treatment process was studied in 0.9% NaCl at(37±1) ℃.Phase and microstructure of the fabricated alloy were investigated using X-ray diffractometer and scanning electron microscope.Mechanical properties such as yield strength and elastic modulus of the alloy were determined by tensile test.Potentiodynamic polarization technique and impedance spectroscopy were employed to study the corrosion behavior.The results of the study were compared with those obtained for Ti-6Al-4V commercial alloy.The result of the study supports feasibility of Ti-35Nb-5Ta-7Zr alloy for implant applications.

关键词：生物医学应用钛合金力学性能耐腐蚀性扫描电子显微镜四元刚性 X射线衍射仪

Influence of Aging and 2-hydroxyethyl-methacrylate Content on the Color Stability of Experimental 2-hydroxyethyl-methacrylate-added dental Glass Ionomers

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Journal of materials Science & Technology 2010年第4期26卷 379-384页

作者： Bin Yu Guangfeng Zhao Honam Lim Jinik Lira Yongkeun Lee Department of Dental Materials and Center for dental materials School of Dentistry Kyung Hee University Seoul Korea Denforus co. Seaul Korea

Color stability of dental resin modified glass ionomer （RMGI） has been a challenge to dentistry; therefore, systematic changes in 2-hydroxyethyl methacrylate （HEMA） content were performed experimentally to find an idea to enhance the color stability. Changes in color （△E＊ab） and color coordinates （△L＊, △a＊ and △b＊） of experimental 10-50 wt pct HEMA-added dental glass ionomers （HAGIs） and corresponding RMGIs were determined after 5000 cycles of thermocycling. Color changes of HAGIs were not influenced by the HEMA content while △L＊, △a＊ and △b＊ values were influenced by the HEMA content. Color stability of 30% or 40% HEMA-added HAGIs was not different from those of the commercial RMGIs. Since the influence of HEMA itself on the color stability of HAGIs was limited, compositional modification to increase the color stability of these materials should be developed.

关键词： Glass ionomer 2-hydroxyethyl methacrylate （HEMA） Color coordinate Thermocycling

Effect of liner and porcelain application on zirconia surface structure and composition

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International Journal of Oral Science 2016年第3期8卷 164-171页

作者： Tariq F Alghazzawi Gregg M Janowski department of Prosthetic dental Sciences College of DentistryTaibah University department of materials Science and Engineering School of EngineeringThe University of Alabama at Birmingham

The purpose of this study was to determine if there is an effect of liner and porcelain application （layering and pressing techniques） on the surface of yttria-stabilized tetragonal zirconia polycrystals （Y-TZP）, which were exposed to permutations of liner, layered porcelain, and pressed porcelain. Scanning electron microscope （SEM）/energy dispersive spectroscope （EDS） was used to identify changes in composition and microstructure after removing liner and porcelain with hydrofluoric acid. Simulated aging was also conducted to determine the effect of liner and porcelain on low-temperature degradation. The control group had a typical equiaxed grain structure, referred to as unaffected. When covered with liner or porcelain, some areas changed in structure and composition and were termed affected. The frequency of affected sbructure decreased when liner was covered with either layered porcelain or pressed porcelain. There were statistical differences （P〈0.05） in the composition between affected and unaffected for zirconium （layered porcelain with liner： affected = 60% （0.8%）（m/m）, unaffected = 69% （4%）, layered porcelain without liner： affected = 59% （3%）, unaffected = 65% （3%）） and oxygen （layered porcelain with liner： affected = 35% （2%）, unaffected = 26% （4%）, layered porcelain without liner： affected = 35% （3%）, unaffected = 30% （2%））. However, there were statistical differences （P〈0.05） in the composition for zirconium and oxygen of the aged layered porcelain without liner only. The liner should not be used before porcelain application, especially when using the layering technique for zirconia restorations. Furthermore, pressing should be considered the technique of choice over layering.

关键词： aging coefficient of thermal expansion energy dispersive spectroscopy layering of porcelain pressing of porcelain scanning electron microscope zirconia

The Role of Host-derived Dentinal Matrix Metalloproteinases in Reducing Dentin Bonding of Resin Adhesives

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International Journal of Oral Science 2009年第4期1卷 163-176页

作者： Matthias Kern department of Prosthodontics Propaedeutics and Dental Materials Christians-Albrechts UniversityKiel Germany

Dentin matrix metalloproteinases （MMPs） are a family of host-derived proteolytic enzymes trapped within mineralized dentin matrix, which have the ability to hydrolyze the organic matrix of demineralized dentin. After bonding with resins to dentin there are usually some exposed collagen fibrils at the bottom of the hybrid layer owing to imperfect resin impregnation of the demineralized dentin matrix. Exposed collagen fibrils might be affected by MMPs inducing hydrolytic degradation, which might result in reduced bond strength.Most MMPs are synthesized and released from odontoblasts in the form of proenzymes, requiring activation to degrade extracellular matrix components. Unfortunately, they can be activated by modem self-etch and etch-and-rinse adhe- sives. The aim of this review is to summarize the current knowledge of the role of dentinal host-derived MMPs in dentin matrix degradation. We also discuss various available MMP inhibitors, especially chlorhexidine, and suggest that they could provide a potential pathway for inhibiting collagen degradation in bonding interfaces thereby increasing dentin bonding durability.

关键词： bonding matrix metalloproteinases（MMPs） MMP inhibitors chlorhexidine

Evaluation of zirconia–porcelain interface using X-ray diffraction

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International Journal of Oral Science 2015年第3期7卷 187-195页

作者： Tariq F Alghazzawi Gregg M Janowski department of materials Science and Engineering School of Engineering The University of Alabama at Birmingham department of Prosthetic dental Sciences College of Dentistry Taibah University

The aim of this study was to determine if accelerated aging of porcelain veneering had an effect on the surface properties specific to a tetragonal-to-monoclinic transformation（TMT） of zirconia restorations. Thirty-six zirconia samples were milled and sintered to simulate core fabrication followed by exposure to various combinations of surface treatments including as-received（control）,hydrofluoric acid（HF）, application of liner plus firings, application of porcelain by manual layering and pressing with firing, plus accelerated aging. The quantity of transformed tetragonal to monoclinic phases was analyzed utilized an X-ray diffractometer and one-way analysis of variance was used to analyze data. The control samples as provided from the dental laboratory after milling and sintering process had no TMT（X m5 0）. There was an effect on zirconia samples of HF application with TMT（X m5 0.8%） and liner plus HF application with TMT（X m5 8.7%）. There was an effect of aging on zirconia samples（no veneering） with significant TMT（X m5 70.25%）. Both manual and pressing techniques of porcelain applications reduced the TMT（manual, X m5 4.41%, pressing,X m5 11.57%）, although there was no statistical difference between them. It can be concluded that simulated applications of porcelain demonstrated the ability to protect zirconia from TMT after aging with no effect of a liner between different porcelain applications.The HF treatment also caused TMT.

关键词： aging hydrofluoric acid monoclinic pressing tetragonal X-ray diffraction

Effect of Different Titanium Surface Treatments on the Adhesion Test Result:dental Application

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Journal of Wuhan University of Technology(materials Science) 2023年第1期38卷 255-259页

作者： Alireza Valanezhad Masayoshi Suzue Sirus Safaee Mahdis Nesabi Mohammad Khodaei Shigeaki Abe Ikuya Watanabe department of dental and Biomedical materials Science Nagasaki UniversityNagasakiJapan Medical Education Development Center Nagasaki University HospitalNagasakiJapan materials Engineering Group Golpayegan College of EngineeringIsfahan University of TechnologyGolpayegan 87717-67498Iran

The aim of the study was to investigate the effect of different surface treatment of titanium(Ti)on the adhesion test results for dental application.Ti substrates roughened by 400 to 1500-grit SiC polish papers and alumina blasting,alkali treated by 5 molar(M)NaOH and KOH solutions and heat treated at the temperature range of 400-800℃were used in this study.The treated samples were subjected to the adhesion test.According to the results of the adhesion test,the adhesive strength showed the highest value for the blasted titanium among all polished and blasted samples.The Ti samples heated at 650℃showed the highest adhesive strength among all heat-treated samples.Further,the adhesion test results indicated the higher adhesive strength of chemically treated samples treated by NaOH rather than that by KOH.The polished and heated Ti samples showed the highest adhesive strength among all samples.

关键词： titanium implant surface treatment bonding strength anatase rutile

Dedifferentiated fat cells: an alternative source of adult multipotent cells from the adipose tissues

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International Journal of Oral Science 2011年第3期3卷 117-124页

作者： Jie-fei Shen Atsunori Sugawara Joe Yamashita Hideo Ogura Soh Sato department of Periodontology School of Life Dentistry at Niigata Nippon Dental University Niigata 951-1500 Japan Department of Dental Materials School of Life Dentistry at Niigata Nippon Dental University Niigata 951-1500 Japan

When adipose-derived stem cells （ASCs） arc retrieved from the stromal vascular portion of adipose tissue, a large amount of mature adipocytes are often discarded. However, by modified ceiling culture technique based on their buoyancy, mature adipocytes can be easily isolated from the adipose cell suspension and dediffercn- tiated into lipid-frce fibroblast-like cells, named dediffercntiated fat （DFAT） cells. DFAT cells rc-establish active proliferation ability and undertake multipotent capacities. Compared with ASCs and other adult stem cells, DFAT cells showed unique advantages in their abundance, isolation and homogeneity. In this concise review, the establishment and culture methods of DFAT cells arc introduced and the current profiles of their cellular nature are summarized. Under proper inducti~,n culture in vitro or environment in vivo, DFAT cells could demonstrate adipogenic, osteogenic, chondrogenie and myogenic potentials. In angiogenie conditions, DFAT cells could exhibit perivascular characteristics antt elicit neovascularization. Our preliminary findings also suggested the pericyte phenotype underlying such cell lineage, which supported a novel interpretation about the common origin of mesenchymal stem cells and tissue-specific stem cells within blood vessel walls. Current research on DFAT cells indicated that this alternative source of adult multipotent cells has great potential in tissue engineering and regenerative medicine.

关键词： dedifferentiated fat cells adult stem cells adipose tissue mesenchymal stem cells regenerative medicine