uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Chen, Song
Publications (10 of 26) Show all publications
Chen, S., Wang, S., Li, H. & Kerstin, F. (2018). Eu3+ doped monetite and its use as fluorescent agent for dental restorations. Ceramics International, 44(9), 10510-10516
Open this publication in new window or tab >>Eu3+ doped monetite and its use as fluorescent agent for dental restorations
2018 (English)In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 44, no 9, p. 10510-10516Article in journal (Refereed) Published
Abstract [en]

It is essential but challenging to distinguish the dental restorations from the surrounding teeth when removing filling materials from cavity. In this study, Eu3+ doped monetite was proposed as a fluorescent agent for dental restorations to meet this challenge. Eu3+ doped monetite with enhanced fluorescent property was obtained via a precipitation method. The presence of Eu3+ could prevent the phase transformation of brushite to monetite. However, all the brushite particles transformed to monetite at 300 degrees C and to tricalcium phosphate at 800 degrees C. The emission intensity increased with the addition of Eu3+ and reached the maximum when 12 mol% Eu3+ was added into the aqueous solution. With either 254 nm or 393 nm excitation, Eu3+ doped monetite showed the strongest fluorescence emission peaking at 616 nm and other two moderate bands peaking at 699 nm and 593 nm. The excitation spectra at the emission wavelength of 616 nm showed strong absorption peaks at 254 nm and 393 nm. We further investigate the fluorescence properties of Eu3+ doped monetite in one type of dental restorations. Glass ionomer cement with Eu3+ doped monetite exhibited clear fluoresce with origin color under UV irradiation at 254 nm, showing that Eu3+ doped monetite is a promising fluorescent agent for dental restorations.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Physical Chemistry Materials Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-346521 (URN)10.1016/j.ceramint.2018.03.068 (DOI)000431470200063 ()
Available from: 2018-03-19 Created: 2018-03-19 Last updated: 2018-11-08Bibliographically approved
Liu, J., Chen, S., Papadakis, R. & Li, H. (2018). Nanoresolution patterning of hydrogenated graphene by electron beam induced C-H dissociation. Nanotechnology, 29(41), Article ID 415304.
Open this publication in new window or tab >>Nanoresolution patterning of hydrogenated graphene by electron beam induced C-H dissociation
2018 (English)In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 29, no 41, article id 415304Article in journal (Refereed) Published
Abstract [en]

Direct writing of semi-conductive or insulative nanopatterns on graphene surfaces is one of the major challenges in the application of graphene in flexible and transparent electronic devices. Here, we demonstrate that nanoresolution patterning on hydrogenated graphene can be approached by using electron beam induced C-H dissociation when the electron accelerating voltage is beyond a critical voltage of 3 kV. The resolution of the patterning reaches 18 nm and remains constant as the accelerating voltage is beyond 15 kV. The origin of the nanoresolution pattering as well as the dependence of the resolution on voltage in this technique is well explained by studying the cross-section of the C-H bond under electron impact. This work constitutes a new approach to fabricate graphene-based electronic nanodevices, with the reduced hydrogenated graphene channel utilized as conductive or semi-conductive counterpart in the structure.

Keywords
hydrogenated graphene, nanopatterning, electron beam irradiation
National Category
Nano Technology
Identifiers
urn:nbn:se:uu:diva-363091 (URN)10.1088/1361-6528/aad651 (DOI)000441307500001 ()30051882 (PubMedID)
Available from: 2018-10-16 Created: 2018-10-16 Last updated: 2018-10-16Bibliographically approved
Chen, S., Shi, L., Luo, J. & Engqvist, H. (2018). Novel Fast-Setting Mineral Trioxide Aggregate: Its Formulation, Chemical-Physical Properties, and Cytocompatibility. ACS Applied Materials and Interfaces, 10(24), 20334-20341
Open this publication in new window or tab >>Novel Fast-Setting Mineral Trioxide Aggregate: Its Formulation, Chemical-Physical Properties, and Cytocompatibility
2018 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 24, p. 20334-20341Article in journal (Refereed) Published
Abstract [en]

One of the main drawbacks that limits the application of mineral trioxide aggregate (MTA) in dental field is its long setting time. Mineral trioxide aggregate with accelerated setting properties and excellent chemical-physical and biological properties is still required. In this study, an innovative mineral trioxide aggregate, which consists of calcium silicates, calcium aluminates, and zirconium oxide, was designed to obtain fast-setting property. The optimized formulation can achieve initial setting in 10 min and final setting in 15 min, which are much faster than commercial mineral trioxide aggregate. In addition, the optimized fast-setting MTA showed adequate radiopacity and good biocompatibility. The ion concentrations after storage in water for 1 day were 52.3 mg/L Ca, 67.7 mg/L Al, 48.8 mg/L Si, and 11.7 mg/L Mg. The hydration products of hardened cements were investigated by X-ray diffraction, scanning electron microscopy, and Fourier transform infrared, showing the accelerated setting time was due to the formation of honeycomb-like calcium silicate hydrate gel. The novel MTA could be a promising material for dental applications.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
Keywords
mineral trioxide aggregate, dental cements, fast setting, calcium silicates, calcium aluminates
National Category
Materials Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-358684 (URN)10.1021/acsami.8b04946 (DOI)000436211500015 ()29873476 (PubMedID)
Available from: 2018-09-05 Created: 2018-09-05 Last updated: 2018-09-06Bibliographically approved
Liu, J., Chen, S., Wang, Y. & Li, H. (2018). Observation and characterisation of the surface hardness enhancement of the laser remelted NiCrBSi coating. International Journal of Surface Science and Engineering, 12(4), 336-346
Open this publication in new window or tab >>Observation and characterisation of the surface hardness enhancement of the laser remelted NiCrBSi coating
2018 (English)In: International Journal of Surface Science and Engineering, ISSN 1749-785X, E-ISSN 1749-7868, Vol. 12, no 4, p. 336-346Article in journal (Refereed) Published
Abstract [en]

The hardness enhancement on the surface of the laser remelted NiCrBSi coating was observed and characterised by employing X-ray photoelectron microscopy and nanoindentation techniques. The result indicates that, under the line energy density of 80 J/rnm, there is an agglomeration of the borides on the top 20 nm of the remelted coating that significantly enhanced the surface hardness as high as 1.5-fold stronger to 13 GPa than that of the main body of 8.5 GPa. Owing to the high concentration of the borides, the elemental distribution of the remelted surface has been modified significantly. In addition by varying the laser energy, the depth of the surface enhanced regions can be modified.

Keywords
laser remelting, NiCrBSi coating, surface hardness, tuneable depth
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:uu:diva-371063 (URN)10.1504/IJSURFSE.2018.096151 (DOI)000450125300005 ()
Available from: 2018-12-19 Created: 2018-12-19 Last updated: 2018-12-19Bibliographically approved
Chen, S., Öhman, C., Jefferies, S. R., Gray, H., Xia, W. & Engqvist, H. (2016). Compressive fatigue limit of four types of dental restorative materials. Journal of The Mechanical Behavior of Biomedical Materials, 61, 283-289
Open this publication in new window or tab >>Compressive fatigue limit of four types of dental restorative materials
Show others...
2016 (English)In: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 61, p. 283-289Article in journal (Refereed) Published
Abstract [en]

The purpose of this study was to evaluate the quasi-static compressive strength and the compressive fatigue limit of four different dental restorative materials, before and after aging in distilled water for 30 days. A conventional glass ionomer cement (Fuji IX GP; IG), a zinc-reinforced glass ionomer cement (Chemfil rock; CF), a light curable resin-reinforced glass ionomer cement (Fuji II LC; LC) and a resin-based composite (Quixfil; QF) were investigated. Cylindrical specimens (4 mm in diameter and 6 mm in height) were prepared according to the manufacturer's instructions. The compressive fatigue limit was obtained using the staircase method. Samples were tested in distilled water at 37 degrees C, at a frequency of 10 Hz with 10(5) cycles set as run-out. 17 fatigue samples were tested for each group. Two-way ANOVA and one-way ANOVA followed by Tukey's post-hoc test were used to analyze the results. Among the four types of materials, the resin-based composite exhibited the highest compressive strength (244 +/- 13.0 MPa) and compressive fatigue limit (134 +/- 7.8 MPa), followed by the light-cured resin reinforced glass ionomer cement (168 +/- 8.5 MPa and 92 +/- 6.6 MPa, respectively) after one day of storage in distilled water. After being stored for 30 days, all specimens showed an increase in compressive strength. Aging showed no effect on the compressive fatigue limit of the resin-based composite and the light-cured resin reinforced glass ionomer cement, however, the conventional glass ionomer cements showed a drastic decrease (37% for IG, 31% for CF) in compressive fatigue limit. In conclusion, in the present study, resin modified GIC and resin-based composite were found to have superior mechanical properties to conventional GIC.

Keywords
Dental restorative materials; Fatigue; Aging; Compressive
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-281942 (URN)10.1016/j.jmbbm.2016.03.031 (DOI)000380080400026 ()27085845 (PubMedID)
Available from: 2016-03-31 Created: 2016-03-31 Last updated: 2018-02-08Bibliographically approved
Chen, S., Mestres, G., Lan, W., Xia, W. & Engqvist, H. (2016). Cytotoxicity of modified glass ionomer cement on odontoblast cells. Journal of materials science. Materials in medicine, 27(7), Article ID 116.
Open this publication in new window or tab >>Cytotoxicity of modified glass ionomer cement on odontoblast cells
Show others...
2016 (English)In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 27, no 7, article id 116Article in journal (Refereed) Published
Abstract [en]

Recently a modified glass ionomer cement (GIC) with enhanced bioactivity due to the incorporation of wollastonite or mineral trioxide aggregate (MTA) has been reported. The aim of this study was to evaluate the cytotoxic effect of the modified GIC on odontoblast-like cells. The cytotoxicity of a conventional GIC, wollastonite modified GIC (W-mGIC), MTA modified GIC (M-mGIC) and MTA cement has been evaluated using cement extracts, a culture media modified by the cement. Ion concentration and pH of each material in the culture media were measured and correlated to the results of the cytotoxicity study. Among the four groups, conventional GIC showed the most cytotoxicity effect, followed by W-mGIC and M-mGIC. MTA showed the least toxic effect. GIC showed the lowest pH (6.36) while MTA showed the highest (8.62). In terms of ion concentration, MTA showed the largest Ca2+ concentration (467.3 mg/L) while GIC showed the highest concentration of Si4+ (19.9 mg/L), Al3+ (7.2 mg/L) and Sr2+ (100.3 mg/L). Concentration of F- was under the detection limit (0.02 mg/L) for all samples. However the concentrations of these ions are considered too low to be toxic. Our study showed that the cytotoxicity of conventional GIC can be moderated by incorporating calcium silicate based ceramics. The modified GIC might be promising as novel dental restorative cements.

National Category
Cell Biology Materials Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-297514 (URN)10.1007/s10856-016-5729-y (DOI)000379031200002 ()27221819 (PubMedID)
Funder
Swedish Research Council, 2013-5419 2011-3399EU, FP7, Seventh Framework ProgrammeVINNOVALars Hierta Memorial Foundation, FO2014-0334
Available from: 2016-06-23 Created: 2016-06-23 Last updated: 2018-02-08Bibliographically approved
Chen, S., Cai, Y., Engqvist, H. & Xia, W. (2016). Enhanced bioactivity of glass ionomer cement by incorporating calcium silicates. Biomatter, 6, e1123842
Open this publication in new window or tab >>Enhanced bioactivity of glass ionomer cement by incorporating calcium silicates
2016 (English)In: Biomatter, ISSN 2159-2527, E-ISSN 2159-2535, Vol. 6, p. e1123842-Article in journal (Refereed) Published
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-284149 (URN)
External cooperation:
Available from: 2016-04-15 Created: 2016-04-15 Last updated: 2018-02-08
Chen, S., Cai, Y., Engqvist, H. & Xia, W. (2016). Enhanced bioactivity of glass ionomer cement by incorporating calcium silicates. Biomatter, 6(1), e1123842-1-e1123842-13
Open this publication in new window or tab >>Enhanced bioactivity of glass ionomer cement by incorporating calcium silicates
2016 (English)In: Biomatter, ISSN 2159-2527, E-ISSN 2159-2535, Vol. 6, no 1, p. e1123842-1-e1123842-13Article in journal (Refereed) Published
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-281936 (URN)
External cooperation:
Available from: 2016-03-31 Created: 2016-03-31 Last updated: 2018-02-08
Chen, S. (2016). Glass Ionomer Cements with Improved Bioactive and Antibacterial Properties. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Glass Ionomer Cements with Improved Bioactive and Antibacterial Properties
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Dental restorative cements are placed in a harsh oral environment where they are subjected to thermal shock, chemical degradation, and repeating masticatory force. The ideal restorative dental cements should have superior mechanical properties, chemical stability, aesthetic, good handling properties, biocompatibility, antibacterial properties, and preferably bioactivity. This thesis presents research on dental restorative cements with enhanced properties. The overall aim was to increase the bioactivity and antibacterial properties of dental restorative cements without affecting their other properties.

The effect from adding calcium silicate to glass ionomer cement (GIC) was investigated. The results showed that calcium silicate could increase the bioactivity and reduce the cytotoxicity of conventional glass ionomer cement without compromising its setting and mechanical properties.

Hydroxyapatite (HA) with a high aspect ratio and thin nacreous-layered monetite sheets were also synthesized. Nano HA particles with an aspect ratio of 50 can be synthesized by both precipitation and hydrothermal methods. The aspect ratio was controlled via the pH of reaction medium. Thin nacreous-layered monetite sheets were synthesized through a self-assembly process in the presence of an amine based cationic quaternary surfactant. Temperature, pH, and presence of surfactant played essential roles in forming the nacreous-layered monetite sheets. Then the effect from adding silver doped HA and monetite particles was investigated. The results showed that the antibacterial properties of GIC could be increased by incorporating silver doped HA and monetite particles. Further examination showed that the pH change, F- ion release, and concentration of released Ag+ ions were not responsible for the improved antibacterial properties.

The quasi-static strengths and compressive fatigue limits of four types of the most commonly used dental restorations were evaluated. In our study, resin modified GIC and resin-based composite showed superior static compressive strength and fatigue limits compared to conventional GIC. The static compressive strength of dental cements increased with the aging time. However, aging had no effect on the compressive fatigue limit of resin modified GIC and resin-based composite. The compressive fatigue limit of conventional GIC even showed a drastic decrease after aging.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. p. 62
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1413
Keywords
biomaterial, glass ionomer cement, bioactivity, hydroxyapatite, monetite, calcium silicate
National Category
Biomaterials Science
Identifiers
urn:nbn:se:uu:diva-301924 (URN)978-91-554-9670-8 (ISBN)
Public defence
2016-10-14, Å2005, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2016-09-21 Created: 2016-08-25 Last updated: 2018-02-08
Chen, S., Mestres, G., Lan, W., Xia, W. & Engqvist, H. (2016). In vitro cytotoxicity of dental cements on odontoblast cells. In: : . Paper presented at European Chapter Meeting of the Tissue Engineering and Regenerative Medicine International Society 2016.
Open this publication in new window or tab >>In vitro cytotoxicity of dental cements on odontoblast cells
Show others...
2016 (English)Conference paper, Poster (with or without abstract) (Refereed)
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-300710 (URN)
Conference
European Chapter Meeting of the Tissue Engineering and Regenerative Medicine International Society 2016
Available from: 2016-08-11 Created: 2016-08-11 Last updated: 2018-02-08
Organisations

Search in DiVA

Show all publications