scholarly journals Novel Polymerization of Dental Composites Using Near-Infrared-Induced Internal Upconversion Blue Luminescence

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4304
Author(s):  
Shu-Fen Chuang ◽  
Chu-Chun Liao ◽  
Jui-Che Lin ◽  
Yu-Cheng Chou ◽  
Tsung-Lin Lee ◽  
...  
Keyword(s):  
Near Infrared ◽  
Upconversion Luminescence ◽  
Blue Emission ◽  
Polymerization Reaction ◽  
Dental Composites ◽  
Resin Composites ◽  
Dental Resin ◽  
Base Composite ◽  
Different Depths ◽  
Co Doped

Blue light (BL) curing on dental resin composites results in gradient polymerization. By incorporating upconversion phosphors (UP) in resin composites, near-infrared (NIR) irradiation may activate internal blue emission and a polymerization reaction. This study was aimed to evaluate the competency of the NIR-to-BL upconversion luminance in polymerizing dental composites and to assess the appropriate UP content and curing protocol. NaYF4 (Yb3+/Tm3+ co-doped) powder exhibiting 476-nm blue emission under 980-nm NIR was adapted and ball-milled for 4–8 h to obtain different particles. The bare particles were assessed for their emission intensities, and also added into a base composite Z100 (3M EPSE) to evaluate their ability in enhancing polymerization under NIR irradiation. Experimental composites were prepared by dispensing the selected powder and Z100 at different ratios (0, 5, 10 wt% UP). These composites were irradiated under different protocols (BL, NIR, or their combinations), and the microhardness at the irradiated surface and different depths were determined. The results showed that unground UP (d50 = 1.9 μm) exhibited the highest luminescence, while the incorporation of 0.4-μm particles obtained the highest microhardness. The combined 20-s BL and 20–120-s NIR significantly increased the microhardness on the surface and internal depths compared to BL correspondents. The 5% UP effectively enhanced the microhardness under 80-s NIR irradiation but was surpassed by 10% UP with longer NIR irradiation. The combined BL-NIR curing could be an effective approach to polymerize dental composites, while the intensity of upconversion luminescence was related to specific UP particle size and content. Incorporation of 5–10% UP facilitates NIR upconversion polymerization on dental composites.

Blue Upconversion Luminescence from Phosphor Tm3+/Yb3+ Co-Doped Gd2Mo3O9

2013 ◽  
Vol 683 ◽  
pp. 3-6
Author(s):  
Jia Yue Sun ◽  
Bing Xue ◽  
Guang Chao Sun ◽  
Dian Peng Cui ◽  
Hai Yan Du
Keyword(s):  
Solid State ◽  
Upconversion Luminescence ◽  
Blue Emission ◽  
Solid State Reaction Method ◽  
Solid State Lighting ◽  
Red Emission ◽  
Reaction Method ◽  
X Ray ◽  
Strong Blue Emission ◽  
Co Doped

The upconversion (UC) luminescence properties of phosphor Tm3+/Yb3+co-doped Gd2Mo3O9were investigated in detail. Tm3+/Yb3+co-doped Gd2Mo3O9was prepared by solid-state reaction method using Na2CO3as flux and characterized by powder X-ray diffractometry. Under 980nm excitation, Tm3+/Yb3+co-doped Gd2Mo3O9has exhibited a weak red emission near 651nm and strong blue emission at 476nm. Tm3+/Yb3+co-doped Gd2Mo3O9phosphor has been considered as a better candidate in solid-state lighting applications.

scholarly journals Development of Chlorhexidine Loaded Halloysite Nanotube Based Experimental Resin Composite with Enhanced Physico-Mechanical and Biological Properties for Dental Applications

2020 ◽  
Vol 4 (2) ◽  
pp. 81 ◽  
Author(s):  
Tejas Barot ◽  
Deepak Rawtani ◽  
Pratik Kulkarni
Keyword(s):  
Mechanical Properties ◽  
Resin Composite ◽  
Biological Properties ◽  
Degree Of Conversion ◽  
Dental Composites ◽  
Resin Composites ◽  
Dental Resin ◽  
Dental Resin Composites ◽  
Mass Fractions ◽  
Nih 3T3

Objective: The objective of this study was to explore the effect of Chlorhexidine-loaded Halloysite nanotubes (HNT/CHX) fillers (diverse mass fractions from 1 to 10 wt.%) on physicochemical, morphological and biological properties of newly developed experimental dental resin composite, in order to compare with the properties of composites composed of conventional glass fillers. Methods: The dental resin composites were prepared by incorporating various proportions of HNT/CHX. Six different groups of specimens: control group and five groups composed of varied mass fractions of HNT/CHX (e.g., 1.0, 2.5, 5.0, 7.5 and 10 wt.%) as fillers in each group were fabricated. Mechanical properties of the composites were monitored, using UTM. The degree of conversion of dental resin composites and their depth of cure were also evaluated. Antimicrobial properties of dental composites were studied in vitro by applying agar diffusion test on strain Streptococcus mutans and cytotoxicity were studied using NIH-3T3 cell line. Results: The incorporation of varied mass fractions (1.0 to 5.0 wt.%) of HNT/CHX in dental resins composites enhanced mechanical properties considerably with significant antibacterial activity. The slight decrease in curing depth and degree of conversion values of composites indicates its durability. No cytotoxicity was noticed on NIH-3T3 cell lines. Significance: Consistent distribution of HNT/CHX as a filler into dental composites could substantially improve not only mechanical properties but also biological properties of dental composites.

Comparative Effectiveness of Two Light Curing Units on the Properties of Dental Resin Composites

2020 ◽  
Keyword(s):  
Light Emitting Diodes ◽  
Polymerization Reaction ◽  
Resin Composites ◽  
Micro Hardness ◽  
Dental Resin ◽  
Light Emitting ◽  
Dental Resin Composites ◽  
Light Intensities ◽  
Quartz Tungsten Halogen ◽  
Light Curing

Background: Setting of conventional glass ionomers cement and dental resin composites as filling materials is predominantly through polymerization reaction, which is usually induced by light. The objective of this study was to assess the temperature changes, light intensities, sorption and solubility capability and comparative micro hardness in Dental Resin Composites (DRC) by using two different light curing units that is Quartz Tungsten Halogen (QTH) and Light Emitting Diodes (LED). Methods: This analytical, experimental, in-vitro study was spanned over one month, conducted in the laboratory of Dental Materials, Dr. Ishrat-ul-Ibad Khan Institute of Oral Health Sciences. Through non-probability, convenient sampling, 60 samples of DRCs was prepared as 10mm in diameter and 2mm in thickness in the steel moulds by a single trained operator. Effect of heat generation, light intensities, sorption and solubility and micro hardness during polymerization of DRCs were all measured. Statistical analysis was done using SPSS with descriptive statistics and two sample independent t-tests. The p-value of <0.05 was considered significant at 95 % confidence level. Results: Mean surface micro hardness of DRC was found to be 15.48±0.46 and 18.26±0.53 when QTH and LED lamps were employed respectively. Whereas, mean light intensity of QTH and LED lamps were found to be 434 and 925mW/cm2. No significant difference in temperature change during polymerization reaction (p=0.128) and in sorption and solubility capability (p=0.001) of DRC was observed. Conclusion: Light-emitting diodes were evaluated to be more effective than Quartz Tungsten Halogen Light in achieving increased surface micro hardness of DRC. Keywords: Light; Glass Ionomer Cements; Tungsten; Hardness.

scholarly journals Volume and surface effects on two-photonic and three-photonic processes in dry co-doped upconversion nanocrystals

Nano Research ◽  
2021 ◽  
Author(s):  
Bettina Grauel ◽  
Christian Würth ◽  
Christian Homann ◽  
Lisa Krukewitt ◽  
Elina Andresen ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Near Infrared ◽  
Surface Passivation ◽  
Upconversion Luminescence ◽  
Three Dimensional ◽  
Solid Core ◽  
Excitation Power Density ◽  
Surface Protection ◽  
Upconversion Nanocrystals ◽  
Co Doped

AbstractDespite considerable advances in synthesizing high-quality core/shell upconversion (UC) nanocrystals (NC; UCNC) and UCNC photophysics, the application of near-infrared (NIR)-excitable lanthanide-doped UCNC in the life and material sciences is still hampered by the relatively low upconversion luminescence (UCL) of UCNC of small size or thin protecting shell. To obtain deeper insights into energy transfer and surface quenching processes involving Yb3+ and Er3+ ions, we examined energy loss processes in differently sized solid core NaYF4 nanocrystals doped with either Yb3+ (YbNC; 20% Yb3+) or Er3+ (ErNC; 2% Er3+) and co-doped with Yb3+ and Er3+ (YbErNC; 20% Yb3+ and 2% Er3+) without a surface protection shell and coated with a thin and a thick NaYF4 shell in comparison to single and co-doped bulk materials. Luminescence studies at 375 nm excitation demonstrate back-energy transfer (BET) from the 4G11/2 state of Er3+ to the 2F5/2 state of Yb3+, through which the red Er3+4F9/2 state is efficiently populated. Excitation power density (P)-dependent steady state and time-resolved photoluminescence measurements at different excitation and emission wavelengths enable to separate surface-related and volume-related effects for two-photonic and three-photonic processes involved in UCL and indicate a different influence of surface passivation on the green and red Er3+ emission. The intensity and lifetime of the latter respond particularly to an increase in volume of the active UCNC core. We provide a three-dimensional random walk model to describe these effects that can be used in the future to predict the UCL behavior of UCNC.

Photoluminescent properties of near-infrared excited blue emission in Yb, Tm co-doped LaGaO3 phosphors

2014 ◽  
Vol 40 (8) ◽  
pp. 13357-13361 ◽  
Author(s):  
Hyun Kyoung Yang ◽  
Ju Hyun Oh ◽  
Byung Kee Moon ◽  
Jung Hyun Jeong ◽  
Soung Soo Yi
Keyword(s):  
Near Infrared ◽  
Blue Emission ◽  
Co Doped

Comprehensive investigations of near infrared downshift and upconversion luminescence mechanisms in Yb3+ single-doped and Er3+,Yb3+ co-doped SiO2 inverse opals

2017 ◽  
Vol 19 (47) ◽  
pp. 31997-32006 ◽  
Author(s):  
Zhengwen Yang ◽  
Jianzhi Yang ◽  
Jianbei Qiu ◽  
Zhiguo Song
Keyword(s):  
Near Infrared ◽  
Upconversion Luminescence ◽  
Inverse Opals ◽  
Co Doped

Comprehensive investigations of near infrared (NIR) downshift and visible upconversion luminescence (UCL) mechanisms were carried out for Yb3+ single-doped and Er3+,Yb3+ co-doped SiO2 inverse opals under excitation at 256, 378, 520 and 980 nm.

Enhanced one-band near infrared upconversion luminescence of Yb3+-Tm3+ co-doped BiOCl1-xBrx nanosheet by Tuning band gap

2021 ◽  
pp. 118295
Author(s):  
Fangyu He ◽  
Yapai Song ◽  
Qi Wang ◽  
Yongjin Li ◽  
Zhengwen Yang ◽  
...  
Keyword(s):  
Band Gap ◽  
Near Infrared ◽  
Upconversion Luminescence ◽  
Co Doped

scholarly journals Polymerization kinetics of experimental resin composites functionalized with conventional (45S5) and a customized low-sodium fluoride-containing bioactive glass

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Matej Par ◽  
Katica Prskalo ◽  
Tobias T. Tauböck ◽  
Hrvoje Skenderovic ◽  
Thomas Attin ◽  
...  
Keyword(s):  
Bioactive Glass ◽  
Polymerization Kinetics ◽  
Light Transmittance ◽  
Polymerization Reaction ◽  
Resin Composites ◽  
Dental Resin ◽  
Low Sodium ◽  
Dental Resin Composites ◽  
Light Curing ◽  
Thick Layers

AbstractThis study aimed to investigate polymerization kinetics and curing light transmittance of two series of experimental dental resin composites filled with 0–40 wt% of either 45S5 bioactive glass (BG) or a customized low-Na F-containing BG. Polymerization kinetics in 0.1-mm and 2-mm thick layers were investigated through real-time degree of conversion measurements using a Fourier transform infrared (FTIR) spectrometer. FTIR spectra were continuously collected at a rate of 2 s−1 during light-curing (1340 mW/cm2). Light transmittance through 2-mm thick composite specimens was measured using a UV–Vis spectrometer at a rate of 20 s−1. Unlike BG 45S5, which led to a dose-dependent reduction in the rate and extent of polymerization, the customized low-Na F-containing BG showed a negligible influence on polymerization. The reduction in light transmittance of experimental composites due to the addition of the low-Na F-containing BG did not translate into impaired polymerization kinetics. Additionally, the comparison of polymerization kinetics between 0.1-mm and 2-mm thick layers revealed that polymerization inhibition identified for BG 45S5 was not mediated by an impaired light transmittance, indicating a direct effect of BG 45S5 on polymerization reaction. A customized low-Na F-containing BG showed favourable behaviour for being used as a functional filler in light-curing dental resin composites.

scholarly journals Flexural Strength and Depth of Cure of Single Shade Dental Composites

2021 ◽  
pp. 110-118
Author(s):  
Fatin A. Hasanain
Keyword(s):  
Flexural Strength ◽  
Testing Machine ◽  
Dental Composites ◽  
Resin Composites ◽  
Dental Resin ◽  
Depth Of Cure ◽  
Universal Testing ◽  
Significant Difference ◽  
Experimental Laboratory ◽  
Cylindrical Samples

Aims: This work aims to assess the flexural strength and depth of cure of Optishade, Omnichroma and Z350 dental resin composites. Study Design: Experimental Laboratory Study. Methods: To assess flexural strength as per ISO standards, 15 samples of each of the three materials were made (n=5) with the dimensions 25x2x2 mm. They were then subjected to 3 point bending testing on a universal testing machine. To assess depth of cure as per ISO standard, 15 cylindrical samples 4 mm in diameter and 6 mm in height were created (n=5) and scraping test was performed. Results: There was a significant difference between the 3 materials in both flexural strength and depth of cure. Z350 had the lowest depth of cure and the highest flexural strength. Conclusion: Within the limitations of this study, all three tested materials fell within the ISO requirementsfor dental resin compositesfor both flexural strength and depth of cure.

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