scholarly journals Flexural Strength, Elastic Modulus and Remineralizing Abilities of Bioactive Resin-Based Dental Sealants

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 61
Author(s):  
Maria Salem Ibrahim ◽  
Mana’a S. Alabbas ◽  
Khalid U. Alsomaly ◽  
Abdullah A. AlMansour ◽  
Alhareth Abdulaziz Aljouie ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Flexural Strength ◽  
Polarized Light ◽  
Surface Hardness ◽  
The Other ◽  
Bioactive Materials ◽  
Phosphate Ions ◽  
Human Enamel ◽  
Demineralized Enamel ◽  
Ph Cycling

Objective: To assess the remineralizing abilities and compare the flexural strength and elastic modulus of different bioactive pit and fissure sealants. Materials and Methods: Human enamel samples were randomly and blindly sealed with one of the following bioactive materials: BioCoat (Bc), ACTIVA KIDS (Av) and BeautiSealant (Bu). Seal-it (Si) was used as a non-bioactive sealant beside a control blank (B) group with no sealant. The sealed samples were subjected to a pH-cycling model (7 days of demineralization–remineralization cycles). The enamel surface hardness change (SHC), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) and polarized light microscopy were used to assess the remineralizing abilities of the studied sealants. Flexural strength and elastic modulus were also assessed following the ISO 4049 protocols. One-way analysis of variance (ANOVA) was used to analyze the results. Results: Bc sealant showed the highest FS and EM (p < 0.05). The contact with Bc and Bu sealants showed significantly lower %SHL (p < 0.05) in comparison to the other. These findings were supported by the results of SEM-EDX and polarized imaging by showing higher percentages of calcium and phosphate ions with the former sealants and thinner demineralized enamel bands. Conclusion: In this study, Bc showed the highest flexural strength. Bc and Bu sealants outperformed the other studied sealants in terms of their remineralization abilities.

Anticaries Potential of Commercial Dentifrices as Determined by Fluoridation and Remineralization Efficiency

2007 ◽  
Vol 8 (7) ◽  
pp. 1-10 ◽  
Author(s):  
Elias Casals ◽  
Tchilalo Boukpessi ◽  
Christina M. McQueen ◽  
Sandy L. Eversole ◽  
Robert V. Faller
Keyword(s):  
Surface Hardness ◽  
Reference Standard ◽  
Surface Microhardness ◽  
Fluoride Uptake ◽  
Human Enamel ◽  
Demineralized Enamel ◽  
Group 6 ◽  
Group 3 ◽  
Group 2

Abstract Aim The aim of this in vitro study was to investigate fluoride uptake in human enamel after use of commercially available toothpastes containing different fluoride compounds, or combinations of fluoride actives formulated into a single product, as a means of determining the efficiency of each formula for delivering caries preventing fluoride to demineralized (caries active) enamel. Methods and Materials Four test dentifrices and two controls were assessed and placed in groups as follows: Group 1: Lacer® (Spain); Group 2: Positive control-USP Reference Standard 1100 ppm F; Group 3: Fluocaril® Bi-Fluoré 250 (France); Group 4: Colgate Fluor Active (Denmark); Group 5: Elmex® (France); and Group 6: A placebo (formulated the same as the USP Reference Standard toothpaste with the exception that it contained < 1 ppm F). Cores 3 mm in diameter were removed from erupted human enamel specimens (extracted by local oral surgeons for orthodontic reasons) and stored in 1% Thymol solution prior to use. They were ground and polished to remove the natural fluoride rich enamel layer, then exposed to a demineralization solution, and assessed for surface microhardness to enable randomization for use in the study. Each group of five specimens underwent a daily pH cycling procedure that involved exposure to pooled human saliva (refreshed three times daily). The groups were then exposed to dentifrice slurries four times daily for one minute per exposure and to a demineralization solution for three hours. The cycling procedure was repeated for five days. Specimens were again analyzed for surface microhardness and fluoride uptake upon completion of five days of treatment. Results Average surface hardness: Groups 2 and 3 showed a statistically significant greater (p<0.05) change indicating greater remineralization compared to all other groups. The average change was 23.45 for Group 2 and 22.65 for Group 3. All other groups had changes ranging from 4.25-8.62. No other statistically significant differences were observed between groups. Fluoride uptake results: Groups 2 and 3 showed statistically significantly greater fluoride uptake versus all other groups (p <0.05). Groups 1 and 5 were significantly different from Group 6. No other statistically significant differences were observed for either analysis. Conclusions Of the marketed products included in the study, the Fluocaril® Bi-Fluoré 250 product formulation provided both the highest level of fluoride uptake and mineralization to the demineralized enamel. The clinical significance of these in vitro results is the confirmation Fluocaril® Bi-Fluoré 250 is effective at remineralizing enamel caries lesions. Citation Casals E, Boukpessi T, McQueen CM, Eversole SL, Faller RV. Anticaries Potential of Commercial Dentifrices as Determined by Fluoridation and Remineralization Efficiency. J Contemp Dent Pract 2007 November; (8)7:001-010.

scholarly journals Study on the Influence of the Grind Percentage Over the Surface Hardness and Modulus of Elasticity of Parts Made of ABS, P6.6 and POM through Nanoindentation

2019 ◽  
Vol 56 (1) ◽  
pp. 65-70
Author(s):  
Gheorghe Radu Emil Maries ◽  
Constantin Bungau ◽  
Dan Chira ◽  
Traian Costea ◽  
Danut-Eugeniu Mosteanu
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Surface Hardness ◽  
Acrylonitrile Butadiene Styrene ◽  
The Other ◽  
Indentation Hardness ◽  
Indentation Modulus ◽  
Maximum Hardness ◽  
New Material ◽  
Butadiene Styrene

This paper analyzes the indentation hardness and the indentation elastic modulus variation depending on the variation of the grind percentage of polymer, when the other factors that can influence the injection molding remain unchanged. The analyzed polymers were: acrylonitrile butadiene styrene ABS MAGNUM 3453, polyamide PA 6.6 TECHNYL AR218V30 Blak and polyoxymethylene POM EUROTAL C9 NAT. The samples that were studied had different compositions in new and grinding material. The G-Series Basic Hardness Modulus at a Depth method was used. The increase of the grind percentage of ABS (from 0 to 100 %) leads to insignificant changes in the indentation hardness, indentation modulus, and maximum force applied to samples of tested material. The maximum hardness (0.137 GPa) of PA 6.6 is recorded in the case of the sample with 80% grind content, and the maximum hardness of POM is recorded as well in the case of the sample with 80% grind content, as being 0.215 GPa. The variation of the grind content in the analyzed samples determines changes in the evaluated parameters, depending on the type of polymer. Combining the new material with grind in proportions experimentally established for each techno polymer leads to changes in their mechanical properties.

scholarly journals Repair Adhesive Strength of Conventional and Bulk Fill Resins Using Different Bonding Techniques

2021 ◽  
Vol 22 (3) ◽  
pp. 185-190
Author(s):  
Wilian Segatto Zanelli ◽  
Mariana Dias Flor-Ribeiro ◽  
Rodrigo Barros Esteves ◽  
Luís Roberto Marcondes Martins ◽  
Flávio Henrique Baggio Aguiar ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Adhesive System ◽  
Composite Resins ◽  
The Other ◽  
Adhesive Systems ◽  
Mean Values ◽  
Normality Test ◽  
Point Test

AbstractThis research aimed to evaluate the bond strength by micro tensile strength (µTBS), elastic modulus (EM) and flexural strength (FS) by the three-point test using three types of composite resins: Charisma Diamond, Filtek Z350 and Tetric N-Ceram Bulk Fill; and three adhesion techniques: adhesive, silane, silane and adhesive. The combinations of each resin with the adhesive technique resulted in nine groups (n = 12). Initially, with the composites, EM and FS tests were performed. Sequentially, each fragment was repaired with the different adhesive systems. All samples were subjected to µTBS testing on a universal assay machine. Data were subjected to the normality test and the parametric ANOVA test. Charisma resin showed the highest values in EM and RF compared to the other composite resins (p <0.05). The highest µTBS value was for silane + adhesive repaired Charisma resin. The lowest µTBS values were in Bulk Fill resin, regardless of adhesive system. The EM and FS results showed that Filtek Z350 resins had the best results, while bulk fill resins had lower results. It was concluded that Charisma and Filtek Z350 resins presented better results. However, in the bulk fill group, the lowest mean values of µTBS, FS and EM were obtained, as well as the lowest value in EM.Keywords: Composite Resins. Adhesives. Flexural Strength.ResumoEsta pesquisa teve como objetivo avaliar a resistência de união (RU) por resistência à microtração, módulo de elasticidade (ME) e resistência à flexão (RF) pelo teste de três pontos, utilizando três tipos de resinas compostas: Charisma Diamond, Filtek Z350 e Tetric N-Ceram Bulk Fill; e três técnicas de adesão: adesivo, silano, silano e adesivo. As combinações de cada resina com a técnica adesiva resultaram nove grupos (n= 12). Inicialmente, com os compósitos foram realizados testes de ME e RF. Sequencialmente, cada fragmento foi reparado com os diferentes sistemas adesivos. Todas as amostras foram submetidas ao teste de RU por microtração em uma máquina de ensaio universal. Os dados foram submetidos ao teste de normalidade e ao teste paramétrico ANOVA. A resina Charisma apresentou os maiores valores no ME e RF em relação às demais resinas compostas (p <0,05). O maior valor de RU foi para a resina Charisma reparada com silano + adesivo. Os menores valores de RU foram na resina Bulk Fill, independentemente do sistema adesivo. Os resultados no ME e RF mostraram que as resinas Filtek Z350 obtiveram os melhores resultados, enquanto as resinas bulk fill obtiveram resultados inferiores. Conclui-se que as resinas Charisma e Filtek Z350 apresentaram melhores resultados. Entretanto, no grupo de bulk fill obteve se as menores médias de RU, RF e ME, bem como o menor valor no ME.Palavras-chave: Resinas Compostas. Adesivos. Resistência à Flexão.

scholarly journals Effect of Camphorquinone Concentration in Physical-Mechanical Properties of Experimental Flowable Resin Composites

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Dayany da Silva Alves Maciel ◽  
Arnaldo Bonfim Caires-Filho ◽  
Marta Fernandez-Garcia ◽  
Camillo Anauate-Netto ◽  
Roberta Caroline Bruschi Alonso
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Mechanical Strength ◽  
Surface Hardness ◽  
Degree Of Conversion ◽  
Bending Test ◽  
Resin Matrix ◽  
Shrinkage Stress ◽  
Depth Of Cure

The aim of this study was to evaluate the effect of camphorquinone concentration in physical-mechanical properties of experimental flowable composites in order to find the concentration that results in maximum conversion, balanced mechanical strength, and minimum shrinkage stress. Model composites based on BISGMA/TEGDMA with 70% wt filler loading were prepared containing different concentrations of camphorquinone (CQ) on resin matrix (0.25%, 0.50%, 1%, 1.50%, and 2% by weight). Degree of conversion was determined by FTIR. Surface hardness was assessed before and after 24 h ethanol storage and softening rate was determined. Depth of cure was determined by Knoop hardness evaluation at different depths. Color was assessed by reflectance spectrophotometer, employing the CIE-Lab system. Flexural strength and elastic modulus were determined by a three-point bending test. Shrinkage stress was determined in a Universal Testing Machine in a high compliance system. Data were submitted to ANOVA and Tukey’s test (α = 0.05). The increase in CQ concentration caused a significant increase on flexural strength and luminosity of composites. Surface hardness was not affected by the concentration of CQ. Composite containing 0.25% wt CQ showed lower elastic modulus and shrinkage stress when compared to others. Depth of cure was 3 mm for composite containing 1% CQ and 2 mm for the other tested composites. Degree of conversion was inversely correlated with softening rate and directly correlated with elastic modulus and shrinkage stress. In conclusion, CQ concentration affects polymerization characteristics and mechanical strength of composites. The concentration of CQ in flowable composite for optimized polymerization and properties was 1% wt of the resin matrix, which allows adequate balance among degree of conversion, depth of cure, mechanical properties, and color characteristics of these materials.

scholarly journals Polymerization Behavior and Mechanical Properties of High-Viscosity Bulk Fill and Low Shrinkage Resin Composites

2017 ◽  
Vol 42 (6) ◽  
pp. E177-E187 ◽  
Author(s):  
S Shibasaki ◽  
T Takamizawa ◽  
K Nojiri ◽  
A Imai ◽  
A Tsujimoto ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Resin Composite ◽  
High Viscosity ◽  
The Other ◽  
Light Irradiation ◽  
Volumetric Shrinkage ◽  
Resin Composites ◽  
Polymerization Shrinkage

SUMMARY The present study determined the mechanical properties and volumetric polymerization shrinkage of different categories of resin composite. Three high viscosity bulk fill resin composites were tested: Tetric EvoCeram Bulk Fill (TB, Ivoclar Vivadent), Filtek Bulk Fill posterior restorative (FB, 3M ESPE), and Sonic Fill (SF, Kerr Corp). Two low-shrinkage resin composites, Kalore (KL, GC Corp) and Filtek LS Posterior (LS, 3M ESPE), were used. Three conventional resin composites, Herculite Ultra (HU, Kerr Corp), Estelite ∑ Quick (EQ, Tokuyama Dental), and Filtek Supreme Ultra (SU, 3M ESPE), were used as comparison materials. Following ISO Specification 4049, six specimens for each resin composite were used to determine flexural strength, elastic modulus, and resilience. Volumetric polymerization shrinkage was determined using a water-filled dilatometer. Data were evaluated using analysis of variance followed by Tukey's honestly significant difference test (α=0.05). The flexural strength of the resin composites ranged from 115.4 to 148.1 MPa, the elastic modulus ranged from 5.6 to 13.4 GPa, and the resilience ranged from 0.70 to 1.0 MJ/m3. There were significant differences in flexural properties between the materials but no clear outliers. Volumetric changes as a function of time over a duration of 180 seconds depended on the type of resin composite. However, for all the resin composites, apart from LS, volumetric shrinkage began soon after the start of light irradiation, and a rapid decrease in volume during light irradiation followed by a slower decrease was observed. The low shrinkage resin composites KL and LS showed significantly lower volumetric shrinkage than the other tested materials at the measuring point of 180 seconds. In contrast, the three bulk fill resin composites showed higher volumetric change than the other resin composites. The findings from this study provide clinicians with valuable information regarding the mechanical properties and polymerization kinetics of these categories of current resin composite.

scholarly journals Novel Poly(Methyl Methacrylate) Containing Nanodiamond to Improve the Mechanical Properties and Fungal Resistance

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3438 ◽  
Author(s):  
Utkarsh Mangal ◽  
Ji-Yeong Kim ◽  
Ji-Young Seo ◽  
Jae-Sung Kwon ◽  
Sung-Hwan Choi
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Methyl Methacrylate ◽  
Vickers Hardness ◽  
Surface Hardness ◽  
Fungal Resistance ◽  
Control Group ◽  
Poly Methyl Methacrylate ◽  
Fungal Adhesion

Herein we evaluate the effect of nanodiamond (ND) incorporation on the mechanical properties of poly(methyl methacrylate) (PMMA) nanocomposite. Three quantities of ND (0.1, 0.3, and 0.5 wt.%) were tested against the control and zirconium oxide nanoparticles (ZrO). Flexural strength and elastic modulus were measured using a three-point bending test, surface hardness was evaluated using the Vickers hardness test, and surface roughness was evaluated using atomic force microscopy (AFM), while fungal adhesion and viability were studied using Candida albicans. Samples were also analyzed for biofilm thickness and biomass in a saliva-derived biofilm model. All groups of ND-PMMA nanocomposites had significantly greater mean flexural strengths and statistically improved elastic modulus, compared to the control and ZrO groups (P < 0.001). The Vickers hardness values significantly increased compared to the control group (P < 0.001) with 0.3% and 0.5% ND. ND addition also gave significant reduction in fungal adhesion and viability (P < 0.001) compared to the control group. Finally, salivary biofilm formation was markedly reduced compared to the ZrO group. Hence, the incorporation of 0.1–0.5 wt.% ND with auto- polymerized PMMA resin significantly improved the flexural strength, elastic modulus, and surface hardness, and provided considerable fungal resistance.

scholarly journals Assessment of the Effect of Acid and Base Cycling on Mechanical Properties of Various Esthetic Restorative Materials

2021 ◽  
pp. 31-38
Author(s):  
Horieh Moosavi ◽  
Fatemeh Rezaei ◽  
Zahra Rezaei ◽  
Zahra Soroush
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Control Group ◽  
Glass Ionomer ◽  
Resin Modified Glass Ionomer ◽  
Restorative Materials ◽  
Acid And Base ◽  
Ph Cycling ◽  
Restorative Composites

Objective: The purpose of this study is the evaluation of the effect of pH cycling, including both acidic and alkaline environments, on the mechanical properties of tooth-colored restorative materials. Methods and Materials: 20 rectangular bar specimens of one bulk-fill restorative composite, two conventional nanohybrid restorative composites, and one restorative resin-modified glass ionomer were produced according to ISO 4049. Half of the materials were stored in an acid and base cycling defined as two-day storage in acidic (pH =4) and alkaline (pH=8) solutions. The rest of the materials were incubated in distilled water as a control group. The storage lasted for 48 days. Finally, flexural strength, elastic modulus, and microhardness of the specimens in each group determined. Data analyzed with Kruskal-Wallis, Dunn, MANOVA, Tukey HSD and T-test.  Results: The pH cycling model had a significant influence on all mechanical properties of the bulk-fill restorative composite and resin-modified glass ionomer than those stored in water (P <0.05). One of the conventional nanohybrid restorative composites showed a significant reduction in elastic modulus and microhardness while the other one showed a significant reduction only in flexural strength.  Conclusion: pH cycling negatively affects the mechanical properties of resin composites, and the materials’ composition is an important factor in the degradation of the resin-based materials examined.

scholarly journals Effects on Hardness and Elastic Modulus for DSS-8 Peptide Treatment on Remineralization of Human Dental Tissues

2008 ◽  
Vol 1132 ◽  
Author(s):  
Chia-Chan Hsu ◽  
Hsiu-Ying Chung ◽  
Elizabeth Marie Hagerman ◽  
Wenyuan Shi ◽  
Jenn-Ming Yang ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Grazing Incidence ◽  
Variable Pressure ◽  
Tooth Remineralization ◽  
Force Microscopy ◽  
Dental Tissues ◽  
Atomic Force ◽  
Human Enamel ◽  
Demineralized Enamel ◽  
Tooth Surfaces

ABSTRACTDental remineralization may be achieved by mediating the interactions between tooth surfaces with free ions and biomimetic peptides. We recently developed octuplet repeats of aspartate-serine-serine (DSS-8) peptide, which occurs in high abundance in naturally occurring proteins that are critical for tooth remineralization. In this paper, we evaluated the possible role of DSS-8 in enamel remineralization. Human enamel specimens were demineralized, exposed briefly to DSS-8 solution, and then exposed to concentrated ionic solutions that favor remineralization. Enamel nano-mechanical behaviors, hardness and elastic modulus, at various stages of treatment were determined by nanoindentation. The phase, microstructure and morphology of the resultant surfaces were characterized using the grazing incidence X-ray diffraction (GIXD), variable pressure scanning electron microscopy (VPSEM), and atomic force microscopy (AFM), respectively. Nanoindentation results show that the DSS-8 remineralization effectively improves the mechanical and elastic properties for demineralized enamel.

scholarly journals Mechanical Properties of Experimental Composites with Different Photoinitiator

2021 ◽  
Author(s):  
Luis Felipe Marques de Resende ◽  
Anderson Catelan ◽  
Kusai Baroudi ◽  
Alan Rodrigo Muniz Palialol ◽  
Alexandre Marques de Resende ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Phosphine Oxide ◽  
Light Emitting Diode ◽  
Surface Hardness ◽  
Triethylene Glycol ◽  
Bottom Surface ◽  
Significance Level ◽  
Depth Of Cure

Abstract Objective The effect of different photoinitiators on mechanical properties of experimental composites was evaluated. Materials and Methods Resin composites were formulated by using a blend of bisphenol A-glycidyl and triethylene glycol (50/50 wt%) dimethacrylate monomers, and 65 wt% of barium aluminium silicate and silica filler particles. Photoinitiators used were 0.2% camphorquinone (CQ) and 0.8% co-initiator (DMAEMA); 0.2% phenyl-propanedione and 0.8% DMAEMA; 0.1% CQ + 0.1% phenyl propanedione and 0.8% DMAEMA; 0.42% mono(acyl)phosphine oxide (MAPO); and 0.5% bis(acyl)phosphine oxide (BAPO). Specimens (n = 10) were light cured by using a multiple-emission peak light-emitting diode for 20 seconds at 1,200 mW/cm2 of irradiance and Knoop hardness and plasticization, depth of cure, flexural strength, and elastic modulus were evaluated. Data were statiscally analyzed at significance level of α = 5%. Results Experimental composites containing MAPO and BAPO photoinitiators showed the highest values of flexural strength, elastic modulus, top surface hardness, and lower hardness reduction caused by alcohol compared with CQ. Composites containing CQ and PPD showed similar results, except for depth of cure and hardness of bottom surface. Conclusion BAPO and MAPO showed higher flexural strength, elastic modulus, hardness on top surface, and lower polymer plasticization to CQ.

Flexural Properties of Bioactive Restoratives in Cariogenic Environments

2021 ◽  
Author(s):  
AU Yap ◽  
HS Choo ◽  
HY Choo ◽  
NA Yahya
Keyword(s):  
Flexural Strength ◽  
Mechanical Performance ◽  
Flexural Modulus ◽  
Flexural Properties ◽  
Glass Ionomer ◽  
Bioactive Materials ◽  
Flexural Testing ◽  
Resin Modified Glass Ionomer ◽  
Ph Cycling ◽  
Acidic Conditions

Clinical Relevance The strength of some bioactive materials can be compromised by cariogenic challenges. This may impact the clinical longevity of restorations, especially in stress-bearing areas. SUMMARY This study determined the mechanical performance of bioactive restoratives in cariogenic environments and compared the flexural properties of various bioactive materials. The materials evaluated included a conventional resin-based composite (Filtek Z350 [FZ]) and 3 bioactive restoratives, namely an alkasite (Cention N [CN]), a giomer (Beautifil-bulk Restorative [BB]), and an enhanced resin-modified glass ionomer (Activa Bioactive Restorative [AV]). Beam-shaped specimens (12 x 2 x 2 mm) were produced, randomly allocated to 4 groups (n=10), and conditioned in deionized solution, remineralizing solution, demineralizing solution (DE), or pH cycled for 14 days at 37°C. After conditioning/pH cycling, the specimens were subjected to 3-point flexural testing. Flexural data were subjected to statistical analysis using analysis of variance or Tukey’s test (α=0.05). Mean flexural modulus and strength ranged from 3.54 ± 0.33 to 7.44 ± 0.28 GPa, and 87.07 ± 8.99 to 123.54 ± 12.37 MPa, respectively. While the flexural modulus of the bioactive restoratives was not affected by cariogenic/acidic conditions, flexural strength usually decreased, with the exception of CN. The strength of BB was significantly reduced by DE and pH cycling, while that of AV was lowered by DE. For all conditioning mediums, AV had a significantly lower modulus than the other materials. Apart from conditioning in DE, where differences in flexural strength was insignificant, FZ and AV were generally significantly stronger than BB and CN. The effect of cariogenic environments on flexural strength was found to be material dependent, and aside from the alkasite material (CN), cariogenic conditions were observed to significantly decrease the strength of bioactive restoratives.

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