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2.
Medwave ; 20(7): e8003, 2020 Aug 25.
Artículo en Español, Inglés | MEDLINE | ID: mdl-32877393

RESUMEN

INTRODUCTION: Cavitated carious lesions in primary and mixed dentition require prompt treatment to control caries progression. Silver diamine fluoride has emerged as an alternative to the atraumatic restorative technique due to its easy application. However, there is still uncertainty regarding its effectiveness and safety. METHODS: We searched in Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a metanalysis and generated a summary of findings table using the GRADE approach. RESULTS AND CONCLUSIONS: We identified ten systematic reviews, including two studies overall, which are randomized trials. We concluded that silver diamine fluoride compared to the atraumatic restorative technique may increase the arrest of caries in primary and mixed first phase dentition, however, the certainty of the evidence has been assessed as low. On the other hand, treatment with silver diamine fluoride compared to the atraumatic restorative technique (ART) probably increases the risk of adverse events.


INTRODUCCIÓN: Las lesiones de caries cavitadas en dentición primaria y mixta requieren un tratamiento oportuno, para evitar así la progresión de la caries. El fluoruro diamino de plata ha surgido como una alternativa a la técnica de restauración atraumática debido a su fácil aplicación. Sin embargo, aún existe incertidumbre en relación a su efectividad y seguridad. MÉTODOS: Realizamos una búsqueda en Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante el cribado de múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, analizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES: Identificamos diez revisiones sistemáticas que en conjunto incluyeron dos estudios primarios, ambos ensayos aleatorizados. Concluimos que el fluoruro diamino de plata en comparación a la técnica de restauración atraumática podría aumentar el arresto de caries en dentición primaria y mixta primera fase, pero la certeza de la evidencia ha sido evaluada como baja. Por otra parte, el tratamiento con fluoruro diamino de plata comparado con la técnica de restauración atraumática (ART) probablemente aumenta el riesgo de eventos adversos.


Asunto(s)
Tratamiento Restaurativo Atraumático Dental/métodos , Caries Dental/prevención & control , Compuestos de Amonio Cuaternario/administración & dosificación , Compuestos de Plata/administración & dosificación , Cariostáticos/administración & dosificación , Cariostáticos/efectos adversos , Bases de Datos Factuales , Dentición Mixta , Fluoruros Tópicos/administración & dosificación , Fluoruros Tópicos/efectos adversos , Humanos , Compuestos de Amonio Cuaternario/efectos adversos , Ensayos Clínicos Controlados Aleatorios como Asunto , Compuestos de Plata/efectos adversos
4.
Mater Sci Eng C Mater Biol Appl ; 108: 110405, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31923947

RESUMEN

The number of studies on microcrystals containing silver has increased in recent decades. Among the silver-containing microcrystals, α-AgVO3 has gained prominence owing to its polymorphism that allows it to exert interesting antimicrobial activity against pathogenic microorganisms. The aim of this study was to evaluate the antifungal activity and cytotoxicity of three different α-AgVO3 microcrystals when in solution. α-AgVO3 microcrystals were synthesized using the co-precipitation method at three different temperatures (10 °C, 20 °C, and 30 °C), and then characterized by X-ray diffraction and scanning electron microscopy. The antifungal activity of α-AgVO3 microcrystals against Candida albicans was determined by estimating the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). Fluorescence images were obtained to confirm antifungal concentrations. To assess the biocompatibility of microcrystals applied at MIC and MFC on keratinocytes cells (NOK-si), an Alamar Blue assay, scanning electron microscopy, and a DNA gel integrity test were carried out. The quantitative and qualitative results showed that, regardless of the co-precipitation method used to synthetize α-AgVO3 microcrystals, C. albicans growth was visibly inhibited at 3.9 µg/mL (MIC) and completely inhibited at 15.62 µg/mL (MFC). The cytotoxic and genotoxic outcomes revealed that the MIC and MFC concentrations did not affect NOK-si cell morphology, proliferation, or DNA integrity. The search for new antimicrobial materials has been the focus of the research community recently because of increases in microbial resistance. The findings reported herein demonstrate a novel antifungal and non-cytotoxic material that could be used in biomedical and dental applications.


Asunto(s)
Antifúngicos/farmacología , Candida albicans/efectos de los fármacos , Óxidos/farmacología , Compuestos de Plata/farmacología , Compuestos de Vanadio/farmacología , Antifúngicos/efectos adversos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Queratinocitos/efectos de los fármacos , Queratinocitos/metabolismo , Pruebas de Sensibilidad Microbiana , Microscopía Fluorescente , Óxidos/efectos adversos , Compuestos de Plata/efectos adversos , Compuestos de Vanadio/efectos adversos
5.
Medwave ; 20(7): e8003, 2020.
Artículo en Inglés, Español | LILACS | ID: biblio-1122677

RESUMEN

INTRODUCCIÓN: Las lesiones de caries cavitadas en dentición primaria y mixta requieren un tratamiento oportuno, para evitar así la progresión de la caries. El fluoruro diamino de plata ha surgido como una alternativa a la técnica de restauración atraumática debido a su fácil aplicación. Sin embargo, aún existe incertidumbre en relación a su efectividad y seguridad. MÉTODOS: Realizamos una búsqueda en Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante el cribado de múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, analizamos los datos de los estudios primarios, realizamos un metanálisis y preparamos una tabla de resumen de los resultados utilizando el método GRADE. RESULTADOS Y CONCLUSIONES: Identificamos diez revisiones sistemáticas que en conjunto incluyeron dos estudios primarios, ambos ensayos aleatorizados. Concluimos que el fluoruro diamino de plata en comparación a la técnica de restauración atraumática podría aumentar el arresto de caries en dentición primaria y mixta primera fase, pero la certeza de la evidencia ha sido evaluada como baja. Por otra parte, el tratamiento con fluoruro diamino de plata comparado con la técnica de restauración atraumática (ART) probablemente aumenta el riesgo de eventos adversos


INTRODUCTION: Cavitated carious lesions in primary and mixed dentition require prompt treatment to control caries progression. Silver diamine fluoride has emerged as an alternative to the atraumatic restorative technique due to its easy application. However, there is still uncertainty regarding its effectiveness and safety. METHODS: We searched in Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a metanalysis and generated a summary of findings table using the GRADE approach. RESULTS AND CONCLUSIONS: We identified ten systematic reviews, including two studies overall, which are randomized trials. We concluded that silver diamine fluoride compared to the atraumatic restorative technique may increase the arrest of caries in primary and mixed first phase dentition, however, the certainty of the evidence has been assessed as low. On the other hand, treatment with silver diamine fluoride compared to the atraumatic restorative technique (ART) probably increases the risk of adverse events.


Asunto(s)
Humanos , Compuestos de Plata/administración & dosificación , Caries Dental/prevención & control , Tratamiento Restaurativo Atraumático Dental/métodos , Compuestos de Amonio Cuaternario/administración & dosificación , Cariostáticos/administración & dosificación , Cariostáticos/efectos adversos , Ensayos Clínicos Controlados Aleatorios como Asunto , Fluoruros Tópicos/administración & dosificación , Fluoruros Tópicos/efectos adversos , Bases de Datos Factuales , Compuestos de Plata/efectos adversos , Dentición Mixta , Compuestos de Amonio Cuaternario/efectos adversos
6.
Compend Contin Educ Dent ; 40(3): 158-163; quiz 164, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30829497

RESUMEN

The use of silver diamine fluoride (SDF) for management of dental caries has gained considerable attention due to recent regulatory clearance in the United States. The primary focus of policies, presentations, and publications has been the arrest of caries lesions (cavities) because of the material's unique ability to non-invasively achieve this elusive and clinically important goal. However, SDF also has proven efficacy in prevention, ie, decreasing the incidence of new caries lesions. Analysis of nine clinical trials in children shows that SDF prevented 61% of new lesions compared to controls. To prevent one new caries lesion, clinicians need to treat four primary teeth (one patient) or 12.1 permanent molars (three patients) with SDF. The preventive effect appears to be immediate and maintains at the same fraction over time. Direct comparisons of SDF applied once per year with alternative treatments show that SDF is more effective than other topical fluorides placed two to four times per year and more cost-effective than dental sealants. Enamel lesions may be even more responsive than cavitated dentin lesions. Annual application of SDF to high-risk surfaces (eg, mesial surfaces of permanent first molars where the distal surface of the second primary molar is carious) in patients with any risk of new caries lesions appears to be the most cost-effective approach available to prevent dental caries. SDF is an underutilized evidence-based preventive agent for dental caries.


Asunto(s)
Caries Dental/prevención & control , Compuestos de Amonio Cuaternario/uso terapéutico , Compuestos de Plata/uso terapéutico , Niño , Análisis Costo-Beneficio , Caries Dental/historia , Fluoruros Tópicos/efectos adversos , Fluoruros Tópicos/historia , Fluoruros Tópicos/uso terapéutico , Historia del Siglo XX , Humanos , Compuestos de Amonio Cuaternario/efectos adversos , Compuestos de Amonio Cuaternario/historia , Compuestos de Plata/efectos adversos , Compuestos de Plata/historia
7.
Caries Res ; 53(1): 24-32, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-29874642

RESUMEN

OBJECTIVES: To investigate whether silver diamine fluoride (SDF) is effective in preventing new caries lesions in primary teeth when compared to placebo or active treatments. METHODS: Systematic review (CRD42016036963) of controlled clinical trials. Searches were performed in 9 electronic databases, 5 registers of ongoing trials, and reference lists of identified review articles. Two researchers carried out data extraction and quality appraisal independently. The primary outcome was the difference in caries increment (decayed, missing, and filled surfaces or teeth - dmfs or dmft) between SDF and control groups. These differences were pooled as weighted mean differences (WMD) and prevented fractions (PF). RESULTS: Searches yielded 2,366 unique records; 6 reports of 4 trials that randomized 1,118 and analyzed 915 participants were included. Two trials compared SDF to no treatment, 1 compared SDF to placebo and sodium fluoride varnish (FV), and 1 compared SDF to high-viscosity glass ionomer cement (GIC). All studies had at least 1 domain with unclear or high risk of bias. After 24 months of follow-up, in comparison to placebo, no treatment, and FV, SDF applications significantly reduced the development of new dentin caries lesions (placebo or no treatment: WMD = -1.15, PF = 77.5%; FV: WMD = -0.43, PF = 54.0%). GIC was more effective than SDF after 12 months of follow-up but the difference between them was not statistically significant (WMD, dmft: 0.34, PF: -6.09%). CONCLUSION: When applied to caries lesions in primary teeth, SDF compared to no treatment, placebo or FV appears to effectively prevent dental caries in the entire dentition. However, trials specifically designed to assess this outcome are needed.


Asunto(s)
Cariostáticos/uso terapéutico , Caries Dental/tratamiento farmacológico , Caries Dental/prevención & control , Compuestos de Amonio Cuaternario/uso terapéutico , Compuestos de Plata/uso terapéutico , Diente Primario/fisiología , Cariostáticos/efectos adversos , Niño , Preescolar , Ensayos Clínicos Controlados como Asunto , Fluoruros Tópicos/efectos adversos , Fluoruros Tópicos/uso terapéutico , Estudios de Seguimiento , Cementos de Ionómero Vítreo/efectos adversos , Cementos de Ionómero Vítreo/uso terapéutico , Humanos , Inflamación/etiología , Compuestos de Amonio Cuaternario/efectos adversos , Compuestos de Plata/efectos adversos , Fluoruro de Sodio/efectos adversos , Fluoruro de Sodio/uso terapéutico , Trastornos del Gusto/etiología , Decoloración de Dientes/etiología
8.
Dent Clin North Am ; 63(1): 45-68, 2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-30447792

RESUMEN

This article reviews current evidence on the effectiveness of silver diamine fluoride (SDF) as a caries arresting and preventive agent. It provides clinical recommendations around SDF's appropriate use as part of a comprehensive caries management program. Systematic reviews confirm that SDF is effective for caries arrest on cavitated lesions in primary teeth and root caries in the elderly. It may also prevent new lesions. Application is easy, noninvasive, affordable, and safe. Although it stains the lesions dark as it arrests them, it provides clinicians with an additional tool for caries management when esthetics are not a primary concern.


Asunto(s)
Cariostáticos/uso terapéutico , Caries Dental/prevención & control , Odontología Basada en la Evidencia , Compuestos de Amonio Cuaternario/uso terapéutico , Compuestos de Plata/uso terapéutico , Anciano , Antibacterianos/uso terapéutico , Niño , Fluoruros Tópicos/efectos adversos , Fluoruros Tópicos/uso terapéutico , Humanos , Satisfacción del Paciente , Odontología Pediátrica , Compuestos de Amonio Cuaternario/efectos adversos , Caries Radicular/prevención & control , Compuestos de Plata/efectos adversos , Remineralización Dental , Diente Primario
9.
Eur Arch Paediatr Dent ; 19(4): 221-227, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-30094547

RESUMEN

AIMS: Recently, there has been interest in biological approaches for caries management, with techniques such as interim therapeutic restorations and Hall technique crowns showing comparative effectiveness against conventional restorative methods. One of these approaches is the use of silver diamine fluoride (SDF) as a restorative option. In this invited review, the aim was to critically appraise the currently available literature with regards to the indication, technique and outcome of SDF. METHODS: A review of the literature on SDF with a focus on its use in the primary dentition was conducted. RESULTS: There has been a recent explosion in the literature regarding the use of SDF, from in vitro studies on the mechanism to clinical studies on the effectiveness and patient acceptance of the technique. A systematic review in 2016 concluded that SDF application resulted in caries arrest in 81% of active lesions in primary teeth over 30 months. Additionally, over 60% of parents reported being satisfied with the aesthetic outcome with most children finding the procedure to be acceptable, comfortable and relatively pain-free. CONCLUSIONS: Silver diamine fluoride is a safe and effective alternative technique to caries management in the paediatric population. Given the ongoing worldwide debate on cost-effectiveness of biological approaches coupled with the increasing concerns and limited accessibility of treatment under general analgesia, SDF should form an important addition to every dentist's armamentarium.


Asunto(s)
Cariostáticos/uso terapéutico , Caries Dental/tratamiento farmacológico , Compuestos de Amonio Cuaternario/uso terapéutico , Compuestos de Plata/uso terapéutico , Cariostáticos/efectos adversos , Niño , Contraindicaciones de los Medicamentos , Fluoruros Tópicos/efectos adversos , Fluoruros Tópicos/uso terapéutico , Humanos , Aceptación de la Atención de Salud , Compuestos de Amonio Cuaternario/efectos adversos , Compuestos de Plata/efectos adversos , Diente Primario
11.
J Dent Res ; 97(4): 395-401, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29237131

RESUMEN

This randomized clinical trial aimed to compare the adverse effects and parental satisfaction following the different regimes of silver diamine fluoride (SDF) treatment among preschool children. A total of 888 preschool children who had active dentin caries received different SDF application regimes: group 1, 12% SDF applied annually; group 2, 12% SDF applied semiannually; group 3, 38% SDF applied annually; and group 4, 38% SDF applied semiannually. Information on adverse effects-including tooth or gum pain, gum swelling, gum bleaching, and systemic toxicity-was collected through a parent-reported questionnaire within 1 wk after every SDF or placebo application. Information of parental satisfaction on children's dental appearance was collected at baseline and 30-mo examination. At the 30 mo, 799 children (90%) remained in the study. No acute systemic illness or major adverse effect was reported. No differences of all minor adverse effects among the 4 groups were found ( P > 0.05). Overall, prevalence of tooth and gum pain as perceived by patients and reported by parents was 6.6%, while gum swelling and gum bleaching were 2.8% and 4.7%, respectively. Blackening of carious lesions was common among all groups, with 36.7%, 49.5%, 65.6% and 76.3% in groups 1 to 4, respectively (χ2 test, P < 0.001). The proportion of parents who were satisfied with their children's dental appearance in groups 1 to 4 was as follows: 67.6%, 61.5%, 70.8%, and 62.3%, respectively (χ2 test, P > 0.05). Based on parental reporting, SDF does not cause acute systemic illness. Tooth or gum pain, gum swelling, and gum bleaching were uncommon and not significantly different among the study groups. Parental satisfaction with children's dental appearance was similar among all groups. The use of SDF following the study protocol for caries arrest is safe for preschool children. Collecting information on parental satisfaction and adverse effects is beneficial for dental professionals when deciding to adopt SDF treatment for preschool children (ClinicalTrials.gov NCT02385474).


Asunto(s)
Cariostáticos/efectos adversos , Caries Dental/prevención & control , Compuestos de Amonio Cuaternario/efectos adversos , Compuestos de Plata/efectos adversos , Preescolar , Femenino , Fluoruros Tópicos/efectos adversos , Hong Kong , Humanos , Masculino , Dimensión del Dolor , Encuestas y Cuestionarios , Diente Primario
13.
Gerodontology ; 34(3): 320-325, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28436056

RESUMEN

OBJECTIVES: This study evaluated the release of ions and the cytotoxicity of acrylic resins incorporated with silver vanadate decorated with silver nanoparticles (AgVO3 ). BACKGROUND: The inhibition of the accumulation of microorganisms on the resins is critical in preventing diseases. However, the hypothesis is that the release of ions from the incorporation of AgVO3 may be important in biocompatibility. MATERIALS AND METHODS: Specimens of autopolymerising (AP) and heat-polymerising resin (HP) with AgVO3 were prepared and immersed in culture medium. The release of silver ions (Ag) and vanadium (V) was evaluated by mass spectrometry with inductively coupled plasma (ICP-MS) (n=9) and the cell viability of fibroblasts L929 by MTT (3-[4,5-dimethylthiazol- 2yl]-2,5-diphenyltetrazolium bromide) (n=12). The results were evaluated with analysis of variance (ANOVA), Tukey and Pearson correlation test (α=.05). RESULTS: The groups containing AgVO3 presented a difference in relation to the control (0%) regarding the release of Ag and V (P<.0001). All groups showed a reduction in L929 viability when compared with the cellular control (100%) (P<.0001). In comparison with the control resins for HP, a reduction in the metabolism of cells occurred starting at 2.5% and for AP at 5% (P<.0001). A positive correlation was found between the concentration of AgVO3 and the ion release, and a negative between the ion release and the cell viability. CONCLUSIONS: Significant numbers of Ag and V ions were released from resins with higher concentrations of AgVO3 , presenting cytotoxicity for cells, suggesting that the use of low concentrations is indicated to avoid risks to patients.


Asunto(s)
Resinas Acrílicas/efectos adversos , Antiinfecciosos/efectos adversos , Nanopartículas del Metal/efectos adversos , Resinas Acrílicas/química , Animales , Antiinfecciosos/química , Línea Celular/efectos de los fármacos , Fibroblastos/efectos de los fármacos , Espectrometría de Masas , Nanopartículas del Metal/química , Ratones , Microscopía Electrónica de Rastreo , Compuestos de Plata/efectos adversos , Compuestos de Plata/química , Vanadatos/efectos adversos , Vanadatos/química
16.
Regul Toxicol Pharmacol ; 82: 157, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27825836

RESUMEN

Safety assessment is based on the release of silver ion from the packaging material. SCCS considers the release of silver ions from "EcoG+" as a component in packaging material safe for use as preservative with a concentration of maximum 2.0% in the cosmetic packaging material.


Asunto(s)
Seguridad de Productos para el Consumidor , Cosméticos/efectos adversos , Fosfatos/efectos adversos , Fosfatos/química , Conservadores Farmacéuticos/efectos adversos , Embalaje de Productos , Compuestos de Plata/efectos adversos , Pruebas de Toxicidad/métodos , Animales , Humanos , Medición de Riesgo
17.
Toxicology ; 363-364: 29-36, 2016 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-27427492

RESUMEN

Nanoscale particles have large surface to volume ratio that significantly enhances their chemical and biological reactivity. Although general toxicity of nano silver (nanoAg) has been intensively studied in both in vitro and in vivo models, its neurotoxic effects are poorly known, especially those of low-dose exposure. In the present study we assess whether oral administration of nanoAg influences behavior of exposed rats and induces changes in cerebral myelin. We examine the effect of prolonged exposure of adult rats to small (10nm) citrate-stabilized nanoAg particles at a low dose of 0.2mg/kg b.w. (as opposed to the ionic silver) in a comprehensive behavioral analysis. Myelin ultrastructure and the expression of myelin-specific proteins are also investigated. The present study reveals slight differences with respect to behavioral effects of Ag(+)- but not nanoAg-treated rats. A weak depressive effect and hyperalgesia were observed after Ag(+) exposure whereas administration of nanoAg was found to specifically increase body weight and body temperature of animals. Both nanoAg and Ag(+) induce morphological disturbances in myelin sheaths and alter the expression of myelin-specific proteins CNP, MAG and MOG. These results suggest that the CNS may be a target of low-level toxicity of nanoAg.


Asunto(s)
Cerebro/efectos de los fármacos , Nanopartículas del Metal/efectos adversos , Vaina de Mielina/efectos de los fármacos , Compuestos de Plata/efectos adversos , Animales , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Actividad Motora/efectos de los fármacos , Ratas , Ratas Wistar , Reconocimiento en Psicología/efectos de los fármacos , Prueba de Desempeño de Rotación con Aceleración Constante
19.
Med Phys ; 42(8): 4654-67, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26233193

RESUMEN

PURPOSE: The overall goal of this study is to restore kilovoltage computed tomography (kV-CT) images which are disfigured by patients' metal prostheses. By generating a hybrid sinogram that is a combination of kV and megavoltage (MV) projection data, the authors suggest a novel metal artifact-reduction (MAR) method that retains the image quality to match that of kV-CT and simultaneously restores the information of metal prostheses lost due to photon starvation. METHODS: CT projection data contain information about attenuation coefficients and the total length of the attenuation. By normalizing raw kV projections with their own total lengths of attenuation, mean attenuation projections were obtained. In the same manner, mean density projections of MV-CT were obtained by the normalization of MV projections resulting from the forward projection of density-calibrated MV-CT images with the geometric parameters of the kV-CT device. To generate the hybrid sinogram, metal-affected signals of the kV sinogram were identified and replaced by the corresponding signals of the MV sinogram following a density calibration step with kV data. Filtered backprojection was implemented to reconstruct the hybrid CT image. To validate the authors' approach, they simulated four different scenarios for three heads and one pelvis using metallic rod inserts within a cylindrical phantom. Five inserts describing human body elements were also included in the phantom. The authors compared the image qualities among the kV, MV, and hybrid CT images by measuring the contrast-to-noise ratio (CNR), the signal-to-noise ratio (SNR), the densities of all inserts, and the spatial resolution. In addition, the MAR performance was compared among three existing MAR methods and the authors' hybrid method. Finally, for clinical trials, the authors produced hybrid images of three patients having dental metal prostheses to compare their MAR performances with those of the kV, MV, and three existing MAR methods. RESULTS: The authors compared the image quality and MAR performance of the hybrid method with those of other imaging modalities and the three MAR methods, respectively. The total measured mean of the CNR (SNR) values for the nonmetal inserts was determined to be 14.3 (35.3), 15.3 (37.8), and 25.5 (64.3) for the kV, MV, and hybrid images, respectively, and the spatial resolutions of the hybrid images were similar to those of the kV images. The measured densities of the metal and nonmetal inserts in the hybrid images were in good agreement with their true densities, except in cases of extremely low densities, such as air and lung. Using the hybrid method, major streak artifacts were suitably removed and no secondary artifacts were introduced in the resultant image. In clinical trials, the authors verified that kV and MV projections were successfully combined and turned into the resultant hybrid image with high image contrast, accurate metal information, and few metal artifacts. The hybrid method also outperformed the three existing MAR methods with regard to metal information restoration and secondary artifact prevention. CONCLUSIONS: The authors have shown that the hybrid method can restore the overall image quality of kV-CT disfigured by severe metal artifacts and restore the information of metal prostheses lost due to photon starvation. The hybrid images may allow for the improved delineation of structures of interest and accurate dose calculations for radiation treatment planning for patients with metal prostheses.


Asunto(s)
Metales , Prótesis e Implantes , Tomografía/métodos , Artefactos , Calibración , Restauración Dental Permanente/efectos adversos , Cabeza , Humanos , Metales/efectos adversos , Modelos Biológicos , Pelvis , Fantasmas de Imagen , Polimetil Metacrilato , Prótesis e Implantes/efectos adversos , Compuestos de Plata/efectos adversos , Compuestos de Estaño/efectos adversos
20.
J Appl Toxicol ; 35(6): 631-9, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25645305

RESUMEN

This study was performed to understand how the choice of cytotoxicity assay format affects the observed biocompatibility of nanosilver (nAg). nAg coatings are physical coatings containing silver (Ag) that have feature sizes of 100 nm or less, often in the form of nanoparticles or grains. They are used on medical devices to prevent infection, but in spite of this intended benefit, observations of potential cytotoxicity from nAg have been reported in numerous published studies. For medical device regulation, cytotoxicity testing is part of a biocompatibility evaluation, in which specific test methods are chosen based on the technological characteristics and intended use of a device. For this study, nAg-coated tissue culture polystyrene surfaces were prepared using magnetron sputter coating, resulting in nAg films of 0.2 to 311 µg cm(-2) Ag. These coatings exhibited nanometer-scale morphologies and demonstrated a > 4log10 reduction in Escherichia coli viability. It was observed that extracts of nAg caused no cytotoxicity to L929 mouse fibroblasts, but cells cultured directly on nAg coatings (direct-contact assay format) showed a dose-dependent reduction in viability by up to 100% (P < 0.001). Results using inductively coupled plasma mass spectrometry to measure Ag release suggested that extracts of nAg are not toxic because the dissolved Ag in those samples becomes less cytotoxic over time, probably owing to the reaction with cell culture media and serum (six-fold cytotoxicity reductions observed over a 24-h period). These findings highlight the potential value of direct-contact cytotoxicity testing for nAg in predicting biological interactions with cells or tissue in vivo.


Asunto(s)
Antiinfecciosos/administración & dosificación , Fibroblastos/efectos de los fármacos , Nanopartículas del Metal/efectos adversos , Compuestos de Plata/efectos adversos , Animales , Antiinfecciosos/efectos adversos , Línea Celular , Supervivencia Celular/efectos de los fármacos , Materiales Biocompatibles Revestidos/administración & dosificación , Materiales Biocompatibles Revestidos/efectos adversos , Escherichia coli/efectos de los fármacos , Nanopartículas del Metal/administración & dosificación , Ratones , Compuestos de Plata/administración & dosificación , Pruebas de Toxicidad/métodos
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