Análisis cuantitativo de Streptococcus mutans y Candida albicans en resinas compuestas para uso en bases protésicas (estudio in vitro)

[13:37, 17/12/2021] Doctor Ulises: Objetivo: El objetivo de esta investigación fue determinar el efecto antimicrobiano de PMMA (termo polimerizable y auto polimerizable) modificados con nanopartículas de plata (AgNPs) mediante cultivos bacterianos. Material y Métodos: AGNPs con un tamaño promedio de 15-20nm diluidas en alcohol metílico se añadieron al polímero de cuatro tipos de PMMA en una proporción de 12.5gr./ polímero por 1.25ml/AGNPs. Un total de 64 muestras fueron elaboradas y separadas en ocho grupos; por otra parte, Enterococcus faecalis y Streptococcus mutans fueron cultivados de manera independiente utilizando medio de cultivo semisólido de agar tripticaseína de soya (TSA); en la prueba de adhesión microbiana se colocaron 4 muestras de cada grupo en cajas Petri cultivadas de manera independiente para cada microorganismo. Resultados: Las muestras pertenecientes a los grupos: GII PMMA Nic Tone® Termo curable conAgNPs, GIV PMMA Arias® Termocurable con AgNPs, GVI PMMA Nic Tone® Termo curable y GVIII PMMA Arias® Termocurable presentaron una superficie más tersa al pulido; las muestras Autocurables del grupo Experimental GI PMMA Arias® Auto curable con AgNPs y GIII PMMA Nic Tone® Autocurable con AgNPs; las pruebas microbiológicas evidenciaron una baja inhibición bacteriana con respecto a la formación de halos ante los dos microorganismos utilizados en esta prueba (E. faecalis y C. albicans), sin embargo, se destaca que a 48 horas de incubación no hubo crecimiento alrededor ni sobre la superficie en los siguientes grupos: GI PMMA Arias® Auto [13:38, 17/12/2021] Doctor Ulises: curable con AgNPs, GII PMMA Nic Tone® Termo curable conAgNPs, GIII PMMA Nic Tone® Autocurable con AgNPs, y GIV PMMA Arias® Termocurable con AgNPs. Conclusiones: Los hallazgos de este estudio preliminar demostraron la mayor inhibición de microorganismos en el grupo GIII, esto sugiere que la modificación al PMMA con AgNPs es exitosa en diversos tipos de materiales existentes en el mercado odontológico, adicionalmente se observó potencial de inhibición sobre C. albicans y E. faecalis, microorganismos considerados como patógenos, lo que podría ayudar en la prevención de estomatitis bacteriana

Silver nanoparticles in orthodontics, a new alternative in bacterial inhibition: in vitro study

Background The purpose of the study is to assess the antiadherent and antibacterial properties of surface-modified different orthodontic brackets with silver nanoparticles against Streptococcus mutans and Streptococcus sobrinus, using radiomarker. Methods In this study evaluated quantitatively the adherence of Streptococci to orthodontic brackets, 300 samples of orthodontic brackets were selected and classified in to 10 groups as follow: GIn (InVu-Roth), GIIn (System-AlexanderLTS), GIIIn (Gemini-Roth), GIVn (NuEdge-Roth), GVn (Radiance plus-Roth), GVI (InVu-Roth), GVII (System-AlexanderLTS), GVIII (Gemini-Roth), GIX (NuEdge-Roth), GX (Radiance plus-Roth). All the samples were sonicated and Streptococci were cultivated by gender. A radioactive marker (3H) was used to codify the bacteria and measure them. After that, the brackets were submerged in a radiolabelled solution, and the radiation was measured. The statistical analysis was calculated with ANOVA test (Sheffè post hoc). Results The results showed significant differences were found among the groups. GIIIn shown the lowest scores for both bacteria; in contrast, GIX for Streptococcus mutans and GVI for Streptococcus sobrinus were the highest values. Conclusions Surface modification of orthodontic brackets with silver nanoparticles can be used to prevent the accumulation of dental plaque and the development of dental caries during orthodontic treatment

Quantitative analysis of S. mutans and S. sobrinus cultivated independently and adhered to polished orthodontic composite resins

In Orthodontics, fixed appliances placed in the oral cavity are colonized by microorganisms. OBJECTIVE: The purpose of this study was to quantitatively determine the independent bacterial colonization of S. mutans and S. sobrinus in orthodontic composite resins. MATERIAL AND METHODS: Seven orthodontic composite adhesives for bonding brackets were selected and classified into 14 groups; (GIm, GIs) Enlight, (GIIm, GIIs) Grengloo, (GIIIm, GIIIs) Kurasper F, (GIVm, GIVs) BeautyOrtho Bond, (GVm, GVs) Transbond CC, (GVIm, GVIs) Turbo Bond II, (GVIIm, GVIIs) Blugloo. 60 blocks of 4x4x1 mm of each orthodontic composite resin were made (total 420 blocks), and gently polished with sand-paper and ultrasonically cleaned. S. mutans and S. sobrinus were independently cultivated. For the quantitative analysis, a radioactive marker was used to codify the bacteria (³H) adhered to the surface of the materials. The blocks were submerged in a solution with microorganisms previously radiolabeled and separated (210 blocks for S. mutans and 210 blocks for S. sobrinus) for 2 hours at 37ºC. Next, the blocks were placed in a combustion system, to capture the residues and measure the radiation. The statistical analysis was calculated with the ANOVA test (Sheffè post-hoc). RESULTS: Significant differences of bacterial adhesion were found amongst the groups. In the GIm and GIs the significant lowest scores for both microorganisms were shown; in contrast, the values of GVII for both bacteria were significantly the highest. CONCLUSIONS: This study showed that the orthodontic composite resin evaluated in the GIm and GIs, obtained the lowest adherence of S. mutans and S. sobrinus, which may reduce the enamel demineralization and the risk of white spot lesion formation

Synthesis and Characterization of Silver Nanoparticles on Orthodontic Brackets: A New Alternative in the Prevention of White Spots

Abstract: Silver nanoparticles (AgNPs) are used for their powerful antibacterial e ect and their ability to adhere to surfaces due to their size; they are used in di erent areas of life, mainly in the area of health as medicine. More recently, in dentistry, the synthesis and characterization of AgNPs attracted significant attention due to their antibacterial properties. In this study, the AgNPs were synthesized using the most e ective method on di erent orthodontic brackets (metallic and esthetic) and characterized by scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS) and transmission electron microscopy (TEM). Their antimicrobial e ect was tested against the widely used standard human pathogens Staphylococcus aureus (Gram-negative) and Escherichia coli (Gram-positive). Our results showed that, via a simple chemical method, AgNPs can be synthesized on the surface of orthodontic brackets with good antimicrobial activity and the possibility of reducing dental decay, periodontal disease and white spots generated during orthodontic treatment

Green Synthesis of Silver Nanoparticles Using Heterotheca inuloides and Its Antimicrobial Activity in Catgut Suture Threads

Abstract Silver nanoparticles were synthesized through a green method, using Heterotheca inuloides as a bioreducing agent. Moreover, catgut suture threads were decorated with those biogenic silver nanoparticles, and their antibacterial activity versus highly resistant pathogenic microorganisms was evaluated. The principles of green chemistry and nanotechnology allow us to obtain advanced materials, such as suture threads, which can reduce or avoid the prevalence of infectious processes in the medical field. Mexican medicinal plants, such as H. inuloides, represent an adequate alternative for biosynthesis; this plant species is known for its medicinal benefits and its antibacterial activity, and for that reason, it is being used in folk medicine

Green Synthesis of Silver Nanoparticles Using <em>Heterotheca inuloides</em> and Its Antimicrobial Activity in Catgut Suture Threads

Silver nanoparticles were synthesized through a green method, using Heterotheca inuloides as a bioreducing agent. Moreover, catgut suture threads were decorated with those biogenic silver nanoparticles, and their antibacterial activity versus highly resistant pathogenic microorganisms was evaluated. The principles of green chemistry and nanotechnology allow us to obtain advanced materials, such as suture threads, which can reduce or avoid the prevalence of infectious processes in the medical field. Mexican medicinal plants, such as H. inuloides, represent an adequate alternative for biosynthesis; this plant species is known for its medicinal benefits and its antibacterial activity, and for that reason, it is being used in folk medicine

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Efecto de un cepillo dental eléctrico con pastas dentales blanqueadoras sobre la superficie del esmalte. Estudio in vitro

Existen pastas dentales altamente abrasivas, como lo son los dentífricos con efecto blanqueador, se estudiaron los efectos de estas pastas sobre la morfología de la superficie del esmalte de dientes de ganado bovino, los cuales se cepillaron por un lapso de seis meses. Se utilizó un Microscopio de Fuerza Atómica para observar y analizar los cambios morfológicos después del cepillado, concluyendo en que existen cambios significativos. Considerando que existen pacientes que utilizan este tipo de dentífricos como pasta de uso convencional, es importante considerar que pueden causar, a largo plazo, desgaste o cambios en la morfología de los dientes

ADHESION OF Candida albicans AND Streptococcus mutans TO SILVER NANOPARTICLE-MODIFIED POLYMETHYLMETHACRYLATE

"This in vitro study independently evaluated the adhesion of Candida albicans (ATCC 18804) and Streptococcus mutans (ATCC 25175) to polymethylmethacrylate (PMMA) blocks modified with silver nanoparticles (AgNPs). A total of 160 samples were used, separat