Influence of microstructure and physical characteristics in the performance of non-professional masks sold in São Paulo.

OBJECTIVES: This study evaluates the performance of eight non-professional face masks sold in São Paulo, Brazil, to prevent aerial transmission of the SARS-CoV-2. STUDY DESIGN: This was a case report with comparative testing. METHODS: The masks manufactured with different materials and designs were quantified according to their performance to prevent COVID-19 using two indicators: filtration efficiency (FE) and differential pressure. The fabric grammage and microscopy of the layers were analyzed to understand their influence on the performance indicators. RESULTS: The results show no correlation between grammage in the FE and increasing grammage can compromise breathability indicator. Masks manufactured with cotton widely commercialized during the pandemic have non-uniformized results in FE indicators. CONCLUSIONS: There was no evidence between grammage and the number of layers in the FE indicator. The results pointed out that the layer's composition and the microstructure are the best way to evaluate the performance of non-professional masks used to prevent the aerial transmission of the SARS-CoV-2.

Avaliação do escoamento e extravasamento de cinco cimentos endodônticos através de radiografia digital: um estudo in vitro / Evaluation of flow and extravasation of five endodontic sealers through digital radiography: an in vitro study

Introdução: em Endodontia, a busca pelo sucesso clínico a longo prazo depende do conhecimento das propriedades de diversos materiais odontológicos. Objetivo: avaliar o escoamento e extravasamento de cimentos endodônticos em canais laterais fabricados em blocos de resina (IM do Brasil LTDA): Métodos: foram testados 5 cimentos utilizados em Endodontia (AH Plus®, Pulp Canal Sealer®, Endomethasone®, Sealer 26® e Endofill®). Para o estudo in vitro, utilizou-se 20 blocos transparentes de canais simulados, onde cada bloco possuía 3 canais: cervical, médio e apical. Resultados e Discussão: o Edomethasone® apresentou menor porcentagem de escoamento (66,67%) em relação aos demais. Em relação ao extravasamento, os canais cervicais dos grupos Endomethasone® (50%) e Endofill® (50%) foram os mais expressivos. Conclusão: todos os cimentos testados apresentaram bom escoamento e extravasamento para obturação do sistema de canais radiculares. O Pulp Canal Sealer® obteve maior porcentagem e média de escoamento, obturando os canais cervicais, médios e apicais. O Endomethasone® apresentou menor porcentagem de escoamento e o AH Plus®, a menor média de escoamento em milímetros quando avaliados os canais apicais. (AU)

Introduction: In Endodontics, the search for long-term clinical success depends on the knowledge of properties of several dental materials. Aim: To evaluate the flow and extravasation of endodontic sealers inside of channels made with resin blocks (IM Brazil LTDA). Five endodontic sealers were tested (AH Plus, Pulp Canal Sealer, Endomethasone, Sealer 26 and Endofill). Material and Methods: For the in vitro study, we used 20 transparent blocks of simulated channels, where each block had 3 channels: cervical, middle and apical. The Edomethasone sealer presented a smaller percentage of flow (66.67%) compared to the others. With regard to extravasation, cervical channels of Endomethasone (50%) and Endofill (50%) groups showed the highest percentage of extravasation. Conclusions: All tested endodontic sealers had good flow and extravasation. The Pulp Canal Sealer was the one that had the highest percentage of average flow. The sealer Endomethasone presented the lowest percentage of flow and AH Plus the lowest average flow in millimeters when evaluated apical channels. (AU)