5 results on '"Oliveira, Lucas Portela"'
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2. Influence of filling materials on the fracture resistance of resin composite used for sealing screw access hole
- Author
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PEREIRA, Rodrigo de Paula, primary, ROCHA, Cibele Oliveira de Melo, additional, JABR, Camila Luiz, additional, OLIVEIRA, Lucas Portela, additional, and ARIOLI FILHO, João Neudenir, additional
- Published
- 2022
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3. Synthesis, characterization of silver phosphate (Ag3PO4) and its action against Candida albicans associated with LED light
- Author
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Oliveira, Lucas Portela, Universidade Estadual Paulista (Unesp), and Vergani, Carlos Eduardo [UNESP]
- Subjects
Biofilms ,Candida albicans ,Fototerapia ,Phototherapy ,Antifúngicos ,Antifungal agents ,Biofilmes - Abstract
Submitted by Lucas Portela Oliveira (lucasportela2@gmail.com) on 2018-09-20T13:38:04Z No. of bitstreams: 1 Dissertação Lucas Portela.pdf: 4674713 bytes, checksum: 96eac4dbfd92488de3781cc70d2981e3 (MD5) Approved for entry into archive by Marley Cristina Chiusoli Montagnoli (marley@foar.unesp.br) on 2018-09-20T17:50:25Z (GMT) No. of bitstreams: 1 oliveira_lp_me_arafor.par.pdf: 311897 bytes, checksum: 62be83b6f5f0d6c0dc7e0b6c3e87d0a9 (MD5) Made available in DSpace on 2018-09-20T17:50:25Z (GMT). No. of bitstreams: 1 oliveira_lp_me_arafor.par.pdf: 311897 bytes, checksum: 62be83b6f5f0d6c0dc7e0b6c3e87d0a9 (MD5) Previous issue date: 2018-05-04 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Há diversas possibilidades para o controle microbiano, dentre elas, o uso de microcristais associados à prata (Ag), e a inativação fotodinâmica antimicrobiana (do inglês, aPDI). Devido à capacidade de fotoexcitação no comprimento de onda de luz azul, fosfato de prata (Ag3PO4) foi submetido à exposição a luz em 455nm. Este trabalho teve como objetivo sintetizar, caracterizar e verificar a capacidade fotocatalítica e antimicrobiana dos microcristais de Ag3PO4, utilizando culturas de C. albicans em suspensão e biofilme, na presença e ausência de luz. Os microcristais foram sintetizados pelo método da co-precipitação, e foram determinados o “gap” de energia e o espectro de absorção do material através de análise de espectro de UVVIS. Para caracterizar Ag3PO4, realizou-se a difração de raios-X (DRX), microscopia eletrônica de varredura por emissão de campo (MEV-EC) e atividade fotocatalítica (degradação de rodamina) após 4 exposições à luz. Para os ensaios microbiológicos (UFC/mL), determinou-se a concentração fungicida mínima (CFM) em suspensão e biofilme, na ausência e presença de luz (55,8 J/cm²). Para análise dos resultados, aplicou-se o teste de análise de variância de dois fatores, com teste posterior de Tukey. Os resultados demonstraram que o espectro de absorção abrange a faixa azul do comprimento de onda, apesar do maior sinal estar localizado na região de luz UV. Nos espectros de DRX observou-se a produção de prata cúbica e hexagonal no decorrer das exposições, juntamente com o aumento de material amorfo. Nas imagens de MEV-EC foi observado o tamanho dos microcristais (0,12 µm), os quais apresentaram morfologia arredondada, irregular e com natureza aglomerada, degradando-se após cada exposição à luz. Observou-se um aumento na atividade fotocatalítica de Ag3PO4, com aumento de velocidade na degradação do corante rodamina a cada novo ciclo. Nos testes microbiológicos em suspensão, as CFMs foram observadas (2000 e 250μg/mL) assim como em biofilme (4000 e 2000 μg/mL), na ausência e presença de luz, respectivamente. As imagens de MEV corroboraram com os dados de UFC/mL, no qual o microrganismo apresenta uma redução em seu crescimento ou deformação em sua morfologia quando comparada à sua forma arredondada padrão. Além disso, nas imagens de microscopia confocal à laser a quantidade de células mortas torna-se mais intensa à medida que as concentrações se aproximam da inibitória. Desta forma, através da síntese pelo método da coprecipitação, o microcristal de Ag3PO4 apresentou excelente atividade fotocatalítica em comprimento de onda de 455 nm, com potencialização da atividade antifúngica na presença de luz na faixa azul. There are several possibilities for microbial control, among them the use of microcrystals associated with silver (Ag), and antimicrobial photodynamic inactivation (aPDI). Due to the ability of photoexcitation in the blue light wavelength, silver phosphate (Ag3PO4) was subjected to light exposure at 455nm. Thus, the aim was to synthesize, characterize and verify the photocatalytic and antimicrobial capacity of Ag3PO4 microcrystals using cultures of C. albicans in planktonic and biofilm form, in the presence and absence of light. Microcrystals were synthesized by the coprecipitation method, the energy band gap and the absorption spectrum of the material were determined by UV-VIS spectrum analysis. To characterize Ag3PO4, Xray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and photocatalytic activity (rhodamine degradation) were performed after 4 exposures to light. For the microbiological tests (CFU/mL), the minimum fungicidal concentration (MFC) in planktonic and biofilm was determined, in the absence and presence of light (55.8 J/cm²). To analyze the results, a two-way analysis of variance (ANOVA) was applied, followed by Tukey post-test. The results showed the absorption spectrum covers the blue wavelength range, although the largest peak is located in the UV light region. The XRD spectra produced cubic and hexagonal silver during the exposures, with an increase of amorphous material. The microcrystal size was observed (0.12 μm) by FE-SEM images, with rounded and irregular morphology and agglomerated nature, degrading after each exposure to light. Besides, it was observed a gain in the photocatalytic activity of Ag3PO4, with an increasing rate of degradation on rhodamine dye at each new cycle. The MFCs were observed in the planktonic microbiological tests (2000 and 250 μg/mL) as well as in biofilm (4000 and 2000 μg/mL), in the absence and presence of light, respectively. FE-SEM images corroborated with CFU/mL data, showing a reduction on microorganism growth or deformation in its morphology when compared to its standard rounded form. Moreover, the number of dead cells in the confocal laser microscopy images becomes more intense with the approach of inhibitory concentration. Thus, through the co-precipitation method, the microcrystal of Ag3PO4 showed excellent photocatalytic activity at a 455nm wavelength, with potentiation of antifungal activity in the presence of light over blue band. 001
- Published
- 2018
4. Avaliação da performance mastigatória, força máxima em pacientes idososedentados reabilitados com dois tipos de próteses.
- Author
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FERREIRA, Gabriel Nogueira, JABR, Camila Luiz, OLIVEIRA, Lucas Portela, PERO, Ana Carolina, and ARIOLI FILHO, João Neudenir
- Abstract
Copyright of Universidade Estadual Paulista. Revista de Odontologia is the property of Universidade Estadual Paulista. Revista de Odontologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2023
5. Resistance to fracture of endodontically treated teeth: Influence of the post systems and cements.
- Author
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De Matos LMR, Oliveira LP, Silva AM, Silva JKA, and Silva ML
- Abstract
Background: Endodontically treated teeth with extensive structural damage present higher fragility due to the low amount and worse quality of the reminiscent tissues of the crown., Materials and Methods: The present in vitro study evaluated the effect of different intraradicular retainers and cementation agents on the fracture resistance of devitalized teeth. Incisive teeth ( n = 40) of bovine mandibles were used. After preparation of the root canals, they were immersed in polyether, in a polyvinyl chloride cylinder containing acrylic resin, to simulate the periodontal ligament. The specimens were randomly divided into four groups ( n = 10), according to the type of retainer (anatomical or main with accessory posts) and resin cement used (conventional resin cement - RelyX ARC or self-adhesive resin cement - RelyX U200). The specimens were stored in distilled water at 37°C and submitted to fracture resistance testing. ANOVA and Tukey's test were applied for data analysis, with significance level set at 5%., Results: There was no interaction between cement type and intraradicular retainers ( P = 0.56) or even between the types of cement used ( P = 0.65). However, in the variation of the types of retainers, the group using main with accessory posts presented greater resistance to the fracture than the anatomical post ( P = 0.04)., Conclusion: Different cementing agents have no effect on the fracture strength of devitalized teeth, unlike the use of posts, in which the use of accessory post proved more resistant when compared to the anatomical post., Competing Interests: The authors of this manuscript declare that they have no conflicts of interest, real or perceived, financial or non-financial in this article., (Copyright: © 2020 Dental Research Journal.)
- Published
- 2020
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