Evaluación de la deformación de dos siliconas para prótesis faciales, influencia de la pigmentación y desinfección química

The purpose of present study was to analyze the effect of pigmentation and chemical disinfection on the initial and the permanent deformation of two silicones (Silved Selant and Brascoved) for facial prosthesis. Initial and permanent deformation tests samples (20 mm × 12.5 mm) were made following the manufacturer's instructions. For each silicone (n= 40), ten samples were used for pigmentation with make up power, ten with iron oxide, ten with ceramics power and tem were tested without pigmentation. Five samples of each group were submitted to chemical disinfection using a 2 % Chlorhexidine spray. All samples were immersed in physiological saline and stored in an oven at 35 ° ± 1 °C. After 90 days, the samples were submitted to initial and permanent deformation tests using a dial indicator. For both properties, data were analyzed by Tukey's test (a= 0.05). The results showed that all the materials had initial and permanent deformation regardless of pigmentation and chemical disinfection. The groups were used for pigmentation with iron oxide showed less initial and permanent deformation when were submitted to the chemical disinfection regardless the silicone used.

Effect of disinfection and accelerated ageing on dimensional stability and detail reproduction of a facial silicone with nanoparticles

The aim of the present study was to evaluate the effect of disinfection and accelerated ageing on the dimensional stability and detail reproduction of a facial silicone with different types of nanoparticle. A total of 60 specimens were fabricated with Silastic MDX 4-4210 silicone and they were divided into three groups: colourless and pigmented with nanoparticles (make-up powder and ceramic powder). Half of the specimens of each group were disinfected with Efferdent tablets and half with neutral soap for 60 days. Afterwards, all specimens were subjected to accelerated ageing. Both dimensional stability and detail reproduction tests were performed after specimen fabrication (initial period), after chemical disinfection, and after accelerated ageing periods (252, 504 and 1008 hours). The dimensional stability test was conducted using AutoCAD software, while detail reproduction was analysed using a stereoscope magnifying glass. Dimensional stability values were statistically evaluated by analysis of variance (ANOVA) followed by Tukey's test (p < 0.01). Detail reproduction results were compared using a score. Chemical disinfection and also accelerated ageing affected the dimensional stability of the facial silicone with statistically significant results. The silicone's detail reproduction was not affected by these two factors regardless of nanoparticle type, disinfection and accelerated ageing. © 2012 Informa UK, Ltd.

Influence of natural weathering on colour stability of materials used for facial prosthesis

Colour stability of resin and silicone is an important factor for longevity of facial prostheses. The aim of this study was to evaluate the colour stability of resins and silicone for facial prostheses. Three brands of acrylic resin and one of facial silicone were evaluated considering pigment incorporation for the colourless materials. Ten samples of each material were fabricated and submitted to measurements of chromatic alteration initially and after 90 and 180 days of weathering natural through visual analysis and spectrophotometry. Data were evaluated by ANOVA and Tukey test (p < 0.05). Statistically significant colour alteration was observed among some materials regardless of the period. The materials did not present a statistical difference between 90 and 180 days except for the pigmented heat-polymerized resin. The colour difference between pigmented Silastic MDX4-4210 and colourless Silastic was statistically significant (p < 0.01) in both periods as well as between pigmented and colourless heat-polymerized resin, and between the resins Rapidaflex and Lentaflex. The visual method demonstrated colour alteration in all materials evaluated during the first 90 days of ageing. All materials exhibited colour alteration due to exposure to environment. © 2012 Informa UK, Ltd.

Study of the influence of the rare earth elements (Ce3+ and Ce4+) concentration on the siloxanes coating applied on the copper surface

This work studied the influence of the rare earth (Ce3+ and Ce4+) elements concentration in polysiloxane flints deposited on copper by dip-coating process, and evaluated their resistance in a 3.5 wt.% NaCl medium. Classical electrochemistry techniques were used as open circuit potential, polarization curves and electrochemical impedance spectroscopy. The results revealed that by adding low concentration of Ce4+ ions, the coating prevents the electrolyte uptake any longer retarding the substrate degradation consequently. ©The Electrochemical Society.

Influence of benzoyl peroxide (BPO) on polysiloxane thin films doped with Ce(III) onto tin coated steel and their anticorrosion properties

The influence of benzoyl peroxide (BPO) on the synthesis of polysiloxane thin films doped with Ce(III) deposited onto Sn coated steel as well as their anticorrosion properties are reported. The addition of BPO, whose role is polymerize the film, showed an increase in |Z| values due to the fact that augments the crossed link bonds and therefore improves the protective feature of the film. Ce(III) does not act in the polymerization process and thus is essential the addition of BPO to obtain more resistant polysiloxane films. ©The Electrochemical Society.

Análise histológica e morfométrica de área cruenta tratada com membrana de silicone: estudo em rato

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação da biocompatibilidade de vários elastômeros de silicone implantados no tecido subcutâneo de ratos: estudo histológico e histomorfométrico

Pós-graduação em Odontologia - FOA

Estudo comparativo entre as esferas de silicone gelatinosas e rígidas em cavidade eviscerada de coelho

Pós-graduação em Bases Gerais da Cirurgia - FMB

Influência do processamento de próteses totais maxilares com diferentes espessuras da base: análise gráfica da movimentação dos dentes artificiais

Pós-graduação em Odontologia - FOA

Avaliação da ação do laser de baixa intensidade sobre a cápsula de implantes mamários de silicone: estudo experimental em ratos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influência do ultra-som externo na arquitetura histológica da cápsula orgânica dos implantes de silicone liso: estudo experimental em ratos

Pós-graduação em Ginecologia, Obstetrícia e Mastologia - FMB

Influência de pigmentos e opacificadores na estabilidade de cor, dureza, absorção e solubilidade de um silicone facial submetido ao envelhecimento acelerado

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

O uso da termociclagem na avaliação da absorção, solubilidade, dureza e alteração de cor de reembasadores resilientes

Pós-graduação em Odontologia - FOA

Influência da adição de nanopartículas sobre a dureza, resistência à ruptura e deformação permanente de silicone facial submetido ao envelhecimento acelerado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação do potencial de sistemas nanoestruturados inovadores para incorporação de cacau orgânico: estudo da estabilidade físico-química e atividade antioxidante

Ultimamente várias áreas da ciência vêm se unindo a fim de compreender, elucidar, retardar e reverter o processo do envelhecimento da pele. Tal processo deve ser estudado, pois as mudanças no aspecto exterior podem revelar disfunções que ocorrem internamente, além de trazer conseqüências psíquicas sobre o comportamento da pessoa, tanto diante de si mesma como diante das outras. A utilização de matérias-primas naturais orgânicas em formulações farmacêuticas e cosméticas segue uma tendência de mercado, haja vista o grande impulso que o mercado orgânico tem ocasionado na economia. Dentre estas matérias-primas, destaca-se a utilização do cacau orgânico que, pelo fato de ser rico em compostos polifenólicos e taninos condensados, acredita-se apresentar potencial ação antioxidante. Associados a sistemas nanoestruturados inovadores, como os sistemas líquido-cristalinos constituídos por silicones formadores de filme, a ação antioxidante do cacau orgânico pode, dessa forma, ser potencializada. Este trabalho tem como objetivos desenvolver e caracterizar sistemas líquido-cristalinos acrescidos de extrato de semente de cacau orgânico, avaliar a estabilidade físico-química e a atividade antioxidante das formulações obtidas. Realizou-se a caracterização do pó de cacau por microscopia óptica. A partir do pó do cacau, obteve-se extratos hidroalcóolicos do pó, a partir do qual foram quantificados compostos fenólicos utilizando o reagente Folin-Ciocalteu e determinada a atividade antioxidante com base na ação seqüestrante do radical 1,1-difenil-2-picrilhidrazila (DPPH). Posteriormente, o extrato foi incorporado em um sistema constituído por acido oléico e polioxietileno 20 cetil éter, o qual foi caracterizado estruturalmente empregando análises de microscopia de luz polarizada, espalhamento de raios-X a baixo ângulo (SAXS) e comportamento reológico... (Resumo completo, clicar acesso eletrônico abaixo)