Efeito da incorporação de nanocristais de celulose em uma resina acrílica para base protética sobre propriedades superficiais e formação de biofilmes simples e misto de Candida albicans e Staphylococcus aureus sensível a meticilina (MSSA)
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Data
2021-05-27
Autores
Santana, Thaís de Sousa
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A utilização de biopolímeros de fontes renováveis como agentes de reforço nanométricos pode representar uma importante inovação em materiais odontológicos. O objetivo desse estudo foi avaliar a adesão e formação de biofilmes simples e mistos de Candida albicans e Staphylococcus aureus sensível à meticilina (MSSA) e a viabilidade dos micro-organismos na superfície de uma resina acrílica para base de prótese, após a incorporação de nanocristais de celulose (NC). Nanocristais de celulose (NC) isolados a partir de polpa de madeira (Eucalyptus Urograndis) foram incorporados em uma resina acrílica para base de prótese (Onda-Cryl® - OC, ativada por energia de micro-ondas). Discos de resina acrílica (15 x 3 mm) foram obtidos (N=240) em cada condição experimental (grupos 0%NC - controle e 0,75%NC). Previamente aos testes de adesão e formação de biofilmes, foi mensurada a rugosidade média da superfície dos discos (n=120) em rugosímetro digital (Ra, µm) e a energia livre de superfície (ELS) a partir de medidas de ângulo de contato (n=120), obtidas por meio de um goniômetro conectado a um sistema computadorizado. Foi realizada a formação de biofilmes a partir dos inóculos de C. albicans e S. aureus sobre os discos de resina, os quais foram incubados a 37ºC por 90 minutos e 48h. Após ambos os períodos, foram feitas as análises de: metabolismo celular pelo ensaio do XTT (n=9); avaliação da atividade antimicrobiana através da contagem de unidades formadoras de colônias (UFC/ml) (n=9) e análise por microscopia confocal a laser (n=2). Todas as análises foram realizadas em triplicata em 3 ocasiões distintas. Os dados foram tabulados e submetidos aos testes T de Student e teste não paramétrico U de Mann-Withney, de acordo com a aderência à normalidade, e foi empregado um nível de significância de 5%. A incorporação de NC (0,75%) não exerceu influência sobre os resultados de rugosidade e ELS para a resina OC (P>0,05). Também foi observado, (método XTT e log UFC/mL), que não houve diferença significante entre os grupos para a adesão e formação de biofilme dos diferentes micro-organismos analisados. A microscopia confocal mostrou marcações que evidenciam a viabilidade dos micro-organismos e estas foram semelhantes para ambos os grupos (Controle e NC 0,75%). Dessa forma, conclui-se que a incorporação de 0,75% de NC não exerceu influência sobre as propriedades físicas (rugosidade e energia livre de superfície) e microbiológicas (adesão e formação de biofilme/microscopia confocal) da resina acrílica para base protética.
The use of biopolymers from renewable sources as nanometric reinforcing agents can represent an important innovation in dental materials. The aim of this study was evaluate the simple and mixed biofilm formation of Candida albicans and methicillin-susceptible Staphylococcus aureus (MSSA) and microorganisms’ viability on the surface of acrylic resin for denture base, after the incorporation of cellulose nanocrystals (CN). Cellulose nanocrystals (NC) isolated from wood pulp (Eucalyptus Urograndis) were incorporated into acrylic resin for denture base (Onda-Cryl® - OC, activated by microwave energy). Disc-shaped specimens (15 x 3 mm) were obtained (N=240) for each condition (groups 0%CN - control, and 0.75%CN) Prior to the adhesion and biofilm formation tests, the surface roughness was measured (n=120) in a digital rugosimeter (Ra, µm) and the surface free energy (SFE) was measured from contact angle measurements (n=120), obtained by means of a goniometer connected to a computerized system. The formation of biofilms was performed from the inoculation of C. albicans and S. aureus on the acrylic resin discs, which were incubated at 37ºC for 90 minutes and 48h. After both periods, the analysis of cell metabolism test (XTT) was performed (n=9); evaluation of antimicrobial activity by counting colony-forming units (CFU/ml) (n=9) and analysis by confocal laser microscopy (n=2). All analyses were performed in triplicate on 3 distinct occasions. Data were tabulated and submitted to Student t test and non-parametric Mann-Withney U test, according to adherence to normality, at 5% of significance level. The incorporation of NCs (0.75%) did not influence the results of the surface roughness and surface free energy (SFE) tests for OC acrylic resin (P>0.05). It was also observed, (XTT method and CFU/mL log), that there was no significant difference between the groups for the adhesion and formation of biofilm of the different microorganisms analyzed. The confocal laser microscopy exhibited images that show the viability of the microorganisms and these were similar for both groups (control and NC 0.75%). Thus, it could be concluded that the incorporation of 0.75% of NC did not influence the physical (roughness and free surface energy) and microbiological (adhesion and biofilm formation/confocal microscopy) properties of the acrylic resin for denture base.
The use of biopolymers from renewable sources as nanometric reinforcing agents can represent an important innovation in dental materials. The aim of this study was evaluate the simple and mixed biofilm formation of Candida albicans and methicillin-susceptible Staphylococcus aureus (MSSA) and microorganisms’ viability on the surface of acrylic resin for denture base, after the incorporation of cellulose nanocrystals (CN). Cellulose nanocrystals (NC) isolated from wood pulp (Eucalyptus Urograndis) were incorporated into acrylic resin for denture base (Onda-Cryl® - OC, activated by microwave energy). Disc-shaped specimens (15 x 3 mm) were obtained (N=240) for each condition (groups 0%CN - control, and 0.75%CN) Prior to the adhesion and biofilm formation tests, the surface roughness was measured (n=120) in a digital rugosimeter (Ra, µm) and the surface free energy (SFE) was measured from contact angle measurements (n=120), obtained by means of a goniometer connected to a computerized system. The formation of biofilms was performed from the inoculation of C. albicans and S. aureus on the acrylic resin discs, which were incubated at 37ºC for 90 minutes and 48h. After both periods, the analysis of cell metabolism test (XTT) was performed (n=9); evaluation of antimicrobial activity by counting colony-forming units (CFU/ml) (n=9) and analysis by confocal laser microscopy (n=2). All analyses were performed in triplicate on 3 distinct occasions. Data were tabulated and submitted to Student t test and non-parametric Mann-Withney U test, according to adherence to normality, at 5% of significance level. The incorporation of NCs (0.75%) did not influence the results of the surface roughness and surface free energy (SFE) tests for OC acrylic resin (P>0.05). It was also observed, (XTT method and CFU/mL log), that there was no significant difference between the groups for the adhesion and formation of biofilm of the different microorganisms analyzed. The confocal laser microscopy exhibited images that show the viability of the microorganisms and these were similar for both groups (control and NC 0.75%). Thus, it could be concluded that the incorporation of 0.75% of NC did not influence the physical (roughness and free surface energy) and microbiological (adhesion and biofilm formation/confocal microscopy) properties of the acrylic resin for denture base.
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Palavras-chave
Resina acrílica, Nanopartículas, Biofilme, Acrylic resin, Nanoparticles, Biofilm