Efeito de adesivos modificados por nanopartículas de TiO2 decoradas ou não com prata em diferentes propriedades
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Data
2017-09-21
Autores
Souza, Victor Trassi Fernandes Silva de [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O presente estudo teve como objetivo a avaliação do efeito antibacteriano de sistemas adesivos modificados com nanopartículas (NPs) de dióxido de titânio (TiO2) decoradas ou não por prata (Ag) em diferentes concentrações, assim como o grau de conversão e a resistência de união à dentina sendo avaliada imediatamente e após três meses em saliva artificial. Os sistemas adesivos AdperTM Scotch Bond Multi Purpose e AdperTM Single Bond (3M Espe), e Clearfil SE Bond (Kuraray) foram modificados com concentrações 0 (controle); 1; 2 e 5% de NPs de TiO2 (com e sem Ag). Foram confeccionados espécimes cilíndricos em resina composta (FiltekTM Z250XT, 3M Espe) na cor A2 com matrizes metálicas (4x2mm), nos quais foram aplicados os sistemas adesivos modificados ou não, de acordo com as instruções dos fabricantes, para o teste de atividade antibacteriana por contato direto. Os espécimes foram colocados em placa de 24 poços e incubados por 18 horas a 37ºC em atmosfera de microaerofilia juntamente com 100μL de suspensão bacteriana padronizada contendo Streptococcus mutans e 900μL de BHI caldo + sacarose (1%). Para a contagem de unidades formadoras de colônias (UFC/mL), foram realizadas diluições seriadas com as soluções resultantes e 50μL dessas diluições foram plaqueadas em placas de petri contendo BHI ágar, sendo incubadas a 37ºC em 10% de CO2 por 48 horas. O grau de conversão foi avaliado por espectroscopia infravermelho por transformada de Fourier (FT-IR) para todos os adesivos modificados ou não em todas as concentrações, sob resolução de 4cm-1, 64 escaneamentos de 400-4000cm-1. Para o teste de microcisalhamento, os espécimes foram confeccionados incluindo fragmentos de dentes bovinos (13mm comprimento x 7mm largura x 2mm espessura) em tubos de PVC (1,2cm x 1,2cm) com resina acrílico autopolimerizável. Nestes espécimes, corpos-de-prova foram confeccionados utilizando-se a resina composta FiltekTM Z250XT (3M Espe) utilizando-se matrizes de teflon em substrato bovino, sobre os quais os sistemas adesivos foram aplicados, sendo feitas as análises de resistência adesiva imediata e após armazenamento em água destilada a 37ºC (±1ºC) por 3 meses. O padrão de fratura dos espécimes foi analisado por microscopia óptica (lupa estereoscópica, 40x de aumento). Os pressupostos de normalidade e homocedasticidade foram atendidos e os dados obtidos foram analisados por Análise de Variância ANOVA (3 fatores) e teste de Tukey (5%). As médias e desvio padrão do grau de conversão foram 25,58 ± 2,25 (SB), 32,48 ±7,3 (SBM) e 9,63 ± 7,19(CB); TiO2 (1%): 29,57±1,4 (SB) 32,72±8,48 (SBM) 31,66±4,78 (CB); TiO2 (2%): 30,14±8,23 (SB) 35,08±7,57 (SBM) 27,19±8,74 (CB); TiO2 (5%): 27,19±12,11 (SB) 35,77±7,91 (SBM) 39,63±6,95 (CB); AgTiO2-1% 27,35±10,36 (SB) 38,03±7,30 (SBM) 37,47± 7,37(CB); AgTiO2-2% 27,72±10,05 (SB) 33,57±10,19 (SBM) 34,13±8,06 (CB); AgTiO2-5% 28,21±9,03 (SB) 38,7±8,15 (SBM) 31,33±8,5 (CB) (p<0,05). As médias log10 e desvio padrão para o teste antibacteriano por contato direto foram: 6.5 ± 0,30 (SB), 6.63 ± 0,19(SBM) e 6.62 ± 0,14 (CB); TiO2 (1%): 5,50 ± 0,40(SB) 5,62 ± 0,29 (SBM) 5,61 ± 0,19(CB); TiO2 (2%): 5,44 ± 0,36(SB) 5,30 ± 0,50(SBM) 5,55 ± 0,08 (CB); TiO2 (5%): 5,46 ± 0,49(SB) 5,47 ± 0,39(SBM) 5,57 ± 0,1 (CB); AgTiO2-1% 5,84 ± 0,16 (SB) 5,56 ± 0,22 (SBM) 5,54 ± 0,07(CB); AgTiO2-2% 5,68 ± 0,45 (SB) 5,41 ± 0,10 (SBM) 5,56 ± 0,12(CB); AgTiO2-5% 5,47 ± 0,14 (SB) 5,50 ± 0,14(SBM) 5,52 ± 0,11(CB) (p<0,05). As médias dos valores resistência adesiva em MPa e desvio padrão para o teste de microcisalhamento (imediato) foram: 19,3 ± 2,7 (SB), 22,4 ± 3 (SBM) e 16,6 ± 2,9 (CB); TiO2 (1%): 18,7 ± 2,4 (SB) 22,8 ± 4,8 (SBM) 15,2 ± 2,7 (CB); TiO2 (2%): 17,9 ± 2,7 (SB) 21,5 ± 2,8 (SBM) 17,9 ± 3,4 (CB); TiO2 (5%): 18,2 ± 3,01(SB) 21,9 ± 3,9(SBM) 17,5 ± 3,99 (CB); AgTiO2-1% 19,5 ± 3,2 (SB) 23,5 ± 3,8 (SBM) 16,5 ± 3,1 (CB); AgTiO2-2% 18,1 ± 3,1 (SB) 24,2 ± 3,9 (SBM) 14,8 ± 3,2 (CB); AgTiO2-5% 17,2 ±4,5 (SB) 23,3 ± 4 (SBM) 14,1 ± 5 (CB) (p<0,05). As médias dos valores resistência adesiva em MPa e desvio padrão para o teste de microcisalhamento (3 meses) foram: 18,3 ± 1,83 (SB), 18,58 ± 2,31 (SBM) e 18,58 ± 2,23 (CB); TiO2 (1%): 17,92 ± 1,98 (SB) 18,25 ± 2,05 (SBM) 17,5 ± 1,8 (CB); TiO2 (2%): 17,83 ± 1,85 (SB) 18,17 ± 2,,04 (SBM) 17 ± 2,59 (CB); TiO2 (5%): 17,75 ± 1,96 (SB) 18,17 ± 2,17 (SBM) 18,75 ± 2,01 (CB); AgTiO2-1% 17,75 ± 1,87 (SB) 17,33 ± 1,88 (SBM) 17,42 ± 1,44 (CB); AgTiO2-2% 17,50 ± 2,28 (SB) 17,25 ± 1,96 (SBM) 17,33 ± 2,31 (CB); AgTiO2-5% 18,25 ± 1,91 (SB) 18,3 ± 2,54 (SBM) 19,17 ± 2,21 (CB) (p<0,05). Os resultados mostraram que todos os sistemas adesivos exibiram atividade antibacteriana independente do tipo de nanopartículas utilizada (p<0,05). Porém, nenhuma diferença foi constatada quando comparadas as diferentes concentrações e os diferentes tipos de adesivo (p<0,05). A adição de nanopartículas não afetou o grau de conversão dos sistemas adesivos, não sendo também constatada diferença nos valores de resistência de união, considerando todas as variáveis e os dois períodos de tempo utilizados. Pode-se concluir que a adição de nanopartículas com propriedades antibacterianas promoveram atividade antibacteriana, sobre Streptococcus mutans, aos adesivos odontológicos, sem prejudicar o grau de polimerização e a adesão, podendo ser uma técnica viável para tornar adesivos odontológicos bioativos e diminuir a infiltração de bactérias em restaurações adesivas.
The present study evaluated the antibacterial effect, the degree of conversion and the micro-shear bond strength (immediate and after three months of water storage) of modified dental adhesive systems with TiO2 or Ag/TiO2 nanoparticles at different concentrations. The adhesive systems AdperTM Single Bond (SB), AdperTMScotchTM Bond Multi Purpose (3M Espe) (SBM) and Clearfil SE Bond (Kuraray) (CB) were modified with 1.0, 2.0 and 5.0 wt% of NPs. For the direct-contact test, sterilized specimens (n=36) were made using a metallic matrix (4x2mm) with the composite resin FiltekTMZ250 XT (3M Espe), on which the dental adhesive systems were applied according to the manufacturer’s instructions. Both materials were photo-activated using a LED light-curing unit (LED Radii Plus, SDI). The specimens were placed in a 24-well plate with 100μL of Streptoccocus mutans standardized suspension on their surfaces, 900μL of BHI broth and incubated for 18 hours at 37ºC under an atmosphere containing 5% CO2. A six-fold serial dilution was performed with the resultant solutions. Fifty microliters (50μL) from each dilution was retrieved and spread on brain-heart infusion agar plates and incubated at 37°C under an atmosphere containing 5% of CO2 for 48h and the colony forming units (CFU’s) were registered. For the evaluation of the DC, the specimens were made by the modification of the dental adhesive systems with all concentrations of nanoparticles and stored for 24hs at 37ºC in an incubator. The FTIR analysis was conducted using an attenuated total reflectance unit (ATR) at a 4cm-1 resolution and 64 scans. For the micro-shear bond strength test, One hundred and twenty six standardized dentin specimens were made from bovine incisors and divided into twenty-one groups. The control and modified adhesive systems were applied on the surfaces of the specimens according to the manufacturer’s instructions and composite resin cylinders (FiltekTM Z250XT) were inserted into the bonded surfaces using a Teflon matrix. The test was performed using a universal testing machine, at a cross-head speed of 0,5mm/min until the specimen rupture. The failure modes of the specimens was determined using a stereomicroscope at 40x and was divided into adhesive, cohesive and mixed. The data was assessed by three-way ANOVA and Tukey’s Test (p≤0.05). The mean values and standard deviation for the control groups of the DC test were: 25,58 ± 2,25 (SB), 32,48 ±7,3 (SBM) e 9,63 ± 7,19(CB); TiO2 (1%): 29,57±1,4 (SB) 32,72±8,48 (SBM) 31,66±4,78 (CB); TiO2 (2%): 30,14±8,23 (SB) 35,08±7,57 (SBM) 27,19±8,74 (CB); TiO2 (5%): 27,19±12,11 (SB) 35,77±7,91 (SBM) 39,63±6,95 (CB); AgTiO2-1% 27,35±10,36 (SB) 38,03±7,30 (SBM) 37,47± 7,37(CB); AgTiO2-2% 27,72±10,05 (SB) 33,57±10,19 (SBM) 34,13±8,06 (CB); AgTiO2-5% 28,21±9,03 (SB) 38,7±8,15 (SBM) 31,33±8,5 (CB) (p<0,05). The mean log10 values and standard deviation for the antibacterial test were: 6.5 ± 0,30 (SB), 6.63 ± 0,19(SBM) e 6.62 ± 0,14 (CB); TiO2 (1%): 5,50 ± 0,40(SB) 5,62 ± 0,29 (SBM) 5,61 ± 0,19(CB); TiO2 (2%): 5,44 ± 0,36(SB) 5,30 ± 0,50(SBM) 5,55 ± 0,08 (CB); TiO2 (5%): 5,46 ± 0,49(SB) 5,47 ± 0,39(SBM) 5,57 ± 0,1 (CB); AgTiO2-1% 5,84 ± 0,16 (SB) 5,56 ± 0,22 (SBM) 5,54 ± 0,07(CB); AgTiO2-2% 5,68 ± 0,45 (SB) 5,41 ± 0,10 (SBM) 5,56 ± 0,12(CB); AgTiO2-5% 5,47 ± 0,14 (SB) 5,50 ± 0,14(SBM) 5,52 ± 0,11(CB) (p<0,05). The mean bond strength values (MPa) and standard deviation for the microshear test (immediate) were: 19,3 ± 2,7 (SB), 22,4 ± 3 (SBM) e 16,6 ± 2,9 (CB); TiO2 (1%): 18,7 ± 2,4 (SB) 22,8 ± 4,8 (SBM) 15,2 ± 2,7 (CB); TiO2 (2%): 17,9 ± 2,7 (SB) 21,5 ± 2,8 (SBM) 17,9 ± 3,4 (CB); TiO2 (5%): 18,2 ± 3,01(SB) 21,9 ± 3,9(SBM) 17,5 ± 3,99 (CB); AgTiO2-1% 19,5 ± 3,2 (SB) 23,5 ± 3,8 (SBM) 16,5 ± 3,1 (CB); AgTiO2-2% 18,1 ± 3,1 (SB) 24,2 ± 3,9 (SBM) 14,8 ± 3,2 (CB); AgTiO2-5% 17,2 ±4,5 (SB) 23,3 ± 4 (SBM) 14,1 ± 5 (CB) (p<0,05). The mean bond strength values (MPa) and standard deviation for the microshear test (3 months) were: 18,3 ± 1,83 (SB), 18,58 ± 2,31 (SBM) e 18,58 ± 2,23 (CB); TiO2 (1%): 17,92 ± 1,98 (SB) 18,25 ± 2,05 (SBM) 17,5 ± 1,8 (CB); TiO2 (2%): 17,83 ± 1,85 (SB) 18,17 ± 2,,04 (SBM) 17 ± 2,59 (CB); TiO2 (5%): 17,75 ± 1,96 (SB) 18,17 ± 2,17 (SBM) 18,75 ± 2,01 (CB); AgTiO2-1% 17,75 ± 1,87 (SB) 17,33 ± 1,88 (SBM) 17,42 ± 1,44 (CB); AgTiO2-2% 17,50 ± 2,28 (SB) 17,25 ± 1,96 (SBM) 17,33 ± 2,31 (CB); AgTiO2-5% 18,25 ± 1,91 (SB) 18,3 ± 2,54 (SBM) 19,17 ± 2,21 (CB) (p<0,05).The results showed that all adhesive systems exhibited effective antibacterial activity, regardless of the NPs used (TiO2 or TiO2/Ag). However, no statistical difference was observed between the different concentrations and also when the three types of adhesive systems were compared. The addition of NPs did not exert any influence on the DC and on the bond strength values. No significant difference was found between the control and experimental groups, considering both types of nanoparticles, all concentrations used and both periods of time. It can be concluded that the addition of antibacterial nanoparticles to dental adhesive systems can provide antibacterial activity to these adhesive systems, without compromising their mechanical and adhesion properties, which may reveal a viable technique to reduce the amount of bacteria in adhesive restorations.
The present study evaluated the antibacterial effect, the degree of conversion and the micro-shear bond strength (immediate and after three months of water storage) of modified dental adhesive systems with TiO2 or Ag/TiO2 nanoparticles at different concentrations. The adhesive systems AdperTM Single Bond (SB), AdperTMScotchTM Bond Multi Purpose (3M Espe) (SBM) and Clearfil SE Bond (Kuraray) (CB) were modified with 1.0, 2.0 and 5.0 wt% of NPs. For the direct-contact test, sterilized specimens (n=36) were made using a metallic matrix (4x2mm) with the composite resin FiltekTMZ250 XT (3M Espe), on which the dental adhesive systems were applied according to the manufacturer’s instructions. Both materials were photo-activated using a LED light-curing unit (LED Radii Plus, SDI). The specimens were placed in a 24-well plate with 100μL of Streptoccocus mutans standardized suspension on their surfaces, 900μL of BHI broth and incubated for 18 hours at 37ºC under an atmosphere containing 5% CO2. A six-fold serial dilution was performed with the resultant solutions. Fifty microliters (50μL) from each dilution was retrieved and spread on brain-heart infusion agar plates and incubated at 37°C under an atmosphere containing 5% of CO2 for 48h and the colony forming units (CFU’s) were registered. For the evaluation of the DC, the specimens were made by the modification of the dental adhesive systems with all concentrations of nanoparticles and stored for 24hs at 37ºC in an incubator. The FTIR analysis was conducted using an attenuated total reflectance unit (ATR) at a 4cm-1 resolution and 64 scans. For the micro-shear bond strength test, One hundred and twenty six standardized dentin specimens were made from bovine incisors and divided into twenty-one groups. The control and modified adhesive systems were applied on the surfaces of the specimens according to the manufacturer’s instructions and composite resin cylinders (FiltekTM Z250XT) were inserted into the bonded surfaces using a Teflon matrix. The test was performed using a universal testing machine, at a cross-head speed of 0,5mm/min until the specimen rupture. The failure modes of the specimens was determined using a stereomicroscope at 40x and was divided into adhesive, cohesive and mixed. The data was assessed by three-way ANOVA and Tukey’s Test (p≤0.05). The mean values and standard deviation for the control groups of the DC test were: 25,58 ± 2,25 (SB), 32,48 ±7,3 (SBM) e 9,63 ± 7,19(CB); TiO2 (1%): 29,57±1,4 (SB) 32,72±8,48 (SBM) 31,66±4,78 (CB); TiO2 (2%): 30,14±8,23 (SB) 35,08±7,57 (SBM) 27,19±8,74 (CB); TiO2 (5%): 27,19±12,11 (SB) 35,77±7,91 (SBM) 39,63±6,95 (CB); AgTiO2-1% 27,35±10,36 (SB) 38,03±7,30 (SBM) 37,47± 7,37(CB); AgTiO2-2% 27,72±10,05 (SB) 33,57±10,19 (SBM) 34,13±8,06 (CB); AgTiO2-5% 28,21±9,03 (SB) 38,7±8,15 (SBM) 31,33±8,5 (CB) (p<0,05). The mean log10 values and standard deviation for the antibacterial test were: 6.5 ± 0,30 (SB), 6.63 ± 0,19(SBM) e 6.62 ± 0,14 (CB); TiO2 (1%): 5,50 ± 0,40(SB) 5,62 ± 0,29 (SBM) 5,61 ± 0,19(CB); TiO2 (2%): 5,44 ± 0,36(SB) 5,30 ± 0,50(SBM) 5,55 ± 0,08 (CB); TiO2 (5%): 5,46 ± 0,49(SB) 5,47 ± 0,39(SBM) 5,57 ± 0,1 (CB); AgTiO2-1% 5,84 ± 0,16 (SB) 5,56 ± 0,22 (SBM) 5,54 ± 0,07(CB); AgTiO2-2% 5,68 ± 0,45 (SB) 5,41 ± 0,10 (SBM) 5,56 ± 0,12(CB); AgTiO2-5% 5,47 ± 0,14 (SB) 5,50 ± 0,14(SBM) 5,52 ± 0,11(CB) (p<0,05). The mean bond strength values (MPa) and standard deviation for the microshear test (immediate) were: 19,3 ± 2,7 (SB), 22,4 ± 3 (SBM) e 16,6 ± 2,9 (CB); TiO2 (1%): 18,7 ± 2,4 (SB) 22,8 ± 4,8 (SBM) 15,2 ± 2,7 (CB); TiO2 (2%): 17,9 ± 2,7 (SB) 21,5 ± 2,8 (SBM) 17,9 ± 3,4 (CB); TiO2 (5%): 18,2 ± 3,01(SB) 21,9 ± 3,9(SBM) 17,5 ± 3,99 (CB); AgTiO2-1% 19,5 ± 3,2 (SB) 23,5 ± 3,8 (SBM) 16,5 ± 3,1 (CB); AgTiO2-2% 18,1 ± 3,1 (SB) 24,2 ± 3,9 (SBM) 14,8 ± 3,2 (CB); AgTiO2-5% 17,2 ±4,5 (SB) 23,3 ± 4 (SBM) 14,1 ± 5 (CB) (p<0,05). The mean bond strength values (MPa) and standard deviation for the microshear test (3 months) were: 18,3 ± 1,83 (SB), 18,58 ± 2,31 (SBM) e 18,58 ± 2,23 (CB); TiO2 (1%): 17,92 ± 1,98 (SB) 18,25 ± 2,05 (SBM) 17,5 ± 1,8 (CB); TiO2 (2%): 17,83 ± 1,85 (SB) 18,17 ± 2,,04 (SBM) 17 ± 2,59 (CB); TiO2 (5%): 17,75 ± 1,96 (SB) 18,17 ± 2,17 (SBM) 18,75 ± 2,01 (CB); AgTiO2-1% 17,75 ± 1,87 (SB) 17,33 ± 1,88 (SBM) 17,42 ± 1,44 (CB); AgTiO2-2% 17,50 ± 2,28 (SB) 17,25 ± 1,96 (SBM) 17,33 ± 2,31 (CB); AgTiO2-5% 18,25 ± 1,91 (SB) 18,3 ± 2,54 (SBM) 19,17 ± 2,21 (CB) (p<0,05).The results showed that all adhesive systems exhibited effective antibacterial activity, regardless of the NPs used (TiO2 or TiO2/Ag). However, no statistical difference was observed between the different concentrations and also when the three types of adhesive systems were compared. The addition of NPs did not exert any influence on the DC and on the bond strength values. No significant difference was found between the control and experimental groups, considering both types of nanoparticles, all concentrations used and both periods of time. It can be concluded that the addition of antibacterial nanoparticles to dental adhesive systems can provide antibacterial activity to these adhesive systems, without compromising their mechanical and adhesion properties, which may reveal a viable technique to reduce the amount of bacteria in adhesive restorations.
Descrição
Palavras-chave
treptoccocus mutans, Prata, Nanopartículas, Titânio, Cura luminosa de adesivos dentários, Silver, Nanoparticles, Titanium, Luminous cure of dental adhesives