Resumo: O objetivo deste trabalho foi avaliar in vitro o efeito dose-resposta da nanoemulsão do extrato etanolico de Lychnophora pinaster sobre celulas planctonicas e biofilme de Streptococcus mutans UA159 ATCC700610 e sobre a desmineralizacao do esmalte dental ao redor de braquetes ortodonticos. Alem disso, foi avaliada a associacao do ion fluor (F-), contido em um dos materiais de colagem de braquetes (Fuji Ortho LC), com a nanoemulsao, assim como a interferencia da mesma sobre a forca de adesao dos braquetes. Com as celulas planctonicas foram realizados Testes de Disco Difusao (DD), Concentracao Inibitoria Minima (CIM) e Concentracao Bactericida Minima (CBM). A formacao do biofilme sobre blocos de esmalte dental bovino, tendo braquetes Synergy colados, foi induzida utilizando-se meio de cultura Muller Hinton cation ajustado (CLSI M7-A6), com exposicao 8x/dia, durante 1 minuto, a sacarose 10%. Os blocos foram divididos em experimentos de acordo com o material de colagem, Transbond XT ou Fuji Ortho LC. Para cada material foram avaliados 6 grupos (n=4); 2 controles negativos (48 e 120 horas), 3 experimentais (nanoemulsao na CIM; CIM x 100; CIM x 1000) e 1 controle positivo (digluconato de clorexidina - CHX 0,12%), sendo que os experimentos foram realizados em duplicata. Apos 48 horas, os biofilmes foram tratados 2x/dia, durante 1 minuto, com NaCl 0,9% (controle negativo), nanoemulsao (experimentais), ou CHX 0,12% (controle positivo). Os meios foram trocados a cada 12 horas e o pH mensurado a cada troca para avaliar a acidogenicidade do biofilme. Apos 120 horas os biofilmes foram coletados e foi determinado peso seco, micro-organismos viaveis (UFC) e concentracao de F-. A desmineralizacao do esmalte dental foi determinada em seccao transversal (DZ), nas posicoes 0, 100 e 500 ¿Êm de distancia do braquete e foi verificada a resistencia ao cisalhamento dos braquetes de acordo com os materiais de colagem. Os resultados demonstraram que o halo inibitorio da nanoemulsao foi similar ao da CHX 0,12% e a CIM/CBM se apresentaram abaixo de 500 ¿Êg/mL, o que indica uma forte inibicao ao Streptococcus mutans UA159 ATCC700610. No biofilme formado utilizando ambos os materiais de colagem, a nanoemulsao CIM x 1000 foi similar a CHX 0,12% na diminuicao da UFC/peso seco. Quanto a desmineralizacao, utilizando Transbond XT, a nanoemulsao CIM x 100 ou 1000 foi similar a CHX 0,12% e utilizando Fuji Ortho LC, a nanoemulsao a partir da CIM foi similar a CHX 0,12%. Para todos os grupos, a distancia 0 ¿Êm apresentou maior desmineralizacao que as distancias 100 e 500. A media de resistencia ao cisalhamento do experimento utilizando Transbond XT foi superior a do experimento utilizando Fuji Ortho LC, porem nao houve diferenca entre os grupos em nenhum dos experimentos. Os resultados sugerem que a nanoemulsao do extrato etanolico de Lychnophora pinaster foi efetiva contra celulas planctonicas e biofilme de Streptococcus mutans UA159 ATCC700610 e sobre a desmineralizacao do esmalte dental ao redor de braquetes ortodonticos, sem interferir na forca de adesao dos braquetes, sendo que combinada ao F- do Fuji Ortho LC, o efeito de inibicao da desmineralizacao foi potencializado Ver menos

Abstract: The aim of this study was to evaluate the in vitro dose-response effect of ethanolic extract nanoemulsion of Lychnophora pinaster on planktonic cells and biofilm of Streptococcus mutans UA159 ATCC700610, as well as on dental enamel demineralization around orthodontic brackets. Moreover, it was evaluate the association of the ion fluorine (F-), contained in one of the bracket bond materials (Fuji Ortho LC), with the nanoemulsion, as well as the interference of the nanoemulsion on the brackets bond strength. With planktonic cells, the following tests were performed: Disk Diffusion Testing (DD), Minimal Inhibitory Concentration (MIC), and Minimal Bactericidal Concentration (MBC). The biofilm was formed on bovine enamel blocks, in which Synergy brackets were bonded, using cation adjusted Muller Hinton broth medium (CLSI M7-A6), exposed to 10% sucrose, during 1, minute 8x/day. The blocks were divided into experiments, according to the brackets bond materials, i.e., Transbond XT or Fuji Ortho LC. Six groups (n=4) were evaluated for each material,i.e., two negative control groups (48 and 120 hours), three experimental groups (nanoemulsion at MIC; MIC x 100; MIC x 1000) and one positive control group (chlorhexidine digluconate - 0.12% CHX), considering that the experiments were performed in duplicate. After 48 hours, biofilms were treated 2xday, during 1 minute, with 0.9% NaCl (negative control group), nanoemulsion (experimental groups) or 0.12% CHX (positive control group). The media was changed every 12 hours and the pH was determined every change to evaluated the biofilm acidogenicity. After 120 hours the biofilms were collected and it was determined dry weight, viable microorganisms (UFC) and F- concentration. The dental enamel demineralization was determined in transverse section (DZ) on positions 0, 100 and 500 ¿Êm of distance from the bracket, and it was evaluate the brackets shear strength according to bond materials. The results showed that the nanoemulsion presents the same inhibitory halo than 0.12% CHX and a MIC/MBC lower than 500 ¿Êg/mL, that indicates a higher inhibition of Streptococcus mutans UA159 ATCC700610. Regarding the biofilm formed with both materials, the nanoemulsion 1000 x MIC was similar to 0.12% CHX in the UFC/dry weight reduction. Concerning the demineralization, using Transbond XT, the nanoemulsion 100 and 1000 x MIC was similar to CHX 0.12%, and using Fuji Ortho LC, the nanoemulsion at MIC was similar to 0.12% CHX. For all groups, the distance 0 ¿Êm presented higher demineralization than the distances 100 and 500. The mean shear bond strength for Transbond XT experiment was higher than Fuji Ortho LC experiment, however did not have difference among groups in none of the experiments. The results suggest that the ethanolic extract nanoemulsion of Lychnophora pinaster was effective against Streptococcus mutans UA159 ATCC700610 planktonic cells and biofilm, as well as on dental enamel demineralization around orthodontic brackets, without interfere on brackets bond strength, and in association with the Fuji Ortho LC F-, the demineralization inhibition effect was enhanced. Ver menos