Avaliação in vitro do efeito-dose resposta da nanoemulsão do extrato etanólico de Lychnophora pinaster sobre células planctônicas e biofilme de Streptococcus mutans e sobre a desmineralização do esmalte dental ao redor de braquetes ortodônticos / In vitro evaluation of dose-response effect of ethanolic extract nanoemulsion of Lychnophora pinaster on Streptococcus mutans planktonic cells and biofilm, as well as on dental enamel demineralization around orthodontic brackets

RESUMO

O objetivo deste trabalho foi avaliar in vitro o efeito dose-resposta da nanoemulsão do extrato etanólico de Lychnophora pinaster sobre células planctônicas e biofilme de Streptococcus mutans UA159 ATCC700610 e sobre a desmineralização do esmalte dental ao redor de braquetes ortodônticos. Além disso, foi avaliada a associação do íon flúor (F-), contido em um dos materiais de colagem de braquetes (Fuji Ortho LC), com a nanoemulsão, assim como a interferência da mesma sobre a força de adesão dos braquetes. Com as células planctônicas foram realizados Testes de Disco Difusão (DD), Concentração Inibitória Mínima (CIM) e Concentração Bactericida Mínima (CBM). A formação do biofilme sobre blocos de esmalte dental bovino, tendo braquetes Synergy colados, foi induzida utilizando-se meio de cultura Müller Hinton cátion ajustado (CLSI M7-A6), com exposição 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 (nanoemulsão 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. Após 48 horas, os biofilmes foram tratados 2x/dia, durante 1 minuto, com NaCl 0,9% (controle negativo), nanoemulsão (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. Após 120 horas os biofilmes foram coletados e foi determinado peso seco, micro-organismos viáveis (UFC) e concentração de F-...

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 cátion adjusted Müller 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 μm of distance from the bracket, and it was evaluate the brackets shear strength according to bond materials...