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

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-...

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...

Fracture resistance of composite resin cores with or without prefabricated posts over different substrates.

The fracture resistance of endodontically treated teeth has been an obstacle to the durability of the remaining teeth and restorations. The aim of this study was to evaluate the fracture resistance of endodontically treated bovine and human teeth that were restored with either prefabricated metal posts, glass fiber posts, or composite resin cores. Statistical analysis revealed significant difference between different substrates, but there was no statistically significant difference between different types of intraradicular posts or in the interaction between substrate and post types. The intraradicular posts do not increase the fracture resistance of endodontically treated teeth. The metal posts presented more unfavorable fracture modes when compared to glass fiber posts and composite resin cores.

Correlação entre a análise de Carrea e as dimensões intra-arcos de Nouer em crianças com dentição decídua clinicamente normal / Correlation between morphological analyses and intra-arch dimensions in child with deciduous dentition clinically normal

O objetivo deste estudo foi avaliar a forma do arco dentário decíduo, verificando a correlação com as dimensões intra-arcos. Foram avaliados modelos de gesso de 30 crianças leucodermas de três a cinco anos, com dentição decídua completa, hígida, oclusão clinicamente normal e ausência de hábitos bucais deletérios, sendo que as crianças foram divididas por gênero. Foram utilizadas a análise de Carrea (1920) e as medidas intra-arcosde Nouer (1982): perímetro, comprimento total do arco e dos segmentos anterior e posteriore distâncias intermolares e intercaninos. Os dados demonstraram que o triângulo equilátero (ABC) descrito por Carrea foi observado em apenas 80% e 53,3% dos modelos superiores e em 40% e 20% dos modelos inferiores, nos meninos e meninas, respectivamente. Nosdemais casos foram encontrados triângulos isósceles. A coincidência entre a medida do perímetro do segundo molar inferior e a distância entre os segundos molares superiores, como Carrea afirmou existir, foi observada em apenas 30% da amostra. As correlaçõesentre as medidas dos triângulos e as dimensões intra-arcos foram analisadas por meio da correlação de Pearson (p < 0,05) e foram significativas entre a base dos triângulos (BC) e as distâncias intermolares (superior r = 0,90 e inferior r = 0,72) e entre BC e as distâncias intercaninos (superior r = 0,75 e inferior r = 0,64). Além disso, também houve correlaçãosignificativa entre os lados dos triângulos (AB e AC) e o perímetro dos arcos (superior r =0,70 e inferior r = 0,80). Concluiu-se que a análise de Carrea deve ser utilizada criteriosamente, associando-a com mensurações intra-arcos, como as de Nouer, para uma correta avaliação da dentição decídua.

The aim of this study was to evaluate the deciduous dental arch form, verifyingthe correlation with the intra-arch dimensions. It was evaluated dental casts of the 30 Caucasian children, aged between 3 and 5 years with complete deciduous dentition, without caries,normal occlusion and absence of deleterious oral habit, they were divided by gender. It was used the Garrea (1920) analyses and the intra-arch measurements by Nouer (1982): perimeter, arch total, anterior and posterior length, and the inter-molar and inter-canine distances. The data showed that the equilateral triangle (ABG) was observed in just 80% and 53.3% of theupper casts, and in 40% and 20% of the lower cast, on boys and girls, respectively. In the other cases, it was observed isosceles triangles. The coincidence between the second lowermolar perimeter and the second upper molar distances, according to Garrea affirmative, was observed injust 30% of this data. The correlation between the measurements of the trianglesand the intra-arch dimensions were analyzed by Pearson correlation (p < 0.05) and they were significant between the triangle bases (BG) and the inter-molar distances (upper r = 0.90 andlower r = 0.72), and between BG and the inter-canines distances (upper r = 0.75 and lower r = 0.64). Besides that, it was found significant correlation between the triangles sides (AB and AG) and the arch perimeters (upper r = 0.70 and lower r = 0.80). It was conclude thatthe Garrea analyses must be used with criteria and associated with intra-arch measurements, as Nouer's one, for a correct evaluation of the deciduous dentition.