O objetivo deste estudo foi avaliar o comportamento da dentina radicular bovina frente a duas condições experimentais: a aplicação de soluções de hipoclorito de sódio nas concentrações de 0,5% e 2,5% sobre a superfície da luz radicular e a aplicação das mesmas substâncias seguida do cimento de fosfato de zinco, comparando a microdureza dentinária em duas distâncias em relação à luz do canal, nos terços radiculares. Foram utilizadas 30 raízes de incisivos superiores bovinos. Cada raiz foi seccionada em três posições: terço cervical (C), médio (M) e apical (A). Estas foram submetidas ao teste de microdureza Knoop ( KHN a 100g/15 seg) em duas distâncias, 100 ?m e 300 ?m em relação à luz radicular (momento I). Em seguida receberam um tipo de tratamento formando seis Grupos experimentais: 1A - hipoclorito de sódio a 0,5% , 1B – hipoclorito de sódio a 2,5%,1C – solução fisiológico, 2A – hipoclorito de sódio a 0,5% + fosfato de zinco, 2B – hipoclorito de sódio a 2,5% + fosfato de zinco e 2C – solução fisiológico + fosfato de zinco. Nos Grupos 1A, 1B e 1C após a aplicação das substâncias, as superfícies foram vedadas e decorrida uma semana um novo teste de microdureza Knoop (momento II) foi realizado. Os corpos-de-prova dos Grupos 2A, 2B e 2C receberam as soluções testadas por 60 segundos e em seguida a aplicação do cimento de fosfato de zinco, quando foram vedadas e após uma semana foram submetidos a novo teste de microdureza (momento II). Os corpos-de-prova do Grupo 2A, 2B e 2C foram observados ao MEV na região da interface cimento/dentina. Os resultados foram submetidos à análise de variância com medidas repetidas, pois cada dente foi avaliado em seis combinações entre posição (C, M e A) e distância (100 ?m e 300 ?m) e não apresentaram diferença estatisticamente significante (?=0,05) entre as combinações de posição, distância. Somente houve diferença significante (p=0,0000) quando os valores de KHN foram comparados em relação às distâncias 100 ?m e 300 ?m, sendo que a 300 ?m os valores foram maiores. Assim, os valores referentes aos 3 terços foram agrupados formando uma única média para cada distância. Pelo Teste-t pareado, as médias foram comparadas nos momentos I e II em cada distância e observou-se diferença estatisticamente significante (?=0,05) entre os grupos 1C e 2A (p=0,012 à 100 ?m, p=0,006 à 300 ?m; p=0,024 à 100 ?m e p=0,047 à 300 ?m, respectivamente). Para comparação do comportamento da dentina antes e depois dos tratamentos após uma semana, todas as médias do momento I foram juntadas num único grupo (grupo momento I). A análise de variância o grupo 1C apresentou diferença estatisticamente significante em relação ao grupo formado pelas médias de microdureza no momento I a 100 ?m e 300 ?m; 1B e 2B a 100 ?m e 1B, 2B e 2C a 300 ?m. Com isso, podemos concluir que a dentina radicular sem qualquer tratamento anti-séptico após uma semana apresenta seus valores de microdureza diminuídos de maneira significante em relação às medidas iniciais (I) e aos demais grupos experimentais. / The aim of this study was to evaluate the behavior of the bovine root-dentin under two experimental conditions: the application over the lumen surface with sodium hypochlorite solutions in concentrations of 0,5% and 2,5%, and the application of the same solutions after zinc phosphate cement was applied. The dentin microhardness was compared at two distances from the lumen, in the radicular thirds. In this study, 30 roots of bovine upper incisor were used. Each root was sectioned in the thirds: cervical (C), medium (M) and apical (A), and submitted to the Knoop microhardness test (KHN at 100g/15s) at two distances: 100 ?m and 300 ?m from lumen (I). After that, the species received one type of treatment determining six experimental groups: 1A – sodium hypochlorite 0,5%, 1B - sodium hypochlorite 2,5%, 2C – physiologic solution, 2A - sodium hypochlorite 0,5% + zinc phosphate, 2B - sodium hypochlorite 2,5% + zinc phosphate e 2C - physiologic solution+ zinc phosphate. In the Groups 1A, 1B and 1C after these solutions were applied, surfaces were sealed and one week later a new measure of microhardness (KHN) was taken (II). The Groups 2A, 2B and 2C received the tested solutions for 60 seconds following application of zinc phosphate cement, them they were sealed and after seven days a new measure was taken (II). The samples of Group 2A, 2B and 2C were observed on MEV micrographs in the cement/dentin interface. Analysis of variance with repeated measures, as each tooth was evaluated in six combinations of positions (C, M, A) and distances (100 ?m and 300 ?m), showed that there were no statistical (?=0,05) differences between combinations of position and distance. There was only significant difference (P=0,000) when KHN values were compared in relation to distances (100 and 300?m), and at 300 ?m higher values was found. The values from the thirds were grouped resulting in sole mean for each distance. Pared test-t was run to compare values I and II, in each distance significant difference was found in Group 1C and 2A (P=0,012 at 100, P=0,006 at 300; P=0,024 at 100 e P=0,047 at 300, respectively). To compare dentin behavior pre and post treatments after a week, all averages of values I were joined in a single group (group moment I). Under the Analysis of variance group 1C showed a significant difference in relation to the group formed by averages of microhardness in value I at 100 ?m and 300 ?m; 1B and 2B at 100 ?m and 1B, 2B and 2C at 300 ?m. Therefore, it can be concluded that root dentin with no anti-septic treatment after one week significantly shows decreased values of microhardness in relation to the initial measures (I) and to the others experimental groups.

O presente estudo in vitro objetivou avaliar a longo prazo o potencial antimicrobiano residual e a citotoxicidade de soluções químicas de limpeza de prótese quando incorporadas à resina acrílica termopolimerizável após sucessivos ciclos de imersão noturna diária. Discos (10mm x 1mm) de resina acrílica termopolimerizável para base de prótese (Lucitone 550) foram submetidos a três ciclos diários de desinfecção (8h/cada) em hipoclorito de sódio a 1% (NaClO), digluconato de clorexidina a 2% (CLX) ou água destilada (controle) durante 91 (T91) ou 183 dias (T183), simulando o período de 9 meses ou 1,5 ano de imersão noturna diária realizada pelo paciente. Inicialmente, foi utilizado o método de concentração inibitória mínima em caldo para determinar o possível efeito residual (incorporação) das soluções à resina acrílica. Metade dos discos imersos em cada agente de limpeza em um dos tempos de imersão (n=5) foi inoculada (1x107cels/mL) com um dos patógenos associados à estomatite protética: Candida albicans (Ca) e Staphylococcus aureus (Sa). Os discos foram incubados a 37oC para análise em espectrofotômetro após 24h, 7 e 14 dias. Os valores de absorbância foram convertidos em porcentagens de inibição microbiana. Confirmada a ação antimicrobiana residual dos agentes de limpeza incorporados à resina acrílica, foi então analisada sua citotoxicidade in vitro sobre fibroblastos gengivais humanos (L929). Os efeitos citotóxicos foram avaliados por meio do ensaio colorimétrico MTT [brometo de 3-(4,5-dimetiltiazol-2-yl)-2,5-difeniltetrazólio] para a determinação da viabilidade celular, após as células serem expostas por 24h às amostras de cada condição experimentais (n=18) previamente imersas em uma das soluções por um dos períodos avaliados (T91 ou T183). A citotoxicidade foi determinada com base na atividade mitocondrial em relação a corpos de prova não submetidos à imersão nas soluções testadas. Os resultados do ensaio do MTT foram analisados estatisticamente por ANOVA-1 fator seguida pelo teste post-hoc de Tukey HSD (a=0,05). Para os períodos T91 e T183, não houve inibição microbiana com a imersão em água (controle) em até 14 dias de incubação. A CLX inibiu progressivamente o crescimento microbiano ao longo dos 14 dias para ambos os períodos de imersão (Ca: 19 a 73,58%; Sa: 0 a 87,08%), sendo observada maior ação antimicrobiana em T183. O NaClO apresentou discreta inibição microbiana apenas no período de 14 dias tanto em T91 (Ca: 0%; Sa: 2,70%) quanto em T183 (Ca: 8,50%; Sa: 15,08%). De acordo com os resultados do teste de MTT, as soluções químicas de limpeza testadas apresentaram uma redução significativa da viabilidade celular quando comparado às células controles propagadas apenas em meio de cultura (p<0,002). A CLX resultou na menor viabilidade celular em ambos os períodos de imersão (p<0,018). As amostras de resina acrílica imersas em água ou NaClO em T91 e T183 apresentaram viabilidade celular estatisticamente similar às amostras não imersas (p>0,05). Pode-se concluir que a CLX incorporada à resina acrílica para base de prótese apresentou um efeito antimicrobiano residual em ambos os períodos de imersão noturna, o que não foi observado com o NaClO. Por outro lado, a CLX residual resultou em efeito intensamente citotóxico aos fibroblastos gengivais humanos quando comparada ao NaClO e à agua destilada, que se apresentaram discretamente citotóxicos. Esses resultados sugerem precaução na seleção de agentes de limpeza para prótese como meio de prevenção e tratamento adjunto da estomatite protética, pois mesmo em concentrações baixas, recomendadas para imersão noturna, podem apresentar algum grau de toxicidade às mucosas de suporte protético. / This in vitro study aimed to evaluate the long-term residual antimicrobial activity and cytotoxicity of chemical denture cleansers incorporated into a heat-polymerized acrylic resin after successive cycles of daily overnight soaking. Discs (10mm x 1mm) were prepared from heat-polymerized acrylic resin (Lucitone 550) and submitted to three daily immersion (8h/each) in 1% sodium hypochlorite (NaClO), chlorhexidine digluconate 2% (CHX) or distilled water (control) for 91 days (T91) or 183 days (T183), simulating the period of 9 months or 1.5 year of nocturnal immersion performed by the patient. Initially, the method of minimum inhibitory concentration in broth was used to determine the possible residual effect (incorporation) of the acrylic resin solution. Half of the disks immersed in each cleaning agent for one of the period immersion (n=5) was inoculated (1x107cells/mL) with pathogens associated with denture stomatitis: Candida albicans (Ca) or Staphylococcys aureus (Sa). The disks were incubated at 37oC for analysis in a spectrophotometer after 24h, 7 and 14 days. The absorbance values were expressed as percentages of microbial inhibition. Confirmed the residual antimicrobial action of cleaning agents incorporated into the acrylic resin, its cytotoxicity was analyzed in vitro on human gingival fibroblasts (L929). Cytotoxic effects were evaluated by the colorimetric assay MTT [3- (4,5- dimethylthiazol-2-yl) -2,5-diphenyl tetrazolium bromide] to determine cellular viability after the cells were exposed for 24h to the samples of each experimental condition (n=18) previously immersed in one of the solutions for the evaluation periods (T91 or T183). Cytotoxicity was determined based on mitochondrial activity compared to the specimens not subjected to immersion in the solutions. The MTT assay results were 1-way ANOVA followed by Tukey\'s HSD post-hoc test (a=0.05). For the periods T91 and T183, no microbial inhibition was observed with immersion in water (control) for up to 14 days of incubation. The CHX progressively inhibited microbial growth over the 14 days for both immersion times (Ca: 19 to 73.58%, Sa: 0 to 87.08%); with greater antimicrobial activity in T183. The NaClO showed a slight microbial inhibition only in the 14-day period in both T91 (Ca: 0%; Sa: 2.70%) and T183 (Ca: 8.50%; Sa: 15.08%). According to the results of the MTT assay, the chemical cleaning solutions tested showed a significant reduction in cell viability when compared to the control cells propagated in normal culture medium (p<0.002). The CHX resulted in the lowest cell viability in both immersion periods (p<0.018). The acrylic samples immersed in water or NaClO in T91 and T183 showed cell viability statistically similar to nonimmersed samples (p>0.05). CHX incorporated into the acrylic resin denture base had a residual antimicrobial effect on both immersion periods, which was not observed with NaClO. On the other hand, the residual CHX were severely cytotoxic to human gingival fibroblasts compared to NaClO and distilled water which were slightly cytotoxic. These results suggest caution in selecting denture cleaning agents as a method of prevention and adjunct treatment of denture stomatitis because even at low concentrations recommended for overnight immersion, they may exhibit some degree of toxicity to the denture bearing mucosa.

Orientador: Regina Maria Puppin-Rontani / Tese (doutorado) - Universidade Estadual de Campina, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-12T09:08:02Z (GMT). No. of bitstreams: 1 Pascon_FernandaMiori_D.pdf: 20418378 bytes, checksum: 123cef34dc5e16d51cd9c6553ae586c5 (MD5) Previous issue date: 2008 / Resumo: A utilização de substâncias químicas auxiliares, durante o tratamento endodôntico, pode alterar a composição química e as propriedades físicas da estrutura dentinária corono-radicular. Além disso, pode interferir no processo de união do material restaurador às estruturas dentinárias da câmara pulpar. Dessa maneira, pesquisas devem ser realizadas possibilitando a indicação de uma substância, que apresente o mínimo efeito nas propriedades mecânicas dentinárias, enquanto exerce o efeito de debridamento desejado. No intuito de facilitar a apresentação desta Tese, a mesma foi dividida em três capítulos, como descrito nas proposições seguintes. Capítulo 1: revisar sistematicamente a literatura a respeito dos efeitos da solução de hipoclorito de sódio nas propriedades mecânicas da dentina do canal radicular quando a mesma é utilizada durante o tratamento endodôntico. Capítulo 2: verificar os efeitos de diferentes substâncias químicas auxiliares (soro fisiológico, hipoclorito de sódio, clorexidina gel, peróxido de uréia - Endo-PTC® e EDTA) na microdureza (realizada por meio do teste de microdureza Vickers) e morfologia (realizada por meio de análise em Microscopia Eletrônica de Varredura) da dentina da câmara pulpar de dentes anteriores decíduos e permanentes. Capítulo 3: avaliar o efeito de substâncias químicas auxiliares (soro fisiológico, hipoclorito de sódio, clorexidina gel, peróxido de uréia - Endo-PTC® e EDTA) na rugosidade superficial da dentina da câmara pulpar de dentes decíduos e permanentes. Baseando-se na revisão de literatura pôde-se concluir que há forte evidência de que o hipoclorito de sódio altera as propriedades mecânicas da dentina radicular, quando o mesmo é utilizado como solução irrigadora durante o tratamento endodôntico. O uso de substâncias químicas auxiliares diminuiu os valores de microdureza dentinária Vickers tanto para dentes decíduos quanto para os permanentes. Observaram-se resultados não conclusivos com o uso do EDTA 17% na dentina da câmara pulpar dos dentes decíduos e permanentes uma vez que a microdureza superficial não pôde ser mensurada. A solução de hipoclorito de sódio 1% e 5,25% produziu os menores valores de microdureza Vickers para dentes decíduos e permanentes, comparados à clorexidina gel 2% e grupo controle (soro fisiológico). Alterações morfológicas foram observadas quando a dentina da câmara pulpar foi irrigada com solução de hipoclorito de sódio 1% ou 5,25% associados ao EDTA 17%, EDTA 17% utilizado isoladamente e clorexidina gel 2% associada ou não ao EDTA 17%. Em relação à rugosidade superficial pôde-se concluir que a irrigação da dentina da câmara pulpar aumentou a rugosidade superficial dos dentes permanentes e decíduos tratados com hipoclorito de sódio 1% e 5,25% associados ao EDTA 17%. / Abstract: Irrigation solutions, endodontic auxiliary chemical substance, and chelating agents used on root canal treatment might yield changes in the chemical composition and physical properties of dentin surface, and affect its interaction with materials used for coronal sealing. Thus, studies are required to select a suitable chemical agent, which has minimal effects on the mechanical properties of the tooth whilst achieving the desired debridement effect. In order to facilitate the accomplishment of this Thesis, it was divided into three chapters, as described on the following descriptions. Chapter 1: to present a systematic review on the effect of sodium hypochlorite on the mechanical properties of root canal dentin, considering its use as an irrigation solution. Chapter 2: to verify the effects of endodontic irrigants, auxiliaries chemicals substances and chelating agent on the microhardness (Vickers Hardness test) and morphology (Scanning Electron Microscopy) of the pulp chamber dentin in primary and permanent teeth. Chapter 3: to evaluate the effect of endodontic irrigants, auxiliaries chemicals substances and chelating agent on the roughness of the pulp chamber dentin of primary and permanent teeth. Based on literature review it could be concluded that there is strong evidence showing that sodium hypochlorite alters the mechanical properties of root canal dentin, when used as an endodontic irrigant. The use of irrigation solutions decreased the Vickers Hardness Number values for both permanent and primary teeth. Inconclusive results were observed when 17% EDTA was used, since it could not be measured. Sodium hypochlorite provides lower Vickers Hardness Number for primary and permanent teeth, compared with 2% chlorhexidine and control group (saline solution). Morphological alterations were observed when pulp chamber irrigation was performed by 1% or 5.25% sodium hypochlorite associated with 17% EDTA, 17% EDTA, and 2% chlorhexidine gel associated or no with 17% EDTA. Regarding surface roughness, it was concluded that pulp chamber irrigation with 1% and 5.25% sodium hypochlorite associated with 17% EDTA increases pulp chamber roughness of primary and permanent teeth. / Doutorado / Odontopediatria / Doutor em Odontologia

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-03-27T12:22:55Z No. of bitstreams: 0 / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-03-27T13:44:47Z (GMT) No. of bitstreams: 0 / Made available in DSpace on 2018-03-27T13:44:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-09 / O hipoclorito de sódio (NaOCl) é a solução irrigadora mais comumente utilizada durante a terapia endodôntica. A atividade antimicrobiana e a capacidade de dissolver a matéria orgânica são características bem conhecidas desta solução. No entanto, pouco se conhece sobre os efeitos do NaOCl nas células-tronco mesenquimais humanas. As células-tronco de dentes decíduos humanos esfoliados (SHED) foram cultivadas e expostas a 0,04% de NaOCl durante 30, 60 e 300 segundos. A proliferação e viabilidade celular foram investigadas pelos ensaios de brometo de 3- (4,5-dimetiltiazol-2-il) -2,5-difeniltetrazólio (MTT) e Trypan blue, respectivamente. O potencial de diferenciação foi investigado através da diferenciação osteogênica. A expressão dos marcadores de células-tronco foi avaliada por reação em cadeia da polimerase via transcriptase reversa (RT-PCR). Todos os ensaios foram realizados no 1º dia após o tratamento. Todos os testes mostraram uma redução no número de células viáveis com aumento do tempo de exposição ao NaOCl. Entretanto, não houve diferença entre os grupos em relação a mineralização. Quanto à RT-PCR, a expressão dos genes testados, β-actina, Nestin e CD105 foi significativamente menor. Os resultados mostraram que o longo período de exposição ao NaOCl tem efeitos prejudiciais na sobrevivência de SHEDs. / Sodium Hypochlorite (NaOCl) is the most common irrigation solution and widely used during root canal procedures. The antimicrobial activity and capacity to dissolve organic matter are well known features of this solution. However, there is little knowledge about the effects of NaOCl on human mesenchymal stem cells. Briefly, stem cells from human exfoliated deciduous teeth (SHED) were cultured and exposed to 0.04% NaOCl for 30, 60 and 300 seconds. We investigated cell proliferation and viability by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and trypan blue dye, respectively. Differentiation potential was investigated through osteogenic differentiation. Stem cells markers expression was evaluated by reverse transcriptase polymerase chain reaction (RT-PCR). All the assays were performed at 1 day following treatment. All tests showed a reduction in the number of viable cells with increased exposure time to NaOCl. Interestingly, there was no difference between the groups in relation to mineralization. As for RT-PCR, the expression of the genes tested, β-actin, Nestin and CD105 was significantly lower. The data showed that long exposure period to NaOCl has detrimental effects on the survival of SHEDs.

No Brasil, diariamente, são descartadas 2,3 toneladas de meios de cultura potencialmente contaminados com microorganismos. A resolução RDC No 306/2004 da Agência Nacional de Vigilância Sanitária preconiza que os resíduos devem ser tratados antes do descarte, visando à redução da carga microbiana. Foram desenvolvidos 2 métodos para avaliar a sensibilidade e a eficiência, assim como a concentração ideal, de um agente químico (biocida) contra microorganismos contaminantes. O método de difusão com Perfurador Circular de Ágar (PCA) e o método com Perfurador Linear de Ágar (PLA) foram testados com 13 cepas de microorganismos. O biocida avaliado foi a combinação de hipoclorito de sódio (NaClO) com ácido acético (CH3COOH). A partir destes resultados, foi desenvolvido um equipamento automatizado para processar a redução da carga microbiana (SADEMC) dos meios de cultura contaminados. A redução da carga microbiana foi avaliada pelo método quantitativo da reação da transcriptase reversa com detecção em tempo real. O método PCA mostrou ser reprodutível e eficiente para medir a inibição do crescimento bacteriano de um biocida. A concentração mínima de biocida capaz de reduzir o crescimento microbiano foi de 250 ppm para a solução aquosa de NaClO a 0,25% e de 200 ppm para a de CH3COOH a 0,2%. No SADEMC, foi possível processar 4,6kg de meios de culturas em 100 litros da concentração mínima eficaz do biocida por 15 minutos, e atingir uma redução da carga microbiana de, aproximadamente, 1,4E10 unidades formadoras de colônias. Podemos concluir que o SADEMC promove uma redução de carga microbiana compatível com os níveis exigidos pela RDC No. 306; fornece biossegurança na sua manipulação e que resulta em plástico reciclável. / In Brazil, daily, 2.3 tons of potentially contaminated cultured medium with microorganisms are discarded. The RDC 306 resolution from the Brazilian National Health Department rules out that residue must be treated prior to discart in order to reduce microbial load. Two methods were developed to evaluate the sensitivity, efficiency and ideal concentration of a chemical agent (biocide) against microorganisms. The Ágar\'s Diffusion Method by Circular Perforator (PCA) and by Linear Perforator (PLA) were tested with 13 microorganism lines and the biocide composed by Sodium Hypochlorite (NaClO) and its combination with Acetic Acid (CH3COOH). The microbial load reduction was evaluated by the real time reverse transcription-polymerase chain reaction. From the in vitro data, an automatic equipment to process the potentially contaminated culture media (SADEMC) was developed. The PCA method was reproductive and efficient to measure the bacterial growth inhibition induced by the biocide. The minimum biocide concentration capable to reduce the microbial growth was a solution of 0.25% NaClO (250 ppm) and 0.2% CH3COOH (200 ppm). In the SADEMC, the direct exposition of 4.6 kg of culture media in 100 liters of biocide for a period of 15 minutes is capable to reduce the microbial load in approximately 1,4E10 of colony-forming unit. We may conclude that the SADEMC is able to promote a microbial load reduction more intense than the one demanded by the RDC 306 resolution. In addition to that, the SADEMC contemplates personnel safety and allows recycling the plastic residues

Made available in DSpace on 2014-08-20T13:42:10Z (GMT). No. of bitstreams: 1 Dissertacao_Franciela_Spier.pdf: 855733 bytes, checksum: b77db27392fb17bb6c91b99ba915397c (MD5) Previous issue date: 2010-03-30 / The starch market has been growing and improving, leading to search for products with unique functional properties that industry requirements. The use of native starches is limited, depending on the processing conditions such as temperature, pH, pressure restricting its application in industrial scale. The production of modified starch is an alternative that has been in development for some time in order to overcome one or more limitations of native starches, increasing its use in industry. The objective of this research was to evaluate the properties of corn starch chemically modified, alone or combined action by the acid, oxidative and alkaline. The corn starch granules were treated with a solution of sodium hydroxide at concentrations of 0.09% and 0.18%, with lactic acid solution, 2% and 4%, and a solution of sodium hypochlorite 1% and 2%. Later were neutralized, washed, dried, ground and stored. The starches were evaluated for amylose content, content of carbonyl and carboxyl, paste properties, diffraction of X-ray, swelling power and solubility and enzymatic susceptibility. The corn starch oxidized with sodium hypochlorite (2%) showed a reduction in levels of amylose and treated with alkali and acid increased. The oxidative treatment increased gradually, the levels of carbonyl and carboxyl with increasing concentration of sodium hypochlorite. Among the treatments studied the oxidative treatment was more interference in the pasting properties of starch increased the maximum viscosity and breakdown and reduce the pasting temperature and final viscosity. The interaction between the alkaline and acid treatments affected the crystallinity of maize starch. The oxidative treatment increased the solubility of corn starch at all temperatures examined, especially in the incubation temperatures are higher than the highest concentration (2%), significantly increased the rate of hydrolysis / O mercado de amidos vem crescendo e se aperfeiçoando, levando à busca de produtos com características específicas que atendam às exigências da indústria. A utilização de amidos nativos é limitado, em função das condições de processamento como temperatura, pH e pressão que restringem sua aplicação em escala industrial. A produção de amidos modificados é uma alternativa que vem sendo desenvolvida há algum tempo com o objetivo de superar uma ou mais limitações dos amidos nativos, aumentando sua utilização na indústria. O objetivo do trabalho foi avaliar as propriedades de amido de milho modificado quimicamente, de forma isolada ou combinada, pela ação alcalina, ácida e oxidativa. Os amidos de milho foram tratados com solução de hidróxido de sódio nas concentrações de 0,09% e 0,18%, com solução de ácido lático, 2% e 4%, e com solução de hipoclorito de sódio 1% e 2%. Posteriormente foram neutralizados, lavados, secos, moídos e armazenados. Os amidos foram avaliados quanto ao teor de amilose, teor de carbonila e carboxila, propriedades de pasta, difração de raio-X, poder de inchamento e solubilidade e suscetibilidade enzimática. Os amidos de milho oxidados com hipoclorito de sódio (2%) apresentaram uma redução nos teores de amilose e os tratados com álcali e ácido um acréscimo. O tratamento oxidativo aumentou os teores de carbonila e carboxila com o aumento da concentração de hipoclorito de sódio. Dentre os tratamentos estudados o oxidativo foi o que interferiu mais nas propriedades de pasta do amido, aumentando a viscosidade máxima e a quebra, além de reduzir a temperatura de pasta e a viscosidade final. A interação entre os tratamentos alcalino e ácido aumentou a cristalinidade relativa do amido de milho. O tratamento oxidativo aumentou a solubilidade do amido de milho em todas as temperaturas analisadas, principalmente nas temperaturas de incubação mais elevadas, sendo que na maior concentração (2%), aumentou significativamente a taxa de hidrólise.

No description available.

Afin de maitriser la qualité d'eau dans les réseaux d'eau chaude sanitaire, des traitements de désinfection thermiques et chimiques sont utilisés. Ces traitements de désinfection peuvent avoir un impact sur la dégradation des canalisations. L'influence de l'addition d'hypochlorite de sodium et de l'augmentation de la température sur la vitesse et le mode de dégradation des canalisations en cuivre, acier galvanisé, PERT/Al/PERT et PVCc a été étudiée. Pour ceci, des essais de vieillissement accéléré ont été réalisés en conditions statiques et dynamiques. Afin de réaliser les essais en conditions dynamiques, un banc d'essais à échelle 1 a été conçu et construit.La chimie des solutions d'hypochlorite de sodium à des températures élevées (>50°C) est complexe, ceci a motivé la réalisation d'une étude complémentaire sur les espèces présentes en fonction du pH et la cinétique de décomposition des solutions d'hypochlorite de sodium. Cette étude a révélé que l'augmentation de la température de 50°C à 70°C à une valeur de pH donnée produit une diminution significative de la concentration en acide hypochloreux. De plus, la décomposition de l'hypochlorite de sodium en chlorates est accélérée par la présence de cuivre et elle peut devenir significative à partir de 50°C.Les essais de vieillissement réalisés sur les canalisations ont révélé que l'addition d'hypochlorite de sodium est pénalisante par rapport à la vitesse de dégradation du cuivre, acier galvanisé et PERT/Al/PERT. Cependant, la dégradation du PVCc ne semble pas se voir affectée par l'addition d'hypochlorite de sodium. L'élévation de la température de 50°C à 70°C paraît accélérer légèrement la dégradation du PERT/Al/PERT et du PVCc. En revanche, avec une chloration de 25 ppm en hypochlorite de sodium, le mode de corrosion du cuivre est uniforme à 70°C tandis qu'il est localisé à 50°C.Les conclusions de ces résultats peuvent être d'utilité pour la conception et la maintenance des réseaux d'eau chaude sanitaire. / Hot water quality control inside buildings is assured by thermal or/and chemical disinfection treatments. These disinfection treatments could have an impact on the material degradation. The influence of the addition of sodium hypochlorite and the increase in temperature on the degradation of copper, galvanized steel, PERT/Al/PERT and cPVC pipes was studied. Accelerated ageing tests were conducted under static and dynamic conditions. To carry out the tests under dynamic conditions a scale 1 pilot was designed and built.The chemistry of sodium hypochlorite solutions at temperatures higher than 50°C is complex. Therefore, the species repartition as a function of pH and the decomposition kinetic of sodium hypochlorite solutions had also been studied. This study revealed that, at a given pH, an increase in temperature from 50°C to 70°C produce a significant decrease in concentration of hypochlorous acid. In addition, the decomposition of sodium hypochlorite in chlorates is accelerated by the presence of copper. The chlorates concentration can become significant at 50°C in presence of copper.The results of the ageing test performed on pipes revealed that the addition of sodium hypochlorite increase the degradation rate of copper, galvanized steel and PERT/Al/PERT. However, the degradation rate of cPVC does not seem to be affected by the addition of sodium hypochlorite. An increase in temperature from 50°C to 70°C slightly accelerated degradation of PERT /Al/PERT and cPVC. Concerning copper, at 70°C corrosion is uniform while at 50°C corrosion is by pitting.The conclusions of this study can be useful for the design and the maintenance of hot water systems.

Indiana University-Purdue University Indianapolis (IUPUI) / Introduction: Nonsurgical root canal therapy procedures aim to reduce the total microbial load within an infected root canal system through chemomechanical debridement of the root canal system via instrumentation in conjunction with an antibacterial irrigating solution. The most commonly used irrigant is sodium hypochlorite, often at concentrations toxic to human cells. Electromagnetic wave irradiation is a novel method of disinfection that has been shown to be bactericidal against planktonic microorganisms in solution, but its efficacy against an established biofilm is unknown. Pilot studies have demonstrated a synergistic killing effect with sodium hypochlorite through a process termed electromagnetic stimulation (EMS). If confirmed, lower concentrations of the current gold standard of 6.0-percent sodium hypochlorite could be used to irrigate infected root canals during endodontic treatment, resulting in less toxicity to human cells. There are also regenerative implications as EMS could be used to disinfect the root canals of immature teeth using 1.5-percent sodium hypochlorite, as recommended by the American Association of Endodontists. Objectives: The purpose of this in-vitro study was to evaluate the anti-biofilm effect of EMS against an established biofilm of Enterococcus faecalis. Materials and Methods: Single rooted teeth were cut to a standardized length (12 mm) and instrumented with a 45.05 Wave One Gold reciprocating file. Specimens were sterilized and inoculated with E. faecalis, which grew for two weeks to form an established biofilm. There were five treatment groups: 1) 6.0-percent sodium hypochlorite; 2) 1.5-percent sodium hypochlorite; 3) 1.5-percent sodium hypochlorite with EMS; 4) 0.9-percent saline with EMS and 5) 0.9-percent saline. Samples were collected, plated, and incubated for two days. The number of CFUs/mL was determined and converted to log10. The effect of treatment group on bacterial counts was made using Wilcoxon Rank Sums Test. One sample per group was scored and split for confocal imaging. Null Hypothesis: Teeth treated with EMS in combination with 1.5-percent sodium hypochlorite or 0.9-percent saline will not demonstrate a significant anti-biofilm effect in comparison to those treated with 6.0-percent sodium hypochlorite alone. Results: 0.9-percent saline and 0.9-percent saline with EMS were significantly higher than 6.0-percent NaOCl, 1.5-percent NaOCl, and 1.5-percent NaOCl with EMS. 0.9-percent saline was significantly higher than 0.9-percent saline with EMS. The three groups that included treatment with NaOCl were not significantly different from each other. Confocal imaging confirmed the CFU findings. Conclusion: Because there was no growth in any of the NaOCl groups, the null hypothesis cannot be rejected. However, there was an antibiofilm effect when comparing the two saline groups, demonstrating that EMS has an antibiofilm effect. Future studies should focus on determining what concentration of NaOCl is most effective in combination with EMS.

Indiana University-Purdue University Indianapolis (IUPUI) / Introduction: One of the main objectives of endodontic therapy is to reduce microbes and remove inflamed pulpal tissue within the root canal system (RCS). This is accomplished through chemomechanical debridement of the RCS using hand and rotary instrumentation along with an antimicrobial irrigant. Today, the most commonly used irrigant is sodium hypochlorite (NaOCl), often at concentrations toxic to human cells. The use of ozone as an endodontic irrigant is a novel technique that has been proven to be antimicrobial against several microorganisms. However, independent research is lacking on ozone’s efficacy against an established endodontic biofilm. If ozone’s efficacy against biofilms is confirmed, the use of toxic and potentially dangerous sodium hypochlorite could be replaced in some clinical situations (i.e., regeneration, immature teeth, resorption) with a safer and effective alternative. Objective: The aim of the current study was to evaluate the anti-biofilm activity of different concentrations of ozonated water compared to various concentrations of NaOCl against an established endodontic biofilm of Enterococcus faecalis in root canal treated teeth in vitro. Materials and Methods: The crowns of similarly sized, maxillary anterior teeth were removed, and the roots cut to a standard length (12 mm). All root canals were instrumented to a standard size. Specimens were sterilized and then inoculated with E. faecalis, which were allowed to grow for two weeks to form an established biofilm. There were six treatment groups: 1) 6% NaOCl; 2) 1.5% NaOCl; 3) 16µg/mL ozonated water; 4) 25µg/mL ozonated water; 5) 50µg/mL ozonated water, and 6) saline. Following treatment, samples were collected, plated, and incubated for two days. The number of CFU/mL were determined, and samples visualized using confocal imaging. The effect of treatment group on bacterial counts was made using one-way ANOVA followed by pair-wise comparisons. Null Hypothesis: Endodontically treated teeth irrigated with ozonated water will not demonstrate a statistically significant decrease in the E. faecalis biofilm compared to those treated with sodium hypochlorite Results: CFUs were converted to log10 and compared using Fisher’s Exact tests or one-way ANOVA followed by pair-wise tests. In all observations utilizing NaOCl irrigation, no colonies formed following treatment. The two NaOCl groups, with 0 CFU/mL, were significantly different than the other four groups (p=0.009). Saline showed a trend towards higher CFU/mL than 50 µg/ml O3 (p=0.068). None of the other comparisons approached statistical significance (p=0.453 25 µg/ml O3, p=0.606 16 µg/ml O3, p=0.999 25 µg/ml O3 vs 50 µg/ml O3, p=0.990 16 µg/ml O3 vs 50 µg/ml O3, p=1.000 16 µg/ml O3 vs 25 µg/ml O3). Confocal imaging helped illustrate effects of irrigation and confirm CFU findings. Conclusion: The results of this study failed to reject the null hypothesis. There was a statistically significant difference in the E. faecalis biofilm remaining in the groups treated with ozonated water compared to those treated with NaOCl. However, there was a trend towards higher CFU/mL in the saline group compared to the 50µg/mL ozonated water group. According to this finding, future studies should evaluate the effects of higher concentrations of ozonated water against an established E. faecalis biofilm. In addition, other follow-up studies might include ozonated water’s effect on human cells, such as the stem cells of the apical papilla that are so critical to the success of regenerative endodontic procedures. Due to university and laboratory closures caused by the COVID-19 pandemic, this project was stopped short and an insufficient sample size did not allow for proper statistical power. Additional occasions should be run upon the university’s re-opening to allow for proper statistical power.