Physicochemical Processes of Biofilm Formation on The Surface of Structures in Water / 生物化学与生物物理进展

Microorganisms can form biofilms, complex, heterogeneous, multicellular communities that adhere to surfaces. Biofilm formation on the surface of structures in water will accelerate structures’ corrosion, seriously affect their service efficiency and life, and significantly impact the growth of animals, plants, and human life. Hence, clarifying the mechanism of biofilm formation contributes to developing new strategies to control biofilm formation on surface and then reduce infections, biofouling, and contaminations. Biofilm-targeting strategies include the regulation of established biofilms or the modulation of single-cell attachment. In most studies, physicochemical mechanism is frequently applied to explain the initial bacterial adhesion phenomena but rarely to explain other stages of biofilm formation. This review presents a five-step comprehensive description of the physicochemical process from film formation to biofilm maturation: (1) period of film formation; (2) period of bacterial adhesion; (3) period of extracellular-polymeric-substances (EPSs) membrane formation; (4) period of regulating biofilm by quorum sensing (QS); (5) period of biofilm maturation. We first clarify how the film formed by compound molecules affects the surface’s physicochemical properties and initial adhesion, summarizing many factors that affect bacterial adhesion. We then review the types of EPSs and signal molecules secreted by bacteria after irreversible adhesion, as well as their role and QS mechanism in biofilm maturation. Finally, we discuss how bacteria or microcolonies separate from the mature biofilm by physicochemical action and summarize the morphology and adhesion characterization methods after the biofilm matures. This review redefines the role of physicochemical in the whole process of biofilm formation and provides a theoretical basis for the prevention, removal, and utilization of biofilm and other related research fields.

Research progress on the dentin adhesion of Enterococcus faecalis and its influencing factors / 口腔疾病防治

@#Enterococcus faecalis is the main pathogen causing refractory apical periodontitis (RAP). This bacterium can tolerate harsh environments and trigger periapical immune inflammatory responses that result in persistent infection inside and outside the root canal. Adhesion to the dentin wall of root canals and the subsequent formation of biofilms significantly enhances the drug resistance and anti⁃erosion ability of Enterococcus faecalis, which is the key factor medi⁃ ating its pathogenesis. The adhesion of Enterococcus faecalis to dentin involves non⁃specific adhesion and specific adhe⁃ sion, and the latter is mediated by adhesion⁃related virulence factors, mainly including the adhesin of collagen from en⁃terococci (Ace), extracellular surface protein (Esp), gelatinase (GelE), serine protease (SprE), endocarditis and biofilm associated pilus (Ebp) and aggregation substance (AS), which is regulated by multiple two⁃component systems. The two⁃ component system Fsr can promote the expression of gelE and sprE when the cell population density increases. GelE can further reduce Ace, while the two⁃component system GrvRS directly downregulates ace expression in response to the serum environment. The two⁃component systems CroRS and WalRK may also promote and inhibit the expression of vari⁃ ous virulence factors, including ace and gelE, thus affecting the adhesion of Enterococcus faecalis. In addition, the mech⁃ anochemical preparation and the internal environment of the root canal can also influence the adhesion of Enterococcus faecalis to dentin. Avoiding the introduction of Enterococcus faecalis and using adhesion⁃interfering medications during root canal treatment can effectively prevent the adhesion of Enterococcus faecalis, and a variety of activated irrigation protocols can also be effective at increasing the clearance of Enterococcus faecalis from the root canal. The design of ra⁃ tional drugs targeting key factors involved in and regulators of the adhesion of Enterococcus faecalis to dentin is expected to provide new ideas and strategies for root canal infection control. The present paper reviews the adhesion of Enterococ⁃ cus faecalis to dentin and its influencing factors.

Gene de virulência oipA de Helicobacter pylori como marcador molecular de gastropatias severas / Helicobacter pylori oipa virulence gene as a molecular marker of severe gastropathies

ABSTRACT Background: Helicobacter pylori is an etiologic agent of gastroduodenal diseases. The microorganism, considered a type I carcinogen, affects about 50% of the global population. H. pylori virulence factors are determinant for the clinical outcome of the infection. The outer inflammatory protein A (oipA) gene encodes an outer membrane adhesin and is related to severe gastropathies, such as gastric cancer. Objective: The aim of this study was to evaluate the association of the oipA gene with the severity of gastroduodenal diseases in dyspeptic patients in region Central Brazil. Methods: The polymerase chain reaction (PCR) was used to determine the presence of H. pylori. Samples positives were used for molecular screening of the oipA gene. Gastropathies were categorized as non-severe and severe diseases. Results: Approximately 68% of patients had H. pylori and 36% were infected with H. pylori oipA+ strains. Infection was significantly associated in patients aged over 44 years (P=0.004). However, there was no association between oipA and patients' age (P=0.89). Approximately 46% of patients infected with oipA+ strains had some severe illness. Gastric adenocarcinoma was the most frequent severe gastropathy. The H. pylori oipA genotype was inversely associated with the severity of gastroduodenal diseases (OR=0.247, 95%CI: 0.0804-0.7149 and P=0.007). Conclusion: The characterization of possible molecular markers will contribute to personalized medicine, impacting the prognosis of patients.

RESUMO Contexto: Helicobacter pylori é um agente etiológico de doenças gastroduodenais. O microrganismo, considerado cancerígeno tipo I, afeta cerca de 50% da população mundial. Os fatores de virulência do H. pylori são determinantes para o desfecho clínico da infecção. O gene da proteína inflamatória externa A (oipA) codifica uma adesina da membrana externa e está relacionado a gastropatias severas, como o câncer gástrico. Objetivo: O objetivo deste estudo foi avaliar a associação do gene oipA com a gravidade das doenças gastroduodenais em pacientes dispépticos na região Brasil Central. Métodos: A reação em cadeia da polimerase (PCR) foi utilizada para determinar a presença de H. pylori. Amostras positivas foram utilizadas para triagem molecular do gene oipA. As gastropatias foram categorizadas como doenças não severas e severas. Resultados: Aproximadamente 68% dos pacientes apresentaram H. pylori e 36% estavam infectados com cepas H. pylori oipA+. A infecção foi significativamente associada em pacientes com idade superior a 44 anos (P=0,004). No entanto, não houve associação entre oipA e a idade dos pacientes (P=0,89). Aproximadamente 46% dos pacientes infectados com cepas oipA+ tiveram alguma doença severa. O adenocarcinoma gástrico foi a gastropatia severa mais frequente. O genótipo oipA de H. pylori foi inversamente associado à gravidade das doenças gastroduodenais (OR=0,247, IC95%: 0,0804-0,7149 P=0,007). Conclusão: A caracterização de possíveis marcadores moleculares contribuirá para a medicina personalizada, impactando no prognóstico dos pacientes.

Expression and purification of a peptide fragment of 660 - 1468 amino acids in Neisseria gonorrhoeae NGO2105 protein as well as preparation and identification of its polyclonal antibody / 中华皮肤科杂志

Objective:To prokaryotically express a peptide fragment of 660 - 1468 amino acids in Neisseria gonorrhoeae NGO2105 protein, and to prepare and identify its polyclonal antibody. Methods:The pCold TF-NGO2105 660-1468 aa recombinant plasmid was transformed into the bacterium Escherichia coli BL21 (DE3) for protein expression. After the inclusion body protein was denatured and renatured, the target protein was purified. Then, BALB/c mice were immunized with the target protein to prepare a polyclonal antiserum; the antibody potency was evaluated by enzyme-linked immunosorbent assay, the specificity of the antibody against NGO2105 protein in Neisseria gonorrhoeae was analyzed by Western blot analysis, the affinity of the antiserum with Neisseria gonorrhoeae was analyzed by flow cytometry, and adhesion inhibition assay was performed to evaluate the inhibitory effect of anti-NGO2105 660-1468 aa antibody on the adhesion of Neisseria gonorrhoeae to human cervical epithelial ME-180 cells. Comparisons between different groups were performed by using t test. Results:The NGO2105 660-1468 aa protein was expressed as the inclusion body, and the soluble target protein was obtained by denaturation, renaturation, and purification. After immunization of mice with the target protein, the antiserum titer was 5.12 × 10 6, and flow cytometry showed that the antibody bound well to the Neisseria gonorrhoeae NGO2105 660-1468 aa. Adhesion inhibition assay showed that the anti-NGO2105 660-1468 aa antibody significantly inhibited the adhesion of Neisseria gonorrhoeae to ME-180 cells, and the inhibitory effect was concentration-dependent to some extent, with the adhesion rates of Neisseria gonorrhoeae treated with 20- and 40-fold dilutions of the anti-NGO2105 660-1468 aa antibody being 52.9% and 79.2% respectively, significantly lower than the adhesion rate in the untreated group (100%, t = 8.40, 5.29, P < 0.001, = 0.006, respectively) . Conclusion:The NGO2105 660-1468 aa protein was successfully expressed and purified, and a highly potent polyclonal antibody was prepared, which had a good affinity with Neisseria gonorrhoeae and an adhesion inhibition ability.

Effect of gastric acid on the surface roughness and bacterial adhesion of bulk-fill composite resins

Abstract The purpose of this in vitro study was to evaluate the effect of gastric acid on the surface roughness and biofilm formation of bulk-fill composite resins. Twenty-seven samples of each composite resin were obtained: G1: Filtek Z250 XT (Z250), G2: Filtek Bulk Fill (FTK), G3: Tetric N-Ceram Bulk Fill (TTC), and G4: Aura Bulk Fill (AUR). The samples were quantitatively analyzed for surface roughness (Ra) using a roughness tester (n=15) and for biofilm formation (Cn) by the counting of colony-forming units (CFUs/mL) (n=9) in three different moments: after polishing (Ra0 and Cn0), after gastric acid immersion (Ra1 and Cn1), and after gastric acid and simulated tooth brushing (Ra2 and Cn2). Qualitative analysis through surface topography (n=3) was evaluated by scanning electron microscopy (SEM). Ra values were subjected to two-way repeated measures ANOVA, followed by Tukey's test. Cn values were subjected to Kruskal-Wallis analysis, followed by multiple comparisons analysis (α=0.05). Z250 and FTK showed significant increases in surface roughness at Ra1. There were fewer CFUs/mL on TTC and AUR in relation to those of Z250 and FTK for Cn0, Cn1 and Cn2. The SEM images showed that gastric acid increased the formation of cracks, exposure of fillers and micro cavities for all composite resins. After tooth brushing, the topographical changes were more evident but did not influence biofilm formation. The gastric acid promoted both degradation of the surfaces and bacterial adhesion for all composite resins.

Resumo O objetivo deste estudo in vitro foi avaliar o efeito do ácido gástrico na rugosidade superficial e na formação do biofilme nas resinas compostas de incremento único. Vinte e sete amostras de cada resina composta foram confeccionadas: G1: Filtek Z250 XT (Z250), G2: Filtek Bulk Fill (FTK), G3: Tetric N-Ceram Bulk Fill (TTC), and G4: Aura Bulk Fill (AUR). As amostras foram analisadas quantitativamente quanto à rugosidade da superfície (Ra) usando um rugosímetro (n=15) e para formação de biofilme (Cn) pela contagem de unidades formadoras de colônias (UFC/mL) (n=9) em três diferentes momentos: após polimento (Ra0 and Cn0), após imersão em ácido gástrico (Ra1 and Cn1), e após ácido gástrico e simulação de escovação (Ra2 and Cn2). Análise qualitative da topografia superficial (n=3) foi avaliada por meio de microscopia eletrônica de varredura (MEV). Os valores de Ra foram analisados pela ANOVA de duas vias para amostras pareadas, seguido do teste de Tukey. Os valores de Cn foram submetidos ao teste de Kruskal-Wallis, seguido da análise de comparações múltiplas (α=0,05). Z250 e FTK tiveram aumento significativo na rugosidade superficial em Ra1. Houve menos CFUs/mL para TTC e AUR em relação à Z250 e FTK em Cn0, Cn1 and Cn2. As imagens em MEV mostraram que o ácido gástrico aumentou a formação de fendas, exposição das partículas e mcrocavidades para todas as resinas compostas. Após escovação, as mudanças topográficas foram mais evidentes, mas não influenciou na formação do biofilme. O ácido gástrico promoveu degradação da superfície e adesão bacteriana para todas as resinas compostas.

Factores relacionados con el abandono de la suplementación de los micronutrientes en niños / Factors related to the abandonment of micronutrient supplementation in children / Fatores relacionados ao abandono da suplementação de micronutrientes em crianças

La anemia es uno de los problemas más importantes de la salud pública, viéndose un crecimiento sostenido en los últimos años. Existen diversos factores relacionados al abandono de la suplementación de los micronutrientes. Objetivo. Establecer los factores relacionados con el abandono de la suplementación de los micronutrientes en niños de 6 a 36 meses atendidos en un Centro Materno Infantil. Materiales y métodos. El enfoque fue cuantitativo, de tipo básica, diseño no experimental transversal. La población estuvo constituida por 120 pacientes neonatos y la muestra fue de 80 pacientes neonatos del Centro Materno infantil, elegidos mediante muestreo no probabilístico, con la técnica de la encuesta y el instrumento fue el cuestionario. Resultados. El 25% presentó niveles inadecuados, el 62.5% presentó niveles moderados y el 12.5% presentó niveles adecuados de uso de suplementación de los micronutrientes. Conclusiones. El abandono de la suplementación de los micronutrientes se encuentra asociado con los factores generales del infante, como la edad, sexo, y número de hijo, tipo de seguro y número de micronutriente y además dependen de los factores relacionados al cuidador a edad del cuidador, grado de instrucción, estado civil, número de hijos, procedencia y ocupación, tal como muestra al prueba de la independencia de Chi-cuadrado y el p< 0.05, y se establecen que los factores generales del niño y los Factores relacionados al cuidador se encuentran asociados en la suplementación de los micronutrientes.

Anemia is one of the most important public health problems, with a sustained growth in recent years. There are several factors related to the abandonment of micronutrient supplementation. Objective. To establish the factors related to the abandonment of micronutrient supplementation in children aged 6 to 36 months attended in a Maternal and Child Center. Materials and methods. The approach was quantitative, basic, non-experimental cross-sectional design. The population consisted of 120 neonatal patients and the sample consisted of 80 neonatal patients of the Maternal and Child Center, chosen by non-probabilistic sampling, with the survey technique and the instrument was the questionnaire. Results. The 25% presented inadequate levels, 62.5% presented moderate levels and 12.5% presented adequate levels of micronutrient supplementation. Conclusions. The abandonment of micronutrient supplementation is associated with the general factors of the infant, such as age, sex, and number of children, type of insurance and number of micronutrients and also depend on the factors related to the caregiver such as age of the caregiver, education level, marital status, number of children, origin and occupation, as shown by the Chi-square test of independence and p< 0.05, and it is established that the general factors of the child and the factors related to the caregiver are associated in the supplementation of micronutrients.

A anemia é um dos mais importantes problemas de saúde pública, com um aumento constante nos últimos anos. Há vários fatores relacionados ao descaso com a suplementação de micronutrientes. Objetivo. Estabelecer os fatores relacionados ao abandono da suplementação de micronutrientes em crianças de 6 a 36 meses de idade que freqüentam um Centro Mãe e Criança. Materiais e métodos. A abordagem foi quantitativa, básica e não-experimental, de corte transversal. A população consistia de 120 pacientes neonatais e a amostra consistia de 80 pacientes neonatais do Centro Materno e Infantil, escolhidos por amostragem não-probabilística, utilizando a técnica de pesquisa e o questionário como instrumento. Resultados. 25% apresentaram níveis inadequados, 62,5% apresentaram níveis moderados e 12,5% apresentaram níveis adequados de suplementação de micronutrientes. Conclusões. O abandono da suplementação de micronutrientes está associado aos fatores gerais da criança, tais como idade, sexo e número de crianças, tipo de seguro e número de micronutrientes e também depende dos fatores do cuidador relacionados à idade do cuidador, nível de educação, estado civil, número de crianças, origem e ocupação, como demonstrado pelo teste de independência Qui-quadrado e p< 0,05, e é estabelecido que os fatores gerais da criança e os fatores do cuidador estão associados na suplementação de micronutrientes.

The effect of coconut sugar on cariogenic traits in Streptococcus mutans / Efeito do Açúcar de Coco na cariogenicidade do Streptococcus mutans

Aim: The consumption of foods rich in sugar is linked to several non-communicable diseases, including dental caries. Coconut sugar has systemic benefits due to its lower glycemic indexes (GI) than other table sugars. However, there is currently no data regarding its ca-riogenic potential. This study aimed to evaluate the effect of coconut sugar on acidogenicity and adhesion of Streptococcus mutans in vitro, compared to sugarcane products. Materials and methods: Aliquots of cultu-res of S. mutans UA159 were resuspended in a buffer solution enriched with coconut sugar, crystal sugar (refined sugar), and minimally processed sugarcane (demerara light brown sugar and maskavo dark brown sugar), as well as positive (sucrose) and negative con-trols. The decrease in pH and its corresponding area under the curve (AUC; cm2) were evaluated for the analysis of acidogenicity. S.mutans was incubated in BHI supplemented with each sugar and the percentages of microbial adhesion were calculated. After testing data normality, the one-way ANOVA test (Bonferroni post hoc) was used to compare the AUC and the pro-portion of adhesion of each group. Results: Regarding the acidogenic potential, statistical differences were found only between the negative control versus all other groups (p<0.001). Likewise, no significant difference in adhesion was found between the tested sugars (p>0.05). Discussion: Although the tested sugars are marketed as "healthy products," their amount and frequency of usage should be controlled. Conclusion: Coconut su-gar presents a similar cariogenic potential to that of sugarcane products when acidogenicity and adhesion are evaluated. Coconut sugar is not indicated as a substitute for sucrose in the control of cariogenic activity.

Objetivo: O consumo de alimentos ricos em açúcar está associado a diversas doenças não transmissíveis, incluindo a doença cárie. O açúcar de coco tem benefícios sistêmi-cos devido aos seus índices glicêmicos (IG) mais baixos do que outros açúcares de mesa. No entanto, atualmente não há dados sobre seu potencial cariogênico. Esse estu-do teve como objetivo avaliar o efeito do açúcar do coco na acidogenicidade e adesão de Streptococcus mutans in vitro, em comparação com produtos derivados da cana--de-açúcar. Materiais e métodos: alíquotas de culturas de S. mutans UA159 foram suspensas em solução tampão enriquecida com açúcar de coco, açúcar cristal (açúcar refinado) e cana-de-açúcar minimamente processada (açúcar mascavo demerara claro e açúcar mascavo), além de controles positivo (sacarose) e negativo. A diminuição do pH e correspondente área sob a curva (AUC; cm2) fo-ram avaliadas na análise de acidogenicidade. S. mutansfoi incubado em BHI suplementado com cada tipo de açúcar e as porcentagens de adesão microbiana foram calculadas. Após testar a normalidade dos dados, o teste ANOVA de uma via (Bonferroni post hoc) foi utilizado para comparar a AUC e a proporção de adesão de cada grupo. Resultados: Em relação ao potencial acidogênico, diferenças estatísticas foram encontradas apenas entre o controle negativo versus todos os outros grupos (p <0,001). Não foi encontrada diferença significativa na adesão en-tre os açúcares testados (p> 0,05). Discussão: Apesar dos açúcares testados serem comercializados como "produtos saudáveis", sua quantidade e frequência de consumo deve ser controlada. Conclusão: O açúcar do coco apresenta potencial cariogênico semelhante à dos produtos da cana-de-açúcar quanto a acidogenicidade e a adesão. O açúcar de coco não é indicado como substituto da sacarose no controle da atividade cariogênica.

An in vitro evaluation of surface roughness, color stability and bacterial accumulation of lithium disilicate ceramic after prophylactic periodontal treatment / Avaliação in vitro da rugosidade superficial, estabilidade de cor e acúmulo bacteriano em cerâmica de dissilicato de lítio após tratamento de profilaxia periodontal

Objective: To evaluate the effect of scaling procedures using different ultrasonic tips on the surface roughness, color stability and bacterial accumulation of lithium disilicate ceramic. Material and Methods: Scaling procedure was carried out using ultrasonic scaler (Satalec, Acteon, North America) with stainless-steel tip (US), titanium tip (UT) and plastic tip (UP), on disc shaped lithium disilicate samples cemented into a cavity prepared onto the labial surface of freshly extracted bovine teeth (10 samples per group). The samples were stored in coffee solution in an incubator at 37°C for 12 days, which is equivalent to 1 year of coffee consumption. The surface roughness was measured before and after the scaling procedure using a profilometer and atomic force microscopy. The color parameters were measured before and after scaling and staining procedures using VITA Easyshade Advance 4.0 according to the CIE L*a*b* color order system. The samples were then incubated with Streptococcus mutans (S. mutans) suspension. After incubation, the plates with 30 to 300 typical colonies of S. mutans were counted in a colony counter and mean values of colony forming units were obtained (CFU/mL). Results:The titanium scaling tip showed a statistically significant higher mean values of change in surface roughness ΔRa and bacterial count than the plastic scaling tip. Color changes (ΔE) were not a statistically significant among the groups. The results showed a statistically significant positive (direct) correlation between surface roughness and color change (p = 0.012) and also between surface roughness and bacterial count (p = 0.00). Conclusion: Within the limitations of this study, titanium scaling instruments cause irreversible surface alterations of lithium disilcate ceramics which was in direct correlation to the color changes and bacterial accumulation; therefore, dentists should proceed with caution when scaling lithium disilicate surfaces. The findings of the current study may indicate the need for instruments or equipment that can remove plaque and calculus without causing surface damage (AU)

Introdução: Avaliar o efeito de procedimentos de raspagem com diferentes pontas de ultrassom na rugosidade superficial, estabilidade de cor e acúmulo bacteriano em cerâmica de dissilicato de lítio. Material e Métodos: O procedimento de raspagem foi realizado usando um aparelho de ultrassom (Satalec, Acteon, América do Norte) com ponta de aço inoxidável (US), ponta de titânio (UT) e ponta de plástico (UP), em amostras de dissilicato de lítio em forma de disco cimentadas em uma cavidade preparada na superfície vestibular de dentes bovinos recém-extraídos (10 amostras por grupo). As amostras foram armazenadas em solução de café em incubadora a 37 ° C por 12 dias, o que equivale a 1 ano de consumo de café. A rugosidade da superfície foi medida antes e após o procedimento de raspagem usando um perfilômetro e um microscópio de força atômica. Os parâmetros de cor foram medidos antes e depois dos procedimentos de raspagem e armazenagem no café usando VITA Easyshade Advance 4.0 de acordo com o sistema de ordem de cores CIE L*a*b*. As amostras foram incubadas com suspensão de Streptococcus mutans (S. mutans). Após a incubação, as placas com 30 a 300 colônias típicas de S. mutans foram contadas em contador de colônias e obtidos os valores médios das unidades formadoras de colônias (UFC / mL). Resultados: A ponta de titânio mostrou valores estatisticamente maiores de mudança na rugosidade da superfície ΔRa e contagem de bactérias do que a ponta de raspagem de plástico. A mudança de cor (ΔE) não foi estatisticamente significativa entre os grupos. Os resultados mostraram uma correlação positiva (direta) estatisticamente significativa entre rugosidade superficial e alteração de cor (p = 0,012) e também entre rugosidade superficial e contagem bacteriana (p = 0,00). Conclusão: Dentro das limitações deste estudo, os instrumentos de raspagem de titânio causam alterações irreversíveis na superfície das cerâmicas de dissilicato de lítio que estão em correlação direta com as mudanças de cor e o acúmulo de bactérias. Portanto, os dentistas devem proceder com cautela ao realizar raspagem em superfícies de dissilicato de lítio. Os resultados deste estudo podem indicar a necessidade de instrumentos ou equipamentos que possam remover a placa e cálculo sem causar danos à superfície. (AU)

Photo Catalytic Silver Modified Orthodontic Brackets - An Innovative Method for Prevention of White Spot Lesions

Association between fixed orthodontic therapy and enamel decalcification causing periodontal disease and enamel decalcification is a known problem of orthodontic treatment. The root cause of this is the fact that brackets provide an ideal environment for bacteria to accumulate and multiply. Hence modifying the surface of brackets with some photocatalytic antibacterial substance could help in prevention of this side-effect. The current study was thus planned to evaluate the anti-adherence of bacteria to photocatalytic silver coated brackets for the prevention of white spot lesions. METHODSAfter obtaining ethical clearance from the institutional ethics committee, 40 metal brackets of upper central incisor were taken. These brackets were divided into group 1 & group 2 each containing twenty brackets. Group 1 (control group) consisted of plain metal brackets while group 2 (experimental group) consisted of silver coated brackets. Both the groups were subjected to laboratory bacterial tests to assess the bacterial adhesion to brackets and then statistical analysis was done to obtain results. RESULTSSilver modified brackets showed around 25 % less adhesion of bacteria as compared with plain brackets. CONCLUSIONSModifying orthodontic brackets by coating them with photocatalytic silver could prove to be an innovative and effective method in prevention of white spot lesions after fixed orthodontic therapy.

Influência da adesão bacteriana em resina composta Bulk fill submetida a diferentes protocolos de acabamento e polimento: estudo in vitro / Influence of bacterial adhesion on Bulk fill composite resin submitted to different finishing and polishing protocols: in vitro study

Objetivo: avaliar a adesão bacteriana do Streptococcus mutans na superfície de uma resina composta do tipo incremento único submetida a diferentes protocolos de polimento. Materiais e métodos: foram realizadas 60 amostras nas quais foram divididas aleatoriamente em 6 grupos (n=10) de diferentes tratamentos de superfície. Cinco amostras de cada grupo foram separadas e submetidas ao estudo de adesão bacteriana, das quais duas foram analisadas pela microscopia eletrônica de varredura. Foram contabilizadas as unidades formadoras de colônias UFC/ml de modo manual e realizada a média e desvio padrão de cada grupo. De acordo com os resultados analisados através do teste de One Way ANOVA e comparações múltiplas de Tukey observou-se uma diferença estatisticamente significativa entre os grupos. Resultados: os valores de UFC/ mL variaram de 0 para o grupo American Burrs a 8,64 para o grupo Dhpro. Os grupos Jota e Dhpro não diferiram estatisticamente entre si (p=0,71), porém diferiram dos demais grupos avaliados (p=0,45). Os grupos American Burrs e o controle negativo não diferiram estatisticamente entre si (p>0.999) e diferiram dos demais grupos testados (p=0,20). O grupo de controle positivo diferiu estatisticamente dos outros grupos (p=0,02) assim como o grupo KG (p=0,01). Conclusão: Diante dos resultados obtidos, pode-se concluir que, a superfície da resina Bulk Fill One submetida a diferentes protocolos de polimento e mesmo sem ter passado por nenhum tratamento de superfície é passível de adesão bacteriana seja por contagem manual ou microscopia eletrônica de varredura(AU)

Objective: To evaluate the bacterial adhesion of Streptococcus mutans on the surface of a single increment composite resin submitted to different polishing protocols. Materials and methods: 60 samples were randomly divided into 6 groups (n = 10) of different surface treatments. Five samples from each group were separated and submitted to the bacterial adhesion study, two of which were analyzed by scanning electron microscopy. The UFC/ml colony forming units were accounted for manually and the mean and standard deviation of each group were performed. According to the results analyzed by the One Way ANOVA test and Tukey's multiple comparisons, a statistically significant difference was observed between the groups. Results: The values ranged from 0 for the American Burrs group to 8.64 for the Dhpro group. The Jota and Dhpro groups did not differ statistically (p = 0.71), but differed from the other groups evaluated (p = 0.45). The American Burrs and negative control groups did not differ statistically (p> 0.999) and differed from the other groups tested (p = 0.20). The positive control group differed statistically from the other groups (p = 0.02) as did the KG group (p = 0.01). Conclusion: It can be concluded that the surface of the Bulk Fill One resin submitted to different polishing protocols and even without any surface treatment is susceptible to bacterial adhesion either by manual counting or scanning electron microscopy(AU)

Research progress on factors affecting bacterial adhesion on the oral implant surface / 口腔疾病防治

@#Reducing the adhesion of microorganisms and the formation of biofilms on implant surfaces can prevent peri-implant inflammation and optimize the long-term prognosis of implanted dentures. To provide theoretical support for the development of new materials or the modification of existing materials and the improvement of the success rate of implant repair, a literature review was conducted, which shows that the factors influencing bacterial adhesion on dental implant surfaces included the type of implant material, material roughness, nonspecific physical and chemical properties, the type of antibacterial coating, the components of the acquired membrane on the implant surface, the structure of the bacterial cell wall, etc. The current research direction of implant materials aims to reduce bacterial adhesion and promote bone bonding. However, there is no consensus on the physical and chemical properties of implants that meet this requirement. At present, the development trend in implant materials is guided by research of the “core microbiome” of peri-implant inflammation, based on study of the factors related to the adhesion of pathogenic microorganisms to the implant surface, which is organically combined with a variety of modification methods to change the surface-related properties of the implant materials and even to endow the implant with antibacterial properties to reduce or inhibit the adhesion of pathogenic bacteria to the implant.

"Amar" el índice de O'Leary / The O'Leary index, a.k.a. the "Love" index

La detección y cuantificación de placa dental bacteriana se considera básica en la práctica de la estomatología. El índice O'Leary constituye una herramienta sencilla que mide la cantidad de placa dental bacteriana en los dientes, y resulta uno de los más efectivos en la evaluación de la higiene bucal. La connotación que tiene la higiene bucal en varias esferas de la vida quizás llevó a que este índice fuera bautizado en Cuba como índice de Love (Amor); por lo que nos proponemos esclarecer la conveniencia del empleo de la denominación internacional de este(AU)

Detection and quantification of bacterial dental plaque is considered to be crucial in dental practice. The O'Leary index is a simple tool to measure the amount of bacterial dental plaque on teeth and one of the most effective means to evaluate oral hygiene. The connotation of oral hygiene in several spheres of life is probably the reason why this index is also known in Cuba as the Love Index. We intend to shed light on the advisability of using the international term(AU)

Adhesión Bacteriana en Hilo de Sutura de Seda Negra y Nylon Post Extracción Dental Simple: Ensayo Clínico Controlado / Bacterial Adhesion in Black Silk Suture Thread and Nylon Post Simple Dental Extraction: Controlled Clinical Trial

RESUMEN: El objetivo de este estudio fue comparar los hilos de sutura de seda negra y la sutura nylon con respecto a la adhesión bacteriana post extracción dental simple de piezas posteriores. El presente trabajo se desarrolló en la Clínica Odontológica y el Laboratorio de Microbiología de la Unidad de Ciencias Biomédicas y Biotecnología de la Universidad Privada Antenor Orrego (Trujillo, Perú), entre agosto y setiembre de 2014. Se trabajó con 19 unidades de muestreo para hilo de seda negra y 19 para nylon. El procedimiento de exodoncia para todos los pacientes fue estandarizado. Luego de la extracción, se procedió a suturar la herida quirúrgica, colocando dos puntos circunferenciales, uno con cada tipo de hilo. A los 7 días, los hilos fueron retirados y sometidos a análisis microbiológico. La adhesión bacteriana de los hilos de sutura seda negra y nylon fue comparada empleando el test de Wilcoxon. Además la adhesión bacteriana de cada hilo fue comparada con la adhesión en hilos estériles (control) empleando el test de Mann-Whitney para una p<0,005. Al comparar la adhesión bacteriana de ambos hilos, se encontró diferencia entre ellos (p=0,027), correspondiendo mayor adhesión al hilo de nylon. La adhesión bacteriana fue mayor en el hilo de sutura de nylon comparado con el hilo de sutura de seda negra.

ABSTRACT: The objective of the study was to compare black silk suture threads and nylon suture with respect to bacterial adhesion after simple dental extraction of posterior pieces. The present study was developed in the Clínica Estomatológica and the Laboratorio de Microbiología of the Unidad de Ciencias Biomédicas y Biotecnología de la Universidad Privada Antenor Orrego (Trujillo, Peru), between August and September 2014. We worked with 19 units sampling for black silk thread and 19 for nylon. The procedure of exodontia for all patients was standardized. After the extraction, the surgical wound was sutured, placing two circumferential points, one with each type of thread. After 7 days, the threads were removed and subjected to microbiological analysis. The bacterial adhesion of the black silk and nylon suture strands was compared using the Wilcoxon test. In addition, the bacterial adhesion of each strand was compared with the adhesion in sterile strands (control) using the Mann-Whitney test for p <0.005. When comparing the bacterial adhesion of both threads, a difference was found between them (p = 0.027), corresponding greater adhesion to the nylon thread. Bacterial adhesion was higher in nylon suture compared to black silk suture.

Effects of different surface finishing protocols for zirconia on surface roughness and bacterial biofilm formation

PURPOSE: Surface finishing of a zirconia restoration is essential after clinical adjustment. Herein, we investigated the effects of a surface finishing protocol for monolithic zirconia on final roughness and bacterial adherence. MATERIALS AND METHODS: Forty-eight disk-shaped monolithic zirconia specimens were fabricated and divided into four groups (n = 12) based on initial surface treatment, finishing, and polishing protocols: diamond bur+polishing bur (DP group), diamond bur+stone grinding bur+polishing bur (DSP group), no diamond bur+polishing bur (NP group), and no diamond bur+stone grinding bur+polishing bur (NSP group). Initial and final surface roughness was measured with a profilometer, and shown using scanning electron microscope. Bacterial adhesion was evaluated by quantifying Streptococcus mutans in the biofilm. Kruskal-Wallis and Mann-Whitney U tests were used to compare results among groups, and two-way analysis of variance was used to evaluate the effects of grinding burs on final roughness (α=.05). RESULTS: The DP group had the highest final Ra value, followed by the DSP, NP, and NSP groups. Use of the stone grinding bur as a coarse-finishing step significantly decreased final Ra values when a diamond bur was used (P < .001). Omission of the stone grinding bur increased biofilm formation on specimen surfaces. Combining a stone grinding bur with silicone polishing burs produced the smallest final biofilm values, regardless of the use of a diamond bur in initial surface treatment. CONCLUSION: Coarse finishing of monolithic zirconia with a stone grinding bur significantly decreased final Ra values and bacterial biofilm formation when surfaces had been roughened by a diamond bur.

Effect of Lactobacillus delbrueckii fermented supernatant on Candida albicans biofilm formation / 中华检验医学杂志

Objective To investigate the effect of Lactobacillus delbrueckii fermented supernatant on Candida albicans biofilm and explore its possible mechanism and effective components.Methods Lactobacillus delbrueckii was isolated from vaginal Lactobacillus capsules (Ding Junsheng) and identified by mass spectrometer and sequencing.Lactobacillus delbrueckii fermented supernatant was prepared.The effect of Lactobacillus delbrueckii fermented supernatant on Candida albicans biofilm was tested by microplate crystal violet staining method and catheterization tube modeling method.Biofilm morphological changes were analyzed by crystal violet staining and Live/ Dead fluorescent dyes.Exopolysaccharides of Candida albicans biofilm was measured by the sulphruic acid-phenol method.The effect of Lactobacillus delbrueckii fermented supernatant on the adherence of Candida albicans biofilm was tested by the method of colony counting on plate.The fermented supernatant was treated with NaOH,catalase,typsin and proteinase K respectively.Then the treated fermented supernatant's effect on Candida albicans biofilm formation was detected.One-way ANOVA or Wilcoxon Rank Sum Test was used as statistical analysis for quantitative data.Results Lactobacillus delbrueckii was successful ly isolated and identified from Ding Junsheng.Lactobacillus delbrueckii fermented supernatant could significantly and dose-dependantly inhibited the formation of Candida albicans biofilm(F=10.804,P=0.000).The morphological changes showed that the fermented supernatant could decrease the formation of biofilm.When treated with Lactobacillus delbrueckii fermented supernatant,Candida albicans biofilm expolysaccharides was significantly inhibited (F=17.140,P=0.000) and adherence ability was reduced.Compared to untreated fermented supernatant (A490=0.486±0.112),the biofilm inhibition effect of fermented supernatant treated with NaOH (A490=0.675 ± 0.095),catalase(A490=0.577 ± 0.118),typsin(A490=0.600 ± 0.044) and proteinase K (A490-0.495±0.084)only decreased slightly,but when compared to the control group (A490=1.079 ± 0.158),the treated fermented supernatant still showed significant biofilm inhibition effect (x2=26.052,P=0.000),which suggested that the effective components of fermented supernatant were organic acid and bacteriocin-like substance.Conclusions Lactobacillus delbrueckii fermented supernatant can effectively inhibit Candida albicans biofilm formation.The action mechanisms are related with expolysaccharides decreasement and adherence reduction.The function components of fermented supernatant are possibly organic acids and bacteriocin-like substance.

An in vitro model of Fusobacterium nucleatum and Porphyromonas gingivalis in single- and dual-species biofilms

PURPOSE: The goal of this study was to develop and validate a standardized in vitro pathogenic biofilm attached onto saliva-coated surfaces. METHODS: Fusobacterium nucleatum (F. nucleatum) and Porphyromonas gingivalis (P. gingivalis) strains were grown under anaerobic conditions as single species and in dual-species cultures. Initially, the bacterial biomass was evaluated at 24 and 48 hours to determine the optimal timing for the adhesion phase onto saliva-coated polystyrene surfaces. Thereafter, biofilm development was assessed over time by crystal violet staining and scanning electron microscopy. RESULTS: The data showed no significant difference in the overall biomass after 48 hours for P. gingivalis in single- and dual-species conditions. After adhesion, P. gingivalis in single- and dual-species biofilms accumulated a substantially higher biomass after 7 days of incubation than after 3 days, but no significant difference was found between 5 and 7 days. Although the biomass of the F. nucleatum biofilm was higher at 3 days, no difference was found at 3, 5, or 7 days of incubation. CONCLUSIONS: Polystyrene substrates from well plates work as a standard surface and provide reproducible results for in vitro biofilm models. Our biofilm model could serve as a reference point for studies investigating biofilms on different surfaces.

Adhesion and Biofilm Formation Abilities of Bacteria Isolated from Dental Unit Waterlines / 치위생과학회지

The purpose of our study is to compare the adhesion and biofilm formation abilities of isolates from water discharged from dental unit waterlines (DUWLs). Bacteria were isolated from a total of 15 DUWLs. Twelve isolates were selected for the experiment. To confirm the adhesion ability of the isolates, each isolate was attached to a glass coverslip using a 12-well plate. Plates were incubated at 26℃ for 7 days, and the degree of adhesion of each isolate was scored. To verify the biofilm formation ability of each isolate, biofilms were allowed to form on a 96-well polystyrene flat-bottom microtiter plate. The biofilm accumulations of all isolates formed at 26℃ for 7 days were identified and compared. A total of 56 strains were isolated from 15 water samples including 12 genera and 31 species. Of the 56 isolates, 12 isolates were selected according to the genus and used in the experiment. Sphingomonas echinoides, Methylobacterium aquaticum, and Cupriavidus pauculus had the highest adhesion ability scores of +3 among 12 isolates. Among these three isolates, the biofilm accumulation of C. pauculus was the highest and that of S. echinoides was the third-most abundant. The lowest biofilm accumulations were identified in Microbacterium testaceum and M. aquaticum. Most isolates with high adhesion ability also exhibited high biofilm formation ability. Analysis of adhesion and biofilm formation of the isolates from DUWLs can provide useful information to understand the mechanism of DUWL biofilm formation and development.

Function of gene 0955 in Streptococcus suis type 2 98HAH33 / 中华微生物学和免疫学杂志

Objective To study the function of gene 0955 in Streptococcus suis type 2 98HAH33. Methods Growth condition of wild-type, mutant and complemented strains of Streptococcus suis type 2 98HAH33 was compared at different stages. Differences in adhesion ability to host cells and anti-phagocyto-sis among these strains were compared by using bacterial adhesion test and analyzing their survival rates in blood. Mouse and piglet models were used to evaluate their virulence. Results The growth of the mutant and the complemented strains was slightly slower than that of the wild type strains in logarithmic growth phase, but no significant difference was found in plateau phase. Bacterial adhesion test showed that gene 0955 might encode a new adhesion factor of Streptococcus suis type 2 98HAH33. Blood bactericidal test sug-gested that gene 0955 was not associated with anti-phygocytosis. Animal experiments showed that gene 0955 might be a novel virulence gene of Streptococcus suis type 2 98HAH33. Conclusion Gene 0955 might en-code a novel adhesion factor and virulence factor of Streptococcus suis type 2 98HAH33.

Surface topography and bacterial adhesion of CAD/CAM resin based materials after application of different surface finishing techniques

Aim: This study evaluated the surface topography and bacterial adhesion of a hybrid ceramic and a nano ceramic resin composite after different surface finishes. Methods: Hybrid ceramic (Vita Enamic, VITA - EN) and nano ceramic resin composite (Lava Ultimate, 3M/ESPE - LV) blocks of 12 x 14 x 18 mm were cut into 1 mm slices. Each slice was divided into four specimens (6 x 7 mm) that were randomly allocated into 4 groups (n=8) according to the surface finishing: CTL - without surface finish (control); DB - wear with a diamond bur; VT - polishing system for hybrid ceramic (VITA); and DD - polishing system for ceramics (Dedeco). The specimens were analyzed regarding surface roughness parameters (Ra, Rz, Rq), sterilized and subjected to bacterial adhesion. Representative specimens from each group were observed by SEM and Confocal Laser Scanning Microscopy. Data were submitted to two-way ANOVA and Tukey's test (α=0.05). Results: EN had lower surface roughness and bacterial adhesion than LV (p<0.05), regardless of the surface finish. The highest values for all roughness parameters was observed in LVDB group, differing from the other groups, which were not significantly different. Smaller bacterial adhesion values (CFU/mL) were observed for ENDD and ENVT, which differed significantly from the other groups, except ENCTL. For LV groups there was no significant difference between the different surface finishes (p>0.05). The type of material and surface finish system significantly interfered with surface roughness parameters and bacterial adhesion. The hybrid ceramic performed better after polishing than the nano-ceramic resin. Conclusion: An adequate finishing/polishing technique should always be performed after any kind of adjustment to indirect restorations made with these materials tested

Anti-adhesion potential of non-polar compounds and extracts from Ficus natalensis

Abstract Four triterpenoids, ergosta-4,6,8(14),22-tetraene-3-one 1, stigma-4-ene-3-one 2, 3β-hydroxy-21β-H-hop-22(29)-ene 3, sitosterol and a quinone, tectoquinone 4, were isolated from the leaf, stem bark and fruit extracts of Ficus natalensis subsp. natalensis, Moraceae, a medicinal fig found in Africa. The pure compounds 1-4 and crude extracts were tested for their antibacterial activity against five Gram-negative and seven Gram-positive strains and for their potential anti-biofilm activity. Antimicrobial susceptibility was observed with all pure compounds tested at 250 µg against the majority of Gram-negative and Gram-positive strains. The dichloromethane-soluble fruit extract was active against sensitive and resistant Staphylococcus aureus strains, Enterococcus faecalis and Staphylococcus xylosus. Compounds 2, 3 and 4 demonstrated broad-spectrum antibiotic effects against eight of the twelve bacterial strains tested. In the anti-biofilm assay, exposure to ethyl acetate, methanol and aqueous methanol leaf, stem bark and fruit extracts decreased adhesion with a biofilm reduction of ≥100% for all three tested organisms: Escherichia coli, Pseudomonas aeruginosa and S. aureus. The methanol leaf extract demonstrated the most potent anti-adhesion potential against E. coli (218% biofilm reduction). The greatest ability to decrease adhesion was observed with compounds 2, 3 and 5 against P. aeruginosa at the lowest concentration tested (100 µg ml−1).