Antimicrobial Activity of Compounds Containing Silver Nanoparticles and Calcium Glycerophosphate in Combination with Tyrosol.

Nanocomposites containing antimicrobial agents and calcium phosphates have been developed. Thus, this study assessed the effects of two compounds containing silver nanoparticles (AgNPs) and ß-calcium glycerophosphate (CaGP), associated or not with tyrosol (TYR), against planktonic cells and biofilms of Candida albicans and Streptococcus mutans. The nanocompounds were synthesized through chemical and 'green' processes and characterized by scanning electron microscopy. The minimum and fractional inhibitory concentrations of each compound were determined for planktonic cells. Next, 24-h single biofilms of C. albicans and S. mutans were treated for 24 h with the nanocompounds alone or in combination with TYR, and the antibiofilm effect was assessed through enumeration of colony forming units. Biofilm data were statistically examined using one-way ANOVA and the Kruskal-Wallis test (α = 0.05). The chemically synthesized nanocompound in combination with TYR demonstrated a synergistic effect against planktonic cells of C. albicans and S. mutans. For the nanocompound obtained through the 'green' route associated with TYR, a synergistic effect was observed only against C. albicans. For biofilms, only the combination obtained through the 'green' route + TYR demonstrated a synergistic effect against C. albicans. Our results may contribute to the development of oral care products containing AgNPs-CaGP and TYR to combat oral infections.

'Green' silver nanoparticles combined with tyrosol as potential oral antimicrobial therapy.

OBJECTIVES: This study aimed to evaluate silver nanoparticles (AgNPs) obtained by a 'green' route associated or not to tyrosol (TYR) against Streptococcus mutans and Candida albicans in planktonic and biofilms states. METHODS: AgNPs were obtained by a 'green' route using pomegranate extract. The minimum inhibitory concentration (MIC) against S. mutans and C. albicans was determined for AgNPs and TYR combined and alone, and fractional inhibitory concentration index (FICI) was calculated. Single biofilms of C. albicans and S. mutans were cultivated for 24 h and then treated with drugs alone or in combination for 24 h. RESULTS: AgNPs and TYR were effective against C. albicans and S. mutans considering planktonic cells alone and combined. The MIC values obtained for C. albicans was 312.5 µg/mL (AgNPs) and 50 mM (TYR) and for S. mutans was 78.1 µg/mL (AgNPs) and 90 mM (TYR). The combination of these antimicrobial agents was also effective against both microorganisms: 2.44 µg/mL/0.08 mM (AgNPs/TYR) for C. albicans and 39.05 µg/mL /1.25 mM (AgNPs/TYR) for S. mutans. However, synergism was observed only for C. albicans (FICI 0.008). When biofilm was evaluated, a reduction of 4.62 log10 was observed for S. mutans biofilm cells treated with AgNPs (p < 0.05, Tukey test). However, the addition of TYR to AgNPs did not improve their action against biofilm cells (p > 0.05). AgNPs combined with TYR demonstrated a synergistic effect against C. albicans biofilms. CONCLUSIONS: These findings suggest the potential use of AgNPs with or without TYR against C. albicans and S. mutans, important oral pathogens. CLINICAL SIGNIFICANCE: AgNPs obtained by a 'green' route combined or not with TYR can be an alternative to develop several types of oral antimicrobial therapies and biomaterials.

Anti-biofilm activity of silver nanoparticles against different microorganisms.

Biofilms confer protection from adverse environmental conditions and can be reservoirs for pathogenic organisms and sources of disease outbreaks, especially in medical devices. The goal of this research was to evaluate the anti-biofilm activities of silver nanoparticles (AgNPs) against several microorganisms of clinical interest. The antimicrobial activity of AgNPs was tested within biofilms generated under static conditions and also under high fluid shears conditions using a bioreactor. A 4-log reduction in the number of colony-forming units of Pseudomonas aeruginosa was recorded under turbulent fluid conditions in the CDC reactor on exposure to 100 mg ml(-1) of AgNPs. The antibacterial activity of AgNPs on various microbial strains grown on polycarbonate membranes is reported. In conclusion, AgNPs effectively prevent the formation of biofilms and kill bacteria in established biofilms, which suggests that AgNPs could be used for prevention and treatment of biofilm-related infections. Further research and development are necessary to translate this technology into therapeutic and preventive strategies.

The importance of a multifaceted approach to characterizing the microbial flora of chronic wounds.

Chronic wounds contain complex polymicrobial communities of sessile organisms that have been underappreciated because of limitations of standard culture techniques. The aim of this work was to combine recently developed next-generation investigative techniques to comprehensively describe the microbial characteristics of chronic wounds. Tissue samples were obtained from 15 patients with chronic wounds presenting to the Johns Hopkins Wound Center. Standard bacteriological cultures demonstrated an average of three common bacterial species in wound samples. By contrast, high-throughput pyrosequencing revealed increased bacterial diversity with an average of 17 genera in each wound. Data from microbial community profiling of chronic wounds were compared with published sequenced analyses of bacteria from normal skin. Increased proportions of anaerobes, Gram-negative rods and Gram-positive cocci were found in chronic wounds. In addition, chronic wounds had significantly lower populations of Propionibacterium compared with normal skin. Using epifluorescence microscopy, wound bacteria were visualized in highly organized thick confluent biofilms or as scattered individual bacterial cells. Fluorescent in situ hybridization allowed for the visualization of Staphylococcus aureus cells in a wound sample. Quorum-sensing molecules were measured by bioassay to evaluate signaling patterns among bacteria in the wounds. A range of autoinducer-2 activities was detected in the wound samples. Collectively, these data provide new insights into the identity, organization, and behavior of bacteria in chronic wounds. Such information may provide important clues to effective future strategies in wound healing.

Green synthesis of silver nanoparticles combined to calcium glycerophosphate: antimicrobial and antibiofilm activities.

AIM: To synthesize, characterize and evaluate the antimicrobial and antibiofilm activities of novel nanocomposites containing silver nanoparticles (AgNPs) associated or not to ß-calcium glycerophosphate. MATERIALS & METHODS: These nanocomposites were produced through a 'green' route using extracts of different parts of pomegranate. Antimicrobial and antibiofilm properties against Candida albicans and Streptococcus mutans were determined by the minimum bactericidal/fungicidal concentration and biofilm density after treatments. RESULTS: All extracts used were successful in producing AgNPs. Composites made with peel extracts showed the highest antimicrobial and antibiofilm activity against both microorganisms tested and performed similarly or even better than chlorhexidine. CONCLUSION: AgNPs associated or not to calcium glycerophosphate produced by a 'green' process may be a promising novel antimicrobial agent against oral microorganisms.

Cross-contamination in the dental laboratory through the polishing procedure of complete dentures.

Polishing of dental prostheses can cause a dangerous cycle of cross-contamination involving dentists, laboratory technicians, patients and auxiliary personnel. The aim of this study was to show the microbial contamination in the dental laboratory during the polishing procedure of complete dentures. For this purpose, 4 experiments were conducted. Experiment I -- Determination of the total colony-forming units (CFU) counts contaminating complete maxillary dentures. During the polishing procedure, determination of the CFU counts transferred to the operator (Experiment II) and of the total CFU counts transferred to previously sterilized complete dentures (Experiment III). Experiment IV -- The total counts of remaining CFU in the lathe spindle after Experiments II and III. Complete dentures were highly contaminated (mean = 1.4 x 10(7) CFU/mL). There was a elevated level of contamination by splatter and aerosols. There was high microbial transfer from the contaminated lathe spindle to the sterile prostheses (mean = 1.7 x 10(7) CFU/mL). The spindles were highly contaminated after polishing procedures (mean = 3.5 x 10(8) CFU/mL). The polishing of dental prostheses is a possible source of transmission of communicable diseases in the laboratory and requires improved techniques for infection control.

Inhibition of Staphylococcus aureus biofilms by a novel antibacterial envelope for use with implantable cardiac devices.

Biofilm formation on representative implantable medical devices using a known human pathogen (Staphylococcus aureus) was significantly reduced (p < 0.01) at all time points measured (24,48, and 72 hours) by employing a novel antibacterial envelope (AIGIS Rx). The result was demonstrated using a standard US Centers for Disease Control (CDC) bioreactor model and the results were confirmed by Scanning Electron Microscopy (SEM). The antibacterial envelope used in the study is coated with a proprietary combination broad spectrum antibiotics (rifampin and minocycline) embedded in a resorbable polymeric coating. The antibiotics are designed to elute out of the coating over a multi-day period for controlled, site-specific drug delivery. The infection rate for patients receiving pacemakers and defibrillators is increasing faster than the rate of new implants and the growing resistance of S. aureus strains suggests that conventional, systemic antibiotic prophylaxis may have limited future utility. Moreover, emerging evidence suggests that bacterial biofilms result in infections of implantable medical devices. These findings demonstrate the in vitro efficacy of a new means to address potential biofilm-derived Hospital Acquired Infections (HAIs) related to implantable medical devices composed of titanium inclusive of pacemakers and defibrillators by means of a locally delivered, low dose, combination antibacterial treatment.

Diferentes métodos de avaliação do nível de contaminação microbiana da água de alta rotação / Diferent methodos of evaluation of microbiak contamination level of high-speed

A água do equipo odontológico que resfria os equipamentos giratórios/rotatórios de alta velocidade, como os de alta rotação, pode apresentar número elevado de microrganismos. Assim, os aerossóis formados são fonte de risco de disseminação/contaminação na odontologia. O objetivo desta pesquisa foi avaliar e comparar o nível de bactérias aeróbias mesófilas totais presentes em amostras de água de alta rotação (AR), de 10 equipos odontológicos da Faculdade de Odontologia de Ribeirão Preto - USP, por meio do método tradicional/convencional pour plate e o método rápido Petrifilm AC (3M, St Paul, MN, USA). Cerca de 10,0ml das amostras de água foram coletadas dos AR sem as peças de mão, em tubos de ensaio (25x125mm). As amostras foram homogeneizadas, diluídas, semeadas e incubadas. Todas as amostras de água dos AR estavam altamente contaminadas, não havendo diferença estatisticamente significante (p>0,05) entre o nível de contaminação encontrado pelo método tradicional, comparado com o método rápido. Em conclusão, o método rápido Petrifilm foi considerado mais prático que o tradicional, e totalmente adequado para monitorar a contaminação microbiana das águas dos AR que estavam acima do recomendado pela American Dental Association(<200UFC/ml) e do permitido pela legislação brasileira (<500UFC/ml). Então, para a melhoria da qualidade microbiológica da água de equipos odontológicos, as sugestões dos autores desse trabalho deveriam ser acatadas pelos profissionais da odontologia

Dental units have cold water that supplies gyration/rotation equipments of high-speed, such as highspeedhandpieces, may have a high number of microorganisms. Therefore, aerosol formation is a risksource of microbial dissemination/contamination in dentistry. The aim of this research was to evaluateand compare total aerobic bacteria contamination level in high-speed (HS) water from 10 dental units atFaculty of Dentistry of Ribeirão Preto - USP using a traditional method, pour plate and a fast method, PetrifilmTM AC (3M, St Paul, MN, USA). Approximately 10.0ml of dental unit water were collected from HS, without handpieces, in tubes (25x125mm). The samples were homogenized, diluted, inoculated and incubated. All HS water samples were highly contaminated, no having statistical difference (p>0.05)between contamination level got traditional and fast method. In conclusion, the fast method PetrifilmTM was considered more useful than traditional method, and totally acceptable to monitor the microbial contamination in water from HS that was higher than American Dental Association's recommendation (<200CFU/ml) and allowed for Brazilian legislation (<500CFU/ml). Thus, to improve the water microbiology quality from dental units, the authors´ suggestions this work should be followed by dental professionals

Aspectos sócio-econômicos dos pacientes atendidos nas clínicas da Faculdade de Odontologia de Ribeiräo Preto - USP / Socio-economic conditions of patients seen at the clinics of the Ribeiräo Preto school of dentistry, University of Säo Paulo, Brazil

O objetivo deste estudo foi conhecer as condiçöes sócio-econômicas dos pacientes atendidos nas clínicas da Faculdade de Odontologia de Ribeiräo Preto-USP no segundo semestre de 1994. Para tanto, foi aplicado um questionário, obtendo-se 532 (76 por cento) respostas. os resultados mostraram que, em média, moravam 4 pessoas por casa, dentre as quais 1,8 trabalhavam. Além disso, 55,7 por cento das famílias dos pacientes possuíam renda mensal inferior a 5 salários mínimos; 66,5 por cento possuíam casa própria e 50,2 por cento dos pacientes näo concluíram o primeiro grau. Concluiu-se, entäo, que os pacientes que participaram do estudo possuíam, em sua maioria, baixa renda familiar mensal e baixo nível de escolaridade

Cross-contamination in the dental laboratory through the polishing procedure of complete dentures

O polimento de próteses dentais pode causar um ciclo de contaminação cruzada envolvendo cirurgões-dentistas, técnicos de laboratório, pacientes e pessoal auxiliar. O objetivo deste estudo foi demonstrar a contaminação microbiana em laboratório dental durante os procedimentos de polimento de próteses totais. Com esse propósito, 4 experimentos foram idealizados: Experimento I - Determinação da contagem total de unidades formadoras de colônias (UFC) presentes em próteses totais superiores. Durante o procedimento de polimento, determinação da contagem de UFC transferidas para o operador (Experimento II) e contagem total transferida para próteses totais previamente esterilizadas (Experimento III). Experimento IV - Contagem total de UFC remanescentes no cone da politriz após a realização dos experimentos II e III. As próteses totais estavam altamente contaminadas (média = 1,4 x 107 UFC/mL). Observou-se um elevado nível de contaminação pelo aerosol. Houve transferência de microrganismos da politriz contaminada para as próteses esterilizadas (média = 1,7 x 107 UFC/mL). Os cones estavam altamente contaminados depois dos procedimentos de polimento (média = 3,5 x 108 UFC/mL). O polimento de próteses dentais é um possível veículo de transmissão de doenças no ambiente do laboratório e requer técnicas adequadas para o controle de infecção.

Núcleos metálicos fundidos x pinos pré-fabricados / Cast metal posts x pre-fabricated posts

A restauração de um dente tratado endodonticamente, com ampla destruição coronária, tem se constituído em um desafio para clínicos e pesquisadores. Os núcleos metálicos fundidos são, há mais de cem anos, a solução mais empregada para recuperação destes dentes. Com o surgimento dos núcleos pré-fabricados, que tem baixo custo, facilidade de técnica e são mais estéticos, os núcleos metálicos fundidos estão sendo menos utiizados. O objetivo deste trabalho foi revisar a literatura a respeito dos vários tipos de pinos pré-fabricados, comparando-os com os tradicionais núcleos metálicos fundidos. Concluiu-se que ainda não existe um pino pré-fabricado com material e técnica que supra todos os casos e substitua em definitivo os núcleos metálicos fundidos

Prótese total com dentes desgastados x disfunção temporomandibular: relato de caso / Complete dentures with worn teeth x temporomandibular dysfunction: a case report

A presença de disfunção temporomandibular em portadores de prótese total tem sido descrita com freqüência. Sua etiologia multifatorial envolve fatores emocionais e alterações no sistema estomatognático em função da prótese. Hábitos parafuncionais, assim como o desgaste de dentes e relações maxilo-mandibulares incorretas têm sido considerados fatores importantes e que precisam receber especial atenção pelo profissional. A solução destas alterações pode ser obtida por meio de aparelhos removíveis ou adição de resina à prótese existente, mas como no caso clínico descrito, antes da confecção de novas próteses, é fundamental que o restabelecimento da dimensão vertical de oclusão seja feita de forma criteriosa e que o paciente seja observado por um período de tempo para a certificação de sua adaptação à nova dimensão.

Conexão dente-implante: relato de caso clínico / Connection tooth-implant: a case report

Inicialmente, a indicação dos implantes estava restrita apenas à região anterior da mandíbula. Porém, quando o sucesso dos implantes osseointegrados tornou-se evidente, sua utilização expandiu-se para as regiões anteriores e posteriores de ambas as arcadas, em pacientes total ou parcialmente desdentados. Levantaram-se, então, dúvidas se os dentes naturais poderiam ou não ser conectados aos implantes. Entretanto, em várias situações, a união entre dentes e implantes torna-se necessária e pode ser realizada, desde que com conhecimento e respeito a critérios previamente estabelecidos para o planejamento, a execução e proservação. Com base nesses critérios, é apresentado um caso clínico em que a união entre dentes naturais e implantes mostrou ser um tratamento viável

Fatores que influem na espessura da película de cimentaçäo / Factors affecting cement film thickness

A espessura da película do agente cimentante pode determinar o assentamento incompleto de coroas na fase de cimentaçäo. Assim, os autores fazem uma revisäo dos fatores que afetam a espessura do filme de cimento e apresentam meios de manter essa espessura em níveis aceitáveis, garantindo o resultado final satisfatório da restauraçäo

Avaliaçäo da distância intercondilar em pacientes jovens / Evaluation of the intercondylar distance in young patients

O objetivo deste trabalho foi verificar se a distância intercondilar (DI) de uma amostra de 80 pacientes, com idades entre 19 e 26 anos, estava de acordo com a afirmaçäo de DAWSON (1993) de que poucos pacientes têm DI variando mais que 10 mm em relaçäo à média de 110 mm, e discutir a individualizaçäo da DI no articulador. As medidas realizadas com arco facial (modelo 8600A, Gnatus, Ribeiräo Preto, Brasil) revelaram uma média de 118,16 mm de DI, estatisticamente diferente da medida dada por DAWSON (1993), a nível de 1 por cento. A distância intercondilar é um dos determinantes da morfologia oclusal dos dentes e, portanto, sua transferência, para o articulador, para a confecçäo de restauraçöes protéticas é recomendada na literatura mundial. Entretanto, uma padronizaçäo dos arcos faciais auriculares é necessária