Atividade antimicrobiana e antiaderente in vitro do extrato de rosmarinus officinalis linn. (alecrim) sobre microrganismos cariogênicos / Antimicrobial and antiadherent activity, in vitro, of rosmarinus officinalis linn. (alecrim) extract tested on cariogenic microrganisms

A atividade antimicrobiana e antiaderente in vitro do extrato do alecrim (Rosmarinus officinalis Linn.) foram avaliadas sobre Streptococcus mitis, S. mutans, S. sanguis, S. sobrinus e L. casei. O estudo foi realizado utilizando-se técnicas bacteriológicas. Os ensaios foram realizados pelas técnicas de ágar difusão em placas para determinação da Concentração Inibitória Mínima (CIM) e técnica dos tubos inclinados para a Concentração Inibitória Mínima de Aderência (CIMA). Os resultados mostraram a potencialidade daRosmarinus officinalis Linn. na inibição do crescimento bacteriano e síntese de glucano, sugerindo a sua utilização, como meio alternativo, no controle de bactérias cariogênicas.

Fluoride ingestion from toothpaste: background to European Union-funded multicentre project.

As in most other established market economies throughout the world the prevalence of dental caries has declined in most Member States of the European Union (EU). There is evidence that the increased use of fluoride toothpaste has been a major factor in this improvement. Recently there has been increasing debate on the alleged link between increased use of fluoride toothpaste, particularly by infants and young children, and increased levels of enamel fluorosis. Central to these discussions are two issues, namely measurement of the amount of fluoride ingested by infants and young children and measurement of enamel opacities including fluorosis. The aims of the project described in this special issue addressed these two measurement issues. Seven EU Partners participated. Standardized methods for recording the amount of fluoride ingested when using fluoride toothpaste were developed and used in the seven sites. Similarly a standardized photographic method for recording enamel opacities, including fluorosis, was developed.

Construction and evaluation of an inexpensive device that simulates oral clearance / monstrução e avaliação de um dispositivo de baixo custo simulador do clearace oral

O perfil do clearance de uma determinada substância é muito importante para se estimar a sua disponibilidade oral. Dispositivos ou modelos que simulam o clearance na cavidade oral são importantes para se estudar os efeitos e tempos de retenção de alimentos e fármacos. Este trabalho descreve um eficiente dispositivo, desenvolvido em nosso laboratório com materiais de baixo custo, que pode ser utilizado para o estudo do clearance de substratos cariogênicos, enxagatórios bucais e fármacos de liberação programada, bem como, avaliar a adsorção de fármacos ao esmalte. O dispositivo apresenta três câmaras com volumes mínimo e máximo variáveis, que podem ser eluidas, simultaneamente, em diferentes fluxos. Os volumes de deglutição simulados são ajustáveis e a razão entre os volumes mínimo e máximo pode ser programada. Também são apresentados os resultados de um estudo de avaliação do dispositivo onde determinou-se o clearance de fluoreto proveniente de um enxaguatório bucal, o clearance de uma solução de glicose a 1 por cento e a liberação programada de fluoreto a partir de um adesivo de metacrilato, usando saliva artificial como eluente

Construction and evaluation of an inexpensive device that simulates oral clearance.

The clearance pattern of a specific substance is very important to estimate its oral availability. Devices or models that simulate clearance in the mouth are important to study the effects and retention time of foods and drugs. This report describes an efficient device which was assembled with low-cost materials in our laboratory and that can be used to study the clearance of cariogenic substrates, mouthwashes, programmed-release drugs as well as adsorption of drugs to enamel. The device can have up to three chambers with varying minimum and maximum volumes that can be eluted simultaneously at different flows. The simulated swallowed volumes are adjustable and the ratio between the maximum and minimum volumes can be programmed. We also present the results of an evaluation study using the device to determine the clearance of fluoride from a fluoride-containing mouthwash, the clearance of a 1% glucose solution and the programmed release of fluoride from a methacrylate bioadhesive using artificial saliva as eluent.

Análise in vitro da concentração de sacarose e pH de antibacterianos de uso pediátrico / In vitro analysis of sucrose concentration and pH of pediatric antibiotics

O objetivo deste trabalho foi determinar a Concentração de Sacarose (CS) e o pH de dez antibacterianos (Ab) de uso pediátrico disponíveis no mercado brasileiro.Foram analisados duas amostras de cada uma das dez marcas comerciais de Ab utilizadas no presente estudo.A análise da CS foi realizada no Laboratório de Bioquímica Nutricional e de Alimentos da UFRJ, através da Cromatografia Líquida de Alta Eficiência, utilizando-se uma bomba HPLC (Isco-USA) com uma válvula de injeção Rheodyne (com alça de 20 ml), um detector de índice de refração (Waters 410-USA) e uma coluna Lichrospher-5-NH2 (250x4 mm i.d.-Merck-Germany), onde a fase móvel utilizada constitui-se de acetonitrila: água (72:28, v/v) a 1,0 ml/mm. Dois gramas de cada solução antibacteriana foram diluídos em água destilada (1:50) até completar 100 ml de solução. Em seguida, a solução foi diluída em acetonitrila (1;1). Após centrifugação, o sobrenadante foi analisado no cromatógrafo. A quantificação da concentração de sacarose dos antibacterianos foi obtida através da comparação das alturas dos picos de sacarose destes medicamentos com as alturas dos picos de sacarose de soluções-padrão (Merck). O pH dos antibacterianos foi determinado utilizando-se um pHmetro Digimed DM 20 do laboratório de Saúde Bucal do Curso de de Pós-graduação em Odontologia Social da UFF. Calculou-se a média aritmética das duas amostras de cada uma das dez marcas comerciais de Ab utilizadas no presente estudo. A análise dos resultados foi feita através da determinação da mediana dos valores médios encontrados. Como resultados pôde-se verificar uma mediana da concentração média de sacarose de 29.,80 por cento (0, por cento - 41,30 por cento). Da mesma maneira a mediana para os valores de pH foi de 5,46 (5,09 - 8,27). Conclui-se, a partir deste estudo piloto, que existe uma alta concentração de sacarose e um pH abaixo do crítico na maioria dos antibacterianos avaliados, o que pode estar contribuindo para o aumento do potencial cariogênico e erosivo destes medicamentos de uso pediátrico

In situ acid resistance of in vivo formed white spot lesions.

Thin sections of natural enamel lesions, so-called white spots (WS), and areas of sound enamel (SEn) adjacent to the WS were exposed to an intraoral environment for 2 weeks. Thin sections of WS samples, clamped in a PMMA holder, were microradiographed before and after exposure to intraoral conditions. Acid resistance was evaluated by lesion depth and mineral changes during the cariogenic challenge. The results show that there were statistically significant differences in lesion depth, mineral loss and mineral volume percent at the surface before and after the intraoral cariogenic challenge at least at p<0.05, except for a change in mineral volume percent at the surface of WS samples. This exception indicates that no mineral change occurred in the surface layer of WS. The fact of 2.8 and 1.8 times higher ratios of SEn over WS of mean changes in lesion depth and mineral loss data, respectively, seems to indicate a quantitative difference in acid resistance level of WS lesions compared with the areas of SEn. Regarding the site of mineral changes, a distinctive feature of WS samples is that mineral loss occurs at the bottom of lesions. In contrast, areas of SEn produce a typical subsurface type of lesions. From this in situ study, it can be concluded that the surface of WS samples was apparently much more acid-resistant (at least approximately 2 times) than the areas of SEn that received a similar intraoral acid challenge.

Computer modeling of the effects of chewing sugar-free and sucrose-containing gums on the pH changes in dental plaque associated with a cariogenic challenge at different intra-oral sites.

Variation in salivary access to different intra-oral sites is an important factor in the site-dependence of dental caries. This study explored, theoretically, how access is modified by chewing sugar-free and sugar-containing gums. A finite difference computer model, described elsewhere, was used. This allowed for diffusion and/or reaction of substrate, acid product, salivary buffers, and fixed-acid groups. Site-dependent saliva/plaque exchange was modeled in terms of a 100-microns-thick salivary film covering the plaque (a) flowing directly from the salivary ducts, (b) flowing from the intra-oral salivary pool, or (c) exchanging with the pool. Computed flow-velocities or rates of exchange were based on previous intra-oral measurements. The model was also tested against an in vitro study conducted by two of the authors. In addition, the three proposed models of saliva/plaque interaction were compared, and the effect of salivary film thickness investigate. Results suggested that: (1) although sugar-free gum chewed during a cariogenic challenge causes a rapid rise in plaque pH, sucrose-containing gums cause the pH, after a temporary rise resulting from increased salivary flow, to stay low for an extended period; (2) the computer model reproduced in vitro tests reasonably well; (3) although the three models of the plaque/saliva interaction start from different assumptions, two lead to closely related predictions; and (4) increasing the assumed salivary film thickness by a large amount (e.g., from 50 to 200 microns) caused no change in modeled Stephan curves, as long as these changes were accompanied by appropriate reductions in film velocity, in accord, theoretically, with the practical clearance data.

Benign myocardial uptake of hydroxymethylene diphosphonate.

During 'routine' bone scanning with diphosphonates, 10 elderly men were noted to show prominent myocardial uptake of Tc-hydroxymethylene diphosphonate (HDP) consistently, but no heart activity was seen with Tc-methylene disphosphonate (MDP). None had evidence of recent myocardial injury and the uptake persisted over a period of many months. In some, myocardial uptake defects were noted, analogous to 201Tl- and Tc-methoxyisobutyl isonitrile (MIBI) scans postinfarction. The condition appears to be essentially benign but its aetiology remains obscure. We have not been able to identify its cause; presumably atherosclerosis is one factor.