Mechanical, chemical and antimicrobial properties of a bisphenol A-free pit-and-fissure sealant.

PURPOSE: To evaluate, in vitro, mechanical, chemical and antimicrobial properties of Embrace Wetbond bisphenol A (BPA)-free pit-and-fissure sealant. METHODS: For the shear bond strength and microleakage tests, 135 healthy third molars were randomly divided into six groups, according to sealant [Fluroshield (FS) and Embrace Wetbond (EWB)] and contamination conditions (no contamination, contamination with saliva and contamination with water). In addition, EWB sealant was subjected to the following analyses: fluoride release using direct potentiometry, antimicrobial activity using the agar well diffusion method and quantification of BPA using gas chromatography and mass spectrometry. Data were analyzed statistically by ANOVA, Kruskal-Wallis test, Tukey's post-test, Dunn's post-test and Bonferroni post-test (α= 0.05). RESULTS: For shear bond strength, there was a statistically significant difference among the groups (P< 0.05), and FS presented the best results. Analysis of the microleakage results showed statistically significant differences among the groups (P< 0.05), except for EWB non-contaminated, contaminated with saliva, and contaminated with water (P> 0.05). FS without contamination presented the lowest microleakage of all groups (P< 0.05), followed by FS contaminated with saliva, and three groups in which EWB was used under different conditions. FS contaminated with water presented the highest microleakage (P< 0.05). EWB showed higher fluoride release in water and artificial saliva on the first day (P< 0.05). EWB had greater antimicrobial activity than FS. BPA and Bis-GMA were not detected in EWB. When used according to the manufacturer's instructions (i.e., under conditions of moisture contamination), EWB showed high fluoride release, high antimicrobial activity, no release of BPA or Bis-GMA and shear bond strength close to the minimum acceptable value. However, this sealant presented statistically significantly more microleakage than the other tested materials. CLINICAL SIGNIFICANCE: Knowing the adverse effects of BPA in the body, the present study has clinical relevance since it demonstrates some mechanical, chemical and antimicrobial properties of a BPA-free pit-and-fissure sealant.

Liquid crystalline phase nanodispersions enable skin delivery of siRNA.

The ability of small interfering RNAs (siRNAs) to potently but reversibly silence genes in vivo has made them particularly well suited as a new class of drugs that interfere with disease-causing or disease-promoting genes. However, the largest remaining hurdle for the widespread use of this technology in skin is the lack of an effective delivery system. The aim of the present study was to evaluate nanodispersed systems in liquid crystalline phases that deliver siRNA into the skin. The proposed systems present important properties for the delivery of macromolecules in a biological medium, as they are formed by substances that have absorption-enhancing and fusogenic effects; additionally, they facilitate entrapment by cellular membranes due to their nano-scale structure. The cationic polymer polyethylenimine (PEI) or the cationic lipid oleylamine (OAM) were added to monoolein (MO)-based systems in different concentrations, and after dispersion in aqueous medium, liquid crystalline phase nanodispersions were obtained and characterized by their physicochemical properties. Then, in vitro penetration studies using diffusion cell and pig ear skin were carried out to evaluate the effect of the nanodispersions on the skin penetration of siRNA; based on these results, the nanodispersions containing MO/OA/PEI/aqueous phase (8:2:5:85, w/w/w/w) and MO/OA/OAM/aqueous phase (8:2:2:88, w/w/w/w) were selected. These systems were investigated in vivo for skin penetration, skin irritation, and the ability to knockdown glyceraldehyde 3-phosphate dehydrogenase (GAPDH) protein levels in animal models. The results showed that the studied nanodispersions may represent a promising new non-viral vehicle and can be considered highly advantageous in the treatment of skin disorders; they were effective in optimizing the skin penetration of siRNA and reducing the levels of the model protein GAPDH without causing skin irritation.

Monoolein and chitosan gels as potential carriers of the rhBMP-2, using decortication surgical technique in Wistar rats as experimental model.

The purpose of this work was to evaluate the new bone tissue, comparing two different carriers for rhBMP-2, monoolein and chitosan gels, using the decortication and nondecorticatication surgical technique in rat mandibles, evaluated by histomorphometrical method. It was used 56 male Wistar rats (300 g), divided into 8 groups according to the rhBMP-2 carrier used, monoolein or chitosan gels; surgical technique, bone decortication or nondecortication; and period of time, 3 or 6 weeks until the sacrifice by perfusion. Results obtained in this study showed that the rhBMP-2/monoolein and rhBMP-2/chitosan used in this experimental model was able to induce osteogenesis, contributing to the bone healing process. The bone repair process was time dependent, so that at 6 weeks there was an improved amount of new bone in relation to 3 weeks, considered each analyzed group, and the decortication was able to expose the bone marrow and speed up the bone healing process, which was showed by histomorphometrical methods. Both of carriers were capable to adapt to the bone surgical area, according to the clinical observations, and had favorable properties in relation to protein releasing, revealed by the amount of new bone tissue found in the histological analysis.

Development of a colorimetric system for evaluation of the masticatory efficiency.

The stomatognathic system is responsible for complex vital functions such as chewing, deglutition, respiration and phonation. Food breakdown is one of the masticatory functions, which enables reducing the attrition against the oral soft tissues and increasing the surface contact of food particles with digestive secretions, thus leading to satisfactory and rapid physiological processes. The methods of evaluation the masticatory efficiency are restricted to electromyography, sieving and clinical observation. However, the validity of these methods has been questioned due to the complexity of the procedures, variances in the material used and inaccuracy of methodologies. This study presents a new method in which a capsule of a synthetic material using fuchsin-containing granules was devised. Such capsules were submitted to several laboratory tests in order to determine their resistance and absorbency. Ten calibrated individuals were instructed to chew the capsules. Masticatory efficiency was determined by analyzing fuchsin concentration in a solution obtained from chewed granules measuring the absorbance at 546 nm. The method was found to be fast, simple, reproducible, inexpensive and efficient and can be used as a complementary evaluation of the masticatory efficiency in different situations.

Development of a colorimetric system for evaluation of the masticatory efficiency

O sistema estomatognático é responsável por funções complexas vitais para o organismo como a mastigação, deglutição, respiração e fonação. A função mastigatória destina-se a dividir os alimentos, diminuindo o atrito contra os tecidos moles da boca e aumentando a superfície de contato entre os alimentos e as secreções digestivas, possibilitando um processo fisiológico adequado e rápido. As possibilidades de avaliação desta função está restrita ao uso das eletromiografias, das tamises e da observação clínica. No entanto, há divergências quanto à validade destes métodos devido à complexidade dos procedimentos, variações dos materiais-teste utilizados e à imprecisão das metodologias empregadas. Este trabalho apresenta uma cápsula de material sintético dentro da qual estão contidos grânulos que apresentam fucsina básica em sua composição. Essas cápsulas passaram por vários testes laboratoriais para determinação de sua resistência e de sua absorbância. Dez indivíduos foram instruídos a mastigar estas cápsulas. A eficiência mastigatória foi determinada através da concentração da pigmentação de fucsina numa solução obtida dos grânulos mastigados por meio da medida da absorbância em 546 nm. Foi demonstrado que o método é rápido, simples, reprodutível, de baixo custo e eficaz e pode ser usado como método complementar para a avaliação da eficiência mastigatória em diferentes situações.

Dissociação iônica de medicações intracanais experimentais à base de hidróxido de cálcio / Ionic dissociation of experimental calcium hydroxide based intracanal medicaments

Na Endodontia, quando o tratamento endodôntico, por alguma razão, não pode ser concluído na mesma sessão é identificado o uso de um medicamento no interior do canal radicular, temporário, chamado medicação intracanal. Atualmente, os compostos a base de hidróxido de calcio mostram propriedades desejáveis para esta finalidade, entretanto, sua ação depende de sua capacidade em dissociar-se em íons e hidroxila. Assim, o presente trabalho analisou as concentrações de íons cálcio e o pH proporcionado por quatro diferentes substâncias experimentais propostas como medicamento intracanal. Para tal, foram utilizados 100 dentes incisivos inferiores humanos, formando quatro grupos experimentais: hidróxido de cálcio PA e água destilida, hidróxido de cálcio adicionado ao Aderogil, hidróxido de cálcio adicionado ao Adeforte e a pasta base do cimento Life. A concentração de íons cálcio e o pH foram avaliados no instante inicial, 1,27,14,17 e 33 dias após a colocação dos espécimes em meio aquoso. Após a análise estatística, que evidenciou haver significância ao nível de 1%,organizou-se os materiais na seguinte ordem decrescente de liberação de...

Comparative evaluation of in-vitro effects of Brazilian green propolis and Baccharis dracunculifolia extracts on cariogenic factors of Streptococcus mutans.

Streptococcus mutans triggers dental caries establishment by two major factors: synthesis of organic acids, which demineralize dental enamel, and synthesis of glucans, which mediate the attachment of bacteria to the tooth surface. Propolis is a natural product that may prevent dental caries. Baccharis dracunculifolia DC (Asteraceae), a native plant from Brazil, is the most important botanical origin for the production of green propolis (Brazilian propolis) by honeybees. However, whether B. dracunculifolia (Bd) has an anticariogenic effect, like green propolis, remains unknown. Herein, we have made a comparative evaluation of the effects of extracts from green propolis and Bd on the glucan synthesis and acidogenic potential of S. mutans. The inhibitory effects of the extracts on bacterial acid production were evaluated through the potentiometric measurement of pH from bacterial suspensions treated with serial concentrations of both extracts. Besides presenting close inhibitory values at the same concentration range, Bd leaf rinse and green propolis extracts had similar IC(50) values (0.41 and 0.34 mg/ml, respectively). Both extracts produced a bacteriostatic effect on S. mutans cultures at a concentration of 0.40 mg/ml. Estimated inhibitory values of green propolis and Bd leaf rinse extracts on the synthesis of insoluble glucans (IC(50)=12.9 and 25.0 microg/ml, respectively) and soluble glucans (IC(50)=50.4 and 49.1 microg/ml, respectively) were not significantly different from each other at p<0.05. The results demonstrate that Bd leaf rinse and green propolis extracts have similar inhibitory effects on the S. mutans cariogenic factors evaluated herein, and allowed us to suggest that Bd leaves may be a potential source for pharmaceutical products employed for this purpose.

Clinical and biochemical evaluation of the saliva of patients with xerostomia induced by radiotherapy.

Clinical aspects and biochemical properties in the saliva of 21 patients prior to and following radiotherapy for head and neck cancer were evaluated (experimental group) and compared with the same properties in a control group of 21 subjects free of cancer. Salivary flow was evaluated by measuring the time necessary, in seconds, for the output of 2 ml of stimulated saliva; and the buffering capacity changes were determined using a simple colorimetric method. Total salivary protein concentration was determined by the Bradford 4 method. Amylase activity was measured by reducing sugars released from a soluble starch substrate, quantified by the dinitrosalicylic method. The electrophoretic profile was evaluated in polyacrylamide gel (12% SDS-PAGE) using samples of 5 mg of salivary protein. A statistically significant reduction (p < 0.01) of the salivary flow was observed, (162.47 s +/- 28.30 before and 568.71 s +/- 79.75 after irradiation), as well as a reduction in the salivary buffering capacity (pH 5.45 +/- 0.14 before and pH 4.40 +/- 0.15 after irradiation). No statistically significant alteration was observed in total salivary protein concentration. A statistically significant reduction (p < 0.01) of salivary alpha-amylase activity (856.6 ng/mg +/- 88.0 before and 567.0 ng/mg +/- 120.6 after irradiation) was observed. Electrophoretic profile differences in salivary protein bands were also observed after radiotherapy, mainly in the range of molecular weight of 72000 to 55000 Daltons. Clinically, patients presenting xerostomia induced by radiotherapy presented an increase in oral tissue injury.

Clinical and biochemical evaluation of the saliva of patients with xerostomia induced by radiotherapy

Foram avaliados alguns aspectos clínicos e algumas propriedades bioquímicas salivares de 21 pacientes, antes e após o tratamento radioterápico para câncer de cabeça e pescoço (grupo experimental) e de 21 pacientes sem câncer (grupo controle). O fluxo salivar foi avaliado pelo tempo necessário (segundos) para produção estimulada de 2 ml de saliva e a capacidade tamponante determinada frente à utilização de um método colorimétrico simples. A concentração de proteína total salivar foi determinada pelo método de Bradford4. A atividade da amilase foi mensurada através dos açúcares redutores liberados e quantificados pelo método do ácido dinitrossalicílico utilizando a glicose como substrato. O perfil eletroforético foi avaliado em gel de poliacrilamida (SDS-PAGE 12%) para amostras salivares contendo 5 mg de proteína. Foi observada, no grupo experimental, redução estatisticamente significativa (p < 0,01) para o fluxo salivar (162,47 s ± 28,30 antes e 568,71 s ± 79,75 após) e para a capacidade tamponante (pH 5,45 ± 0,14 antes e 4,40 ± 0,15 após). Não foi observada alteração estatisticamente significativa na concentração de proteína. A atividade específica da a-amilase foi significativamente diminuída (p < 0,01) (856,6 ng/mg ± 88,0 antes e 567,0 ng/mg ± 120,6 após). No perfil eletroforético, foram observadas diferenças nas bandas protéicas, principalmente na faixa de peso molecular de 72.000 a 55.000 Da. Clinicamente, os pacientes com xerostomia induzida pela radioterapia apresentaram aumento de lesões na mucosa.

Evaluation of the influence of cetylamine fluoride and sodium fluoride on acid production by S. mutans

The acidogenic character of Streptococcus mutans has been pointed out as one of the most important physiological aspects associated with dental caries establishment. Fluoride is a key component of oral health promotion. Amine fluorides (AmF) have been used in products such as mouth rinses, toothpastes, gels and other topical fluoride agents for over 30 years in several European countries. In Brazil, the use of such substances was limited to toothpaste until August 2000, when a new resolution was published to approve the use of three AmFs in mouth rinses and other formulations for odontological purposes. In this report the influence of cetylamine fluoride (CAmF) and sodium fluoride (NaF) on acid production...

In vivo and in vitro studies of a cetylamine fluoride mouthrinse: evaluation of a decive used for in vitro experiments / Estudos in vivo e in vitro de enxaguatório bucal contendo cetilamino fluoreto: validaçäo de dispositivo usado nos experimentos in vitro

Um enxaguatório bucal contendo cetilamino fluoreto (230 ppm de fluoreto) foi preparado para estudos in vitro do clearance de fluoreto e adsorçäo deste íon pelo esmalte dental e/ou hidroxiapatita, utilizando um dispositivo que simula a cavidade oral. Os estudos in vivo do clearance de fluoreto a partir desse enxaguatório bucal foram realizados e comparados com outras fontes de fluoreto. A quantidade de fluoreto absorvida aos blocos de dente ou hidroxiapatita em pó, ambos tratados com o enxaguatório bucal de cetilamino fluoreto, uma ou duas vezes ao dia, foi determinada. Os resultados desses estudos demonstraram ser possível a preparaçäo de enxaguatório bucal contendo cetilamino fluoreto como alternativa para a prevençäo e terapêutica de cáries dentárias

Método para avaliaçäo clínica da capacidade tamponante salivar / A method for the clinical evaluation of salivary buffer capacity

O presente estudo teve por objetivo o desenvolvimento e a padronizaçäo de um método colorimétrico para avaliar a capacidade tamponante salivar média de nossa populaçäo. As amostras de saliva estimulada foram tituladas sem eliminaçäo do CO². Estudos foram realizados para verificar a influência da perda de CO² das amostras durante o período necessário para a realizaçäo das titulaçöes e para a padronizaçäo do tempo de leitura do pH. A partir das titulaçöes realizadas nas amostras de saliva de 206 indivíduos de ambos os sexos na faixa etária de 5 aos 50 anos, na proporçäo de 0,77 : 1 : 0,44, respectivamente para crianças, jovens e adultos, foram feitas as distribuiçöes de freqüências dos casos, a determinaçäo média do pH inicial, do pKa, microequivalentes relativos ao final da titulaçäo, pH final da titulaçäo e uma estimativa da porcentagem da saliva titulada em pH 5...

Enamel fluoride concentrations in unerupted third molars and the influence of fluoridated water on caries scores / Concentração do esmalte fluoretado em terceiros molares não erupcionados e a influência da água fluoretada em escores de cárie

Enamel fluoride concentrations in buccal and lingual surfaces were determined in successive layers obtained by the acid etch method. The 48 unerupted third molar teeth were from subjects who had lived continuosly since birth in two Brazilian towns (Barretos and Ribeirão Prêto) with different fluoride levels in the drinking water but with similar socioeconomic conditions. The DMFT index was determined for children 7-12 years old living in the two towns. Enamel fluoride concentrations were significantly higher in the teeth from the town with higher fluoride levels in drinking water. The children residing in the community with near-optimum fluoride concentration in the water had mean DMFT scores that were less than half those found in the community with a low level of fluoride in the drinking water

Verificação da efetividade de esterilização de um equipamento a vapor químico insaturado: estudo-piloto / Verification of the sterilization efectivity of an insatured chemical steam equipment: pilot-study

Este estudo-piloto trata do emprego de um equipamento a vapor químico insaturado para ser usado como método de esterilização. O aparelho é de origem nacional e a solução à base de álcoois. Os resultados iniciais são positivos

Avaliação do teor de fluoreto na água de abastecimento de cidades na região de Ribeirão Preto / Evaluation of community water supply in towns of Ribeirão Preto region

O teor de fluoreto na água de abastecimento de 68 cidades da região de Ribeirão Preto (SP) foi avaliada pelo método do eletrodo seletivo. As amostras foram recolhidas em diferentes pontos das cidades, em função de seu tamanho, com o objetivo de avaliar, naquele instante, a situação de fluoretação da água de abastecimento. Os resultados mostraram que 31 (45,6//) cidades não apresentam água fluoretada, 17 cidades (25,0//) apresentam teor de fluoreto de 0,1 a 0,5 ppm, 13 cidades (19,1//) com 0,5 a 0,7 ppm e 7 cidades (10,3//) com concentração de fluoreto na faixa de 0,7 a 1,0 ppm