Influence of intraradicular post and crown ferrule on the fracture strength of endodontically treated teeth

The aim of this study was to investigate the fracture strength of endodontically treated teeth restored with different posts and variable ferrule heights. Sixty freshly extracted human canines were treated endodontically and randomly assigned to 6 groups (n=10), being restored with custom-made cast post-and-core (CP0 and CP3 groups), prefabricated post and composite resin core (PF0 and PF3 groups), and composite resin (CR0 and CR3 groups). The CP0, PF0 and CR0 groups presented no ferrule and the CP3, PF3 and CR3 presented 3 mm of coronal structure. All teeth were restored with full metal crowns. The fracture strength was measured in a universal testing machine at 45o to the long axis of the tooth until failure. Data were analyzed statistically by 2-way ANOVA and Tukey's test (?=0.05). When the mean fracture strength values were compared (CP0 group - 820.20 N, CP3 group - 1179.12 N; PF0 group - 561.05 N; PF3 group - 906.79 N; CR0 group - 297.84 N; and CR3 group - 1135.15 N) there was statistically significant among the groups (p<0.05), except for the three groups with 3 mm of coronal remaining, which were similar to each other. The results of this study showed that the ferrule in crowns promoted significantly higher fracture strength in the endodontically treated teeth.

Effect of different ferrule designs on the fracture resistance and failure pattern of endodontically treated teeth restored with fiber posts and all-ceramic crowns

OBJECTIVE: This study investigated the effect of different ferrule heights on endodontically treated premolars. MATERIAL AND METHODS: Fifty sound mandibular first premolars were endodontically treated and then restored with 7-mm fiber post (FRC Postec Plus #1 Ivoclar-Vivadent) luted with self-polymerized resin cement (Multilink, Ivoclar Vivadent) while the coronal section was restored with hybrid composite core build-up material (Tetric Ceram, Ivoclar-Vivadent), which received all-ceramic crown. Different ferrule heights were investigated: 1-mm circumferential ferrule without post and core (group 1 used as control), a circumferential 1-mm ferrule (group 2), non-uniform ferrule 2-mm buccally and 1-mm lingually (group 3), non-uniform ferrule 3-mm buccally and 2-mm lingually (group 4), and finally no ferrule preparation (group 5). The fracture load and failure pattern of the tested groups were investigated by applying axial load to the ceramic crowns (n=10). Data were analyzed statistically by one-way ANOVA and Tukey's post-hoc test was used for pair-wise comparisons (α=0.05). RESULTS: There were no significant differences among the failure load of all tested groups (P<0.780). The control group had the lowest fracture resistance (891.43±202.22 N) and the highest catastrophic failure rate (P<0.05). Compared to the control group, the use of fiber post reduced the percentage of catastrophic failure while increasing the ferrule height did not influence the fracture resistance of the restored specimens. CONCLUSIONS: Within the limitations of this study, increasing the ferrule length did not influence the fracture resistance of endodontically treated teeth restored with glass ceramic crowns. Insertion of a fiber post could reduce the percentage of catastrophic failure of these restorations under function.

Comparação das dimensões de tecido mole entre padrões faciais distintos

OBJETIVO: o presente estudo destinou-se a comparar a morfologia tegumentar de indivíduos segundo a tipologia facial. MÉTODOS: foram utilizadas 90 telerradiografias de pacientes de ambos os sexos, de 12 a 16 anos de idade, divididas em três grupos distintos, referentes a cada padrão morfológico: mesofacial, dolicofacial e braquifacial. Os grupos foram comparados no que se refere às medidas de espessura e altura do lábio superior e inferior, além da espessura do mento mole. Ainda, foi apurada a presença de correlações entre as variáveis de tecido mole avaliadas e medidas cefalométricas de natureza dentária e esquelética. RESULTADOS E CONCLUSÕES: os lábios superiores e inferiores, assim como o mento mole, não apresentaram diferenças em relação às suas espessuras em todos os grupos morfológicos. Porém, as alturas do lábio superior e inferior foram significativamente maiores para os dolicofaciais quando esses foram comparados aos demais grupos. Braquifaciais apresentaram menor altura do lábio superior quando comparados aos mesofaciais, embora ambos não tenham se diferenciado significativamente no que se refere à altura do lábio inferior. A análise das correlações estabelecidas entre as variáveis dos tecidos moles e duros indicou evidências de um desenvolvimento vertical dos lábios superior e inferior em acompanhamento ao desenvolvimento vertical do esqueleto. O posicionamento vertical do incisivo superior se correlacionou significativamente aos mesmos parâmetros labiais, o que garantiu um nível de exposição semelhante desse elemento dentário em todos os grupos.

Estudo das características cefalométricas em adolescentes brasileiros portadores de Padrão Face Longa

OBJETIVO: definir valores cefalométricos esqueléticos e dentários para adolescentes brasileiros com Padrão Face Longa. MÉTODOS: a amostra foi constituída de telerradiografias em norma lateral de 30 pacientes com Face Longa, sendo 17 do sexo feminino e 13 do masculino; e 30 pacientes face Padrão I, 15 do sexo masculino e 15 do feminino, no estágio de dentadura permanente durante a adolescência. As características do Padrão Face Longa foram definidas clinicamente, pela análise facial. As seguintes grandezas cefalométricas foram avaliadas: (1) Comportamento sagital das bases apicais (SNA, SNB, ANB, NAP, Co-A, Co-Gn); (2) Comportamento vertical das bases apicais (SN.PP, SN.PM, ângulo goníaco, AFAT, AFAI, AFAM, AFP, AFATperp, AFAIperp); (3) Comportamento dentoalveolar (1-PP, 6-PP, 1-PM, 6-PM, 1.PP, IMPA); e (4) Proporção entre as alturas faciais (AFAIPerp/AFATPerp, AFAI/AFAT, AFAM/AFAI). RESULTADOS E CONCLUSÕES: o erro vertical na Face Longa concentra-se no terço inferior. A maxila apresenta uma maior altura dentoalveolar e a mandíbula, com morfologia mais vertical, mostra maior rotação no sentido horário. Essas características morfológicas e espaciais acarretam alterações sagitais e verticais no esqueleto e alterações verticais dentoalveolares. No sentido sagital, os ângulos de convexidade facial estão aumentados. No sentido vertical, as alturas faciais anteriores total e inferior estão aumentadas. O componente dentoalveolar está mais longo.

Isotopic view of vegetation and carbon and nitrogen cycles in a cerrado ecosystem, southeastern Brazil

Carbon and nitrogen biogeochemical cycles in savannas are strongly regulated by the seasonal distribution of precipitation and pulses of nutrients released during the wetting of the dry soil and are critical to the dynamics of microorganisms and vegetation. The objective of this study was to investigate the spatial and temporal variability of C and N isotope ratios as indicators of the cycling of these elements in a cerrado sensu stricto area, within a protected area in a State Park in the state of São Paulo, Brazil. The foliar δ13C and δ15N values varied from -33.6 to -24.4 ‰ and -2.5 to 4.5 ‰, respectively. The δ13C values showed a consistent relationship with canopy height, revealing the importance of structure of the canopy over the C isotopic signature of the vegetation. Carbon isotopic variations associated with the length of the dry season indicated the importance of recent fixed C to the integrated isotopic signature of the leaf organic C. The studied Cerrado species showed a depleted foliar δ15N, but a wide range of foliar Nitrogen with no difference among canopy heights. However, seasonal variability was observed, with foliar δ15N values being higher in the transition period between dry and rainy seasons. The variation of the foliar C and N isotope ratios presented here was consistent with highly diverse vegetation with high energy available but low availability of water and N.

Relação entre percepção e ação durante os movimentos de sentar e levantar em indivíduos idosos

A proposta deste estudo foi analisar o efeito do envelhecimento nos aspectos perceptivos e motores envolvidos com as ações de sentar e levantar de uma cadeira. Indivíduos jovens e idosos foram filmados enquanto sentavam/levantavam de uma cadeira em sete alturas diferentes do assento. Eles julgaram a dificuldade/facilidade encontrada para sentar e levantar em cada altura do assento. Os idosos exibiram mudanças na estratégia de controle usada para sentar na altura mais baixa do assento e superestimaram o nível de dificuldade/facilidade para realizar as tarefas de sentar e levantar. Em síntese, a percepção de execução fácil da tarefa de sentar pelos idosos não concorda com o grau de dificuldade exibido no desempenho motor na altura mais baixa do assento.

Utilização de métodos acústicos em estudos de dinâmica costeira: exemplo na desembocadura lagunar de cananéia

Em função de suas condições de interface entre águas doces e salinas, desembocaduras estuarinas e lagunares constituem sistemas geomorfológicos altamente complexos e dinâmicos. Como conseqüência da variabilidade espacial e temporal dos fluxos de maré, o leito responde com uma grande variabilidade nas características morfológicas e sedimentares. Neste sentido, é possível relacionar diretamente a circulação de fundo e o transporte sedimentar com as feições submersas geradas. Perfis de ecossondagem, sonar de varredura lateral e sísmica de alta resolução, executados na desembocadura lagunar de Cananéia, revelaram a existência de uma dinâmica de fundo extremamente complexa, caracterizada por marcas onduladas e ondas de areia de alturas métricas. As maiores ondas de areia, localizadas em uma depressão na desembocadura lagunar, apresentam inversão de polaridade em sua assimetria, com a presença de ondas simétricas de grande tamanho no ponto de inversão. Este padrão morfológico não apresenta variação temporal em escala anual, sugerindo a persistência de um padrão de fluxos sobre o leito. Esta dinâmica revela, também, a constância de fluxos convergentes que aparentemente independem das condições de maré enchente ou vazante. Os resultados permitiram o estabelecimento de um primeiro modelo qualitativo de circulação de fundo na área, com aplicações potenciais na navegação e estudos de proteção da costa.

Haptic Stabilization of Posture in Adults With Intellectual Disabilities Using a Nonrigid Tool

This study assessed the effects of haptic information on the postural control systems of individuals with intellectual disabilities (ID), through the use of a nonrigid tool that we call the ""anchor system"" (e.g., ropes attached to graduated weights that rest on the floor). Eleven participants with ID were asked to stand, blindfolded, on a balance beam placed at two heights (10 and 20 cm), for 30 s, while using the anchor system at two weights. The lighter anchor weight appeared to improve the individuals' balance in contrast to a control task condition; therefore, we concluded that haptic sensitivity was more significant in helping to orient the body than was the anchor's mechanical support alone.

An Evaluation of Different Bioreactor Configurations with Immobilized Yeast for Bioethanol Production

The bioethanol industry expects a huge expansion and new technologies are being implemented with the aim of optimizing the fermentation process. The behavior of cells of Saccharomyces cerevisiae immobilized in PVA-LentiKats, during the production of bioethanol in two reactor systems, was studied. The entrapped cell in LentiKats lenses showed a different profile using stirred tank reactor (STR) and packed column reactor (PCR). Low free cells accumulation in the medium was observed for the STR after 72 h of fermentation. On the other hand, no free cells accumulation was observed, probably due to the absence of mechanical agitation in PCR configuration. Better fermentation results were obtained working with STR (final cellular concentration = 13 g.L-1, Pf = 28 g.L-1, Qp = 1.17 g.L-1.h-1,and Yp/s = 0.3 g.g-1) in comparison to PCR (final cellular concentration = 11.4 g.L-1, Pf = 20 g.L-1, Qp = 0.83 g.L-1.h-1,and Yp/s = 0.25 g.g-1). Such results are probably due to the mechanical agitation of the medium provided by STR configuration, which permitted a better heat and mass transference.

Biomass Refinery as a Renewable Complement to the Petroleum Refinery

Biomass Refinery is a sequential of eleven thermochemical processes and one biological process with two initial basic treatments: prehydrolysis for lignocellulosics and low temperature conversion for biomass with medium-to-high content of lipids and proteins. The other ten processes are: effluent treatment plant, furfural plant, biodiesel plant, cellulignin dryer, calcination, fluidized bed boiler, authotermal reforming of cellulignin for syngas production, combined cycle of two-stroke low-speed engine or syngas turbine with fluidized bed boiler heat recovery, GTL technologies and ethanol from cellulose, prehydrolysate and syngas. Any kind of biomass such as wood, agricultural residues, municipal solid waste, seeds, cakes, sludges, excrements and used tires can be processed at the Biomass Refinery. Twelve basic products are generated such as cellulignin, animal feed, electric energy, fuels (ethanol, crude oil, biodiesel, char), petrochemical substitutes, some materials (ash, gypsum, fertilizers, silica, carbon black) and hydrogen. The technology is clean with recovery of energy and reuse of water, acid and effluents. Based on a holistic integration of various disciplines Biomass Refinery maximizes the simultaneous production of food, electric energy, liquid fuels and chemical products and some materials, achieving a competitive position with conventional and fossil fuel technologies, as well as payment capacity for biomass production. Biomass Refinery has a technical economical capability to complement the depletion of the conventional petroleum sources and to capture its GHGs resulting a biomass + petroleum ""green"" combination.

Production of Cellulolytic Enzymes by Anaerobic Fungi Cultivated in Different Conditions

The present paper studies the influence of different nutrients for the production of two cellulolytic enzymes: endo beta-1.4 glucanase and exo beta-1.4 glucanase by anaerobic fungi taken from cow rumen, that were fed a diet of corn silage and Brachiaria decumbens grass hay. During the enzymatic degradation assays, it was observed that the addition of some essential nutrients in the formulation of the culture medium contributed positively in the cellulolytic enzyme production, with exception of riboflavin. Such results contributed in the establishment of an effective method for the evaluation of enzymatic activities in anaerobic fibrolytic fungi. In this work, nutrients added to enrich the culture medium have successfully proven that they can be used as inoculating agents (inductors) in diets rich in ensilage with law nutritive value.

Fermentation of Groundnut Shell Enzymatic Hydrolysate for Fuel Ethanol Production by Free and Sorghum Stalks Immobilized Cells of Pichia stipitis NCIM 3498

Groundnut shell (GS), after separation of pod, is readily available as a potential feedstock for production of fermentable sugars. The substrate was delignified with sodium sulfite. The delignified substrate released 670 mg/g of sugars after enzymatic hydrolysis (50 degrees C, 120 rpm, 50 hrs) using commercial cellulases (Dyadic Xylanase PLUS, Dyadic Inc. USA). The groundnut shell enzymatic hydrolysate (45.6 g/L reducing sugars) was fermented for ethanol production with free and sorghum stalks immobilized cells of Pichia stipitis NCIM 3498 under submerged cultivation conditions. Immobilization of yeast cells on sorghum stalks were confirmed by scanning electron microscopy (SEM). A maximum of ethanol production (17.83 g/L, yield 0.44 g/g and 20.45 g/L, yield 0.47 g/g) was observed with free and immobilized cells of P. stipitis respectively in batch fermentation conditions. Recycling of immobilized cells showed a stable ethanol production (20.45 g/L, yield 0.47 g/g) up to 5 batches followed by a gradual downfall in subsequent cycles.

Rheological Properties of Chocolate Drink from Cupuassu

Flow behavior of chocolate drinks from Cupuassu (Theobroma grandiflorum, Sterculiaceae) from instantised and normal formulation, and enriched with calcium, were studied. Flow behavior was described using common rheological models (Newton, Power Law, and Bingham plastic). Experimental results, obtained at 25 degrees C and 40 degrees C, fitted mostly the Ostwald and Bingham models, with R(2) >= 0.997. The Newtonian model has 0.886 >= R(2) >= 0.991. At 25 degrees C, as expected, viscosity of samples was higher and pseudoplasticity increased (n values were lower than 1). The spray-dryer process lead to differences of rheology of the ""chocolate"" milk drinks. The addition of microcrystalline cellulose plus calcium leads to a lower viscosity.

Use of Cassava Peel as Carbon Source for Production of Amylolytic Enzymes by Aspergillus niveus

Aspergillus niveus produced high levels of alpha-amylase and glucoamylase in submerged fermentation using the agricultural residue cassava peel as a carbon source. In static conditions, the amylase production was substantially greater than in the agitated condition. The optimized culture conditions were initially at pH 5.0, 35 degrees C during 48 hours. Amylolytic activity was still improved (50%) with a mixture of cassava peel and soluble starch in the proportion 1:1 (w/w). The crude extract exhibited temperature and pH optima approximately 70 degrees C and 4.5, respectively. Amylase activity was stable for 1 h at 60 degrees C, and at pH values between 3.0 and 7.0. The enzyme hydrolysed preferentially maltose, starch, penetrose, amylose, isomaltose, maltotriose, glycogen and amylopectin, and not hydrolysed cyclodextrin (alpha and beta), trehalose and sucrose. In the first hour of reaction on soluble starch, the hydrolysis products were glucose and maltose, but after two hours of hydrolysis, glucose was the unique product formed, confirming the presence in the crude extract of an alpha-amylase and a glucoamylase.

Disequilibrium Coefficient: A Bayesian Perspective

Hardy-Weinberg Equilibrium (HWE) is an important genetic property that populations should have whenever they are not observing adverse situations as complete lack of panmixia, excess of mutations, excess of selection pressure, etc. HWE for decades has been evaluated; both frequentist and Bayesian methods are in use today. While historically the HWE formula was developed to examine the transmission of alleles in a population from one generation to the next, use of HWE concepts has expanded in human diseases studies to detect genotyping error and disease susceptibility (association); Ryckman and Williams (2008). Most analyses focus on trying to answer the question of whether a population is in HWE. They do not try to quantify how far from the equilibrium the population is. In this paper, we propose the use of a simple disequilibrium coefficient to a locus with two alleles. Based on the posterior density of this disequilibrium coefficient, we show how one can conduct a Bayesian analysis to verify how far from HWE a population is. There are other coefficients introduced in the literature and the advantage of the one introduced in this paper is the fact that, just like the standard correlation coefficients, its range is bounded and it is symmetric around zero (equilibrium) when comparing the positive and the negative values. To test the hypothesis of equilibrium, we use a simple Bayesian significance test, the Full Bayesian Significance Test (FBST); see Pereira, Stern andWechsler (2008) for a complete review. The disequilibrium coefficient proposed provides an easy and efficient way to make the analyses, especially if one uses Bayesian statistics. A routine in R programs (R Development Core Team, 2009) that implements the calculations is provided for the readers.