Effect of different dental composite resins on the polymerization process

Dental composite resins possess good esthetic properties, and are currently among the most popular dental restorative materials. Both organic and inorganic phases might influence the material behavior, the filler particle features and rate are the most important factors related to improvement of the mechanical properties of resin composites. Thus, the objective of this study was to evaluate the effect of three different composite resins on the polymerization process by Vickers hardness test. The samples were prepared using three different composite resins, as follow: group I-P-60 (3M/ESPE); group II-Herculite XRV (Kerr), and group III-Durafill (Heraeus-Kulzer). The samples were made in a polytetrafluoroethylene mould, with a rectangular cavity measuring 7 mm in length, 4 mm in width, and 3 mm in thickness. The samples were photo-activated by one light-curing unit based on blue LEDs (Ultrablue III-DMC/Brazil) for 20 and 40 s of irradiation times. The Vickers hardness test was performed 24 h after the photo-activation until the standardized depth of 3 mm. The Vickers hardness mean values varied from 158.9 (+/- 0.81) to 81.4 (+/- 1.94) for P-60, from 138.7 (+/- 0.37) to 61.7 (+/- 0.24) for Herculite XRV, and from 107. 5 (+/- 0.81) to 44.5 (+/- 1.36) for Durafill composite resins photo-activated during 20 s for the 1st and 2nd mm, respectively. During 40 s of photo-activation, the Vickers hardness mean values were: from 181.0 (+/- 0.70) to 15.6 (+/- 0.29) for P-60, and from 161.8 (+/- 0.41) to 11.2 (+/- 0.17) for Herculite XRV composite resins, for the 1st and 3th mm, respectively. For Durafill composite resin the mean values varied from 120.1 (+/- 0.66) to 61.7 (+/- 0.20), for the 1st and 2nd mm, respectively. The variation coefficient (CV) was in the most of the groups lower than 1%, then the descriptive statistic analysis was used. The Vickers hardness mean values for Durafill were lower than P-60 and Herculite XRV composite resins for 20 and 40 s of irradiation time. The polymerization process was greatly affected by the composition of the composite resins.

Bond Strength and Etching Pattern of Adhesive Systems to Enamel: Effects of Conditioning Time and Enamel Preparation

Statement of the problem: The performance of self-etch systems on enamel is controversial and seems to be dependent on the application technique and the enamel preparation. Purpose of the Study: To examine the effects of conditioning time and enamel surface preparation on bond strength and etching pattern of adhesive systems to enamel. Materials and Methods: Ninety-six teeth were divided into 16 conditions (N = 6) in function of enamel preparation and conditioning time for bond strength test. The adhesive systems OptiBond FL (Kerr, Orange, CA, USA), OptiBond SOLO Plus (Kerr), Clearfil SE Bond (Kuraray, Osaka, Japan), and Adper Prompt L-Pop (3M ESPE, St. Paul, MN, USA) were applied on unground or ground enamel following the manufacturers` directions or doubling the conditioning time. Cylinders of Filtek Flow (0.5-mm height) were applied to each bonded enamel surface using a Tygon tube (0.7 mm in diameter; Saint-Gobain Corp., Aurora, OH, USA). After storage (24 h/37 degrees C), the specimens were subjected to shear force (0.5 mm/min). The data were treated by a three-way analysis of variance and Tukey`s test (alpha = 0.05). The failure modes of the debonded interfaces and the etching pattern of adhesives were observed using scanning electron microscopy. Results: Only the main factor ""adhesive"" was statistically significant (p < 0.001). The lowest bond strength value was observed for OptiBond FL. The most defined etching pattern was observed for 35% phosphoric acid and for Adper Prompt L-Pop. Mixed failures were observed for all adhesives, but OptiBond FL showed cohesive failures in resin predominantly. Conclusions: The increase in the conditioning time as well as the enamel pretreatment did not provide an increase in the resin-enamel bond strength values for the studied adhesives. CLINICAL SIGNIFICANCE The surface enamel preparation and the conditioning time do not affect the performance of self-etch systems to enamel. (J Esthet Restor Dent 20:322-336, 2008)

Thermal characterization of dental composites by TG/DTG and DSC

Dental composites can be improved by heat treatment, as a possible way to increase mechanical properties due to additional cure (post-cure). Direct dental composites are essentially similar to the indirect ones, supposing they have the same indication. Therefore, to establish a heat treatment protocol for direct composites, using as indirect (photoactivated by continuous and pulse-delay techniques), a characterization (TG/DTG and DSC) is necessary to determine parameters, such as mass loss by thermal decomposition, heat of reaction and glass transition temperature (T (g)). By the results of this study, a heat treatment could be carried out above 160 A degrees C (above T (g), and even higher than the endset exothermic event) and under 180 A degrees C (temperature of significant initial mass loss).

Justiça restaurativa: uma possível alternativa a pena de prisão e sua utilização pelo poder judiciário

O presente trabalho tem por finalidade estudar a Justiça Restaurativa como uma alternativa a pena de prisão e sua utilização pelo Poder Judiciário. O trabalho foi realizado pelo modelo plan francês, desenvolvido em duas partes, uma parte teórica e uma prática; cada uma das partes foi dividida em dois capítulos. Na parte teórica, no primeiro capítulo foi estudada a justiça restaurativa, seus conceitos e peculiaridades, além de sua contextualização no universo jurídico. No segundo capítulo foram estudados os institutos da mediação e da conciliação, bem como à aproximação dos referidos institutos da justiça restaurativa. Na segunda parte, a prática; primeiramente abordamos o Projeto de Lei nº 7006/2006, que visa introduzir a Justiça Restaurativa em nosso sistema penal de forma institucionalizada e a Resolução nº 125 do Conselho Nacional de Justiça (CNJ). No segundo capítulo analisamos os programas de justiça restaurativa existentes no Brasil, a criação dos Núcleos de Mediação pelo Tribunal de Justiça do Estado do Rio de Janeiro; mapeamos a justiça restaurativa no Estado do Rio de Janeiro e não identificamos nenhum projeto em andamento. E por fim analisamos os indícios da Justiça Restaurativa existentes no Juizado Especial Criminal (JECRIM) da Barra da Tijuca, onde esse tipo de procedimento não existe de forma estruturada. Não existe um programa que dê aporte a prática, sendo utilizada, quando possível, como mais um instrumento para resolução dos conflitos, por meio da mediação penal.

Suco de laranja e vitamina C : efeito sobre a estabilidade genômica

Existem evidências crescentes indicando a associação entre dietas ricas em frutas e vegetais e a diminuição da incidência de câncer. O suco de laranja (OJ) pode ser incluído entre os alimentos com potencial quimioprotetor e seu estudo é muito relevante pelo amplo consumo desta bebida. O OJ possui vários nutrientes e compostos bioativos com atividades antioxidante, antimutagênica, anticarcinogênica e antiaterogênica, entre outras. A vitamina C (Vit C) é um dos nutrientes mais abundantes no OJ, e o único nutriente que pode ser provido em quantidade superior à recomendação diária por uma única porção de 200 mL de OJ. A Vit C, a exemplo de outros componentes do OJ, pode ser tanto benéfica quanto maléfica para os sistemas biológicos, dependendo do contexto metabólico. Neste sentido, vários nutrientes presentes no OJ têm sido identificados como mutagênicos ou carcinogênicos, especialmente quando administrados de forma isolada. Este estudo utilizou o ensaio Cometa alcalino em sangue de camundongos (in vivo) para avaliar: 1) a genotoxicidade do OJ e da Vit C; 2) a genotoxicidade do FeSO4 e do CuSO4: 3) o efeito modulador do OJ e da Vit C sobre a genotoxicidade do FeSO4 e CuSO4, bem como do metilmetanosulfonato (MMS) e da ciclofosfamida (CP). A versão alcalina do ensaio Cometa foi utilizada para avaliar o dano no DNA em células brancas do sangue periférico de camundongos. Adicionalmente, os níveis de cobre e ferro no sangue e no fígado dos camundongos tratados com metais e OJ foram avaliados pela metodologia de PIXE (Particle-Induced X-ray Emission). Grupos com pelo menos 6 camundongos (metade de cada sexo) foram tratados por gavage com uma ou duas doses de água (controle), CP, MMS, FeSO4 ou CuSO4. OJ (0.1 mL/Kg) foi administrado tanto antes (pré-tratamento) quanto após a administração das substâncias-teste (pós-tratamento). A Vit C (1 e 30 mg/Kg) foi administrada apenas no pós-tratamento. O dano no DNA foi avaliado 24 e 48 h após o início do tratamento. Após 24 h, o OJ induziu um suave aumento no dano no DNA, enquanto a Vit C foi genotóxica (30 mg/Kg > 1 mg/Kg). O tratamento duplo com Vit C (a 0 e a 24 h) induziu uma resposta genotóxica cumulativa a 48 h, que foi mais intensa para a dose maior. O FeSO4 e o CuSO4 foram genotóxicos após 24 h, mas tiveram seu dano efetivamente reparado após 48 h do tratamento. O pré-tratamento com OJ reduziu a genotoxicidade do FeSO4 e do CuSO4 (efeito preventivo). O pós-tratamento com OJ também reduziu a genotoxicidade do CuSO4 (efeito reparador). O OJ mostrou tanto efeito preventivo quanto reparador sobre a genotoxicidade do MMS. O OJ teve apenas efeito reparador sobre a CP. Ambas doses de Vit C aumentaram os danos no DNA causados pelo FeSO4 e pelo CuSO4. Adicionalmente, os níveis de cobre e ferro no sangue e no fígado dos camundongos tratados com metais e OJ foram avaliados pela metodologia de PIXE (Particle-Induced X-ray Emission). Grupos com pelo menos 6 camundongos (metade de cada sexo) foram tratados por gavage com uma ou duas doses de água (controle), CP, MMS, FeSO4 ou CuSO4. OJ (0.1 mL/Kg) foi administrado tanto antes (pré-tratamento) quanto após a administração das substâncias-teste (pós-tratamento). A Vit C (1 e 30 mg/Kg) foi administrada apenas no pós-tratamento. O dano no DNA foi avaliado 24 e 48 h após o início do tratamento. Após 24 h, o OJ induziu um suave aumento no dano no DNA, enquanto a Vit C foi genotóxica (30 mg/Kg > 1 mg/Kg). O tratamento duplo com Vit C (a 0 e a 24 h) induziu uma resposta genotóxica cumulativa a 48 h, que foi mais intensa para a dose maior. O FeSO4 e o CuSO4 foram genotóxicos após 24 h, mas tiveram seu dano efetivamente reparado após 48 h do tratamento. O pré-tratamento com OJ reduziu a genotoxicidade do FeSO4 e do CuSO4 (efeito preventivo). O pós-tratamento com OJ também reduziu a genotoxicidade do CuSO4 (efeito reparador). O OJ mostrou tanto efeito preventivo quanto reparador sobre a genotoxicidade do MMS. O OJ teve apenas efeito reparador sobre a CP. Ambas doses de Vit C aumentaram os danos no DNA causados pelo FeSO4 e pelo CuSO4. processado e armazenado de forma a preservar o seu potencial biológico é um alimento sugerido como uma das porções de uma dieta equilibrada (contendo pelo menos 5 porções de frutas e vegetais), recomendada para uma vida saudável e longeva.

Justiça restaurativa: um modelo democrático de reforma institucional?

Este artigo se propõe a refletir acerca da justiça restaurativa como um paradigma possível de reforma institucional no contexto brasileiro, diante dos inúmeros problemas estruturais existentes no sistema prisional. Inicialmente, será apresentado um diagnóstico da situação atual do sistema carcerário brasileiro e de impactos sofridos pelos indivíduos em cumprimento de pena privativa de liberdade. Em seguida, serão levantadas algumas possibilidades de reformas apresentadas por estudiosos e policy makers. Por fim, será apresentada a justiça restaurativa como alternativa ao modelo de justiça retributiva tradicional. A partir de uma breve explicitação do seu conceito e de seus valores, o objetivo é pensar se essa nova forma de lidar com o delito pode contribuir para um sistema de justiça criminal mais participativo e democrático, apontando-se desafios à implementação desse paradigma de justiça no Brasil. No final do texto, é feito um balanço da discussão apresentada, concluindo-se que a adoção da justiça restaurativa como possível reforma do sistema de justiça criminal brasileiro parece promissora, ainda que adotada de forma experimental e incremental e carente de estudos mais aprofundados que levem em conta as particularidades do país.

Novos monômeros obtidos a partir do metacrilato de glicidila, bisfenol A e 4, 4 isopropilidenodicicloexanol : síntese, caracterização estrutural e propriedades de compósitos para utilização em resinas de restauração dental

Nowadays, composite resins are the direct restorative materials more important in dental clinical performance, due to their versatility and aesthetic excellence. Bis-GMA (2,2-bis[4(2-hydroxy-3-metacryloxypropoxy)phenil]propane) is the base monomer more frequently used in restorative composite resins. However, this monomer presents some disadvantages, such as high viscosity and two aromatic rings in its structure that can promote allergic reactions to the humans. In this work, the main purpose was to synthesize new monomers from glycidyl methacrylate to use in dental restorative materials. Structural characterization of the monomers was carried out through FTIR and NMR 1H, and eight composites were produced from the new monomers, by addition of silane-treated alumino silicate particles (inorganic filler) and a photocuring system (camphorquinone and ethyl 4-dimethylaminebenzoate). The composites were analyzed by environmental scanning electronic microscopy and the water sorption and solubility, compressive strength and elastic modulus were determined. A commercial composite resin [Z100 (3M)] was used to comparison effect. The new composites presented general characteristics similar to the commercial ones; however, they didn t present the properties expected. This behavior was attributed to the lower degree of monomer reaction and to the granulometry and size distribution of the mineral filler in the polymeric matrix

Justiça restaurativa no sistema penal e processual penal como forma de concretização do estado democrático constitucional

Diante do atual modelo penal e processual penal não atender aos reclamos das partes interessadas, gerando um descrédito na Justiça de um modo geral, surge a Justiça Restaurativa como uma alternativa para solucionar tais problemas e como elemento de concretização do Estado Democrático Constitucional. A Constituição Federal de 1988 representa o símbolo maior do processo de democratização e de constitucionalização nacional. O Princípio da Dignidade da Pessoa contida no texto constitucional consiste num dos principais fundamentos da República Federativa do Brasil, funcionando como respaldo aos direitos e garantias fundamentais do cidadão, sobretudo na seara criminal. A partir do processo de constitucionalização nacional, ocorre uma releitura das legislações infra-constitucionais, que passam a ser interpretadas de acordo com o texto constitucional. Atualmente, a conjuntura jurídico-penal pátria está associada à ideia de garantismo, ligada ao conceito de Estado Democrático Constitucional. Apresenta-se a Justiça Restaurativa como um novo modelo de Justiça Penal, mais flexível e humanizado, visando além da aplicação da pena imposta pelo Estado, superar uma situação de conflito, na busca por resultados positivos no combate e redução da criminalidade, a satisfação da vítima e a mudança da cultura de violência, compatível com as diretrizes do Estado Democrático Constitucional. A partir da análise do direito internacional e de projetos e legislações nacionais envolvendo a Justiça Restaurativa, percebe-se a eficácia das medidas restaurativas na solução de conflitos dentro do Processo Penal, além da satisfação da vítima, do infrator e de familiares na participação dos encontros restaurativos, constituindo ferramenta de satisfação da dignidade humana, dentro de uma perspectiva humanista e garantista

A palavra cantada nos espaços intersubjetivos de um centro de atenção psisossocial do município do Natal/RN

The psychiatric care and mental health are undergoing constant change over the History. The Brazilian Psychiatric Reform, which brings up the deinstitutionalization as a structuring in the restorative care process. The Reform has as one of the mainly substitutive services the Centers for Psychosocial Care (CAPS), which work from the Singular Therapeutic Project (PTS) in order to restore the autonomy and restore the dignity of users. The therapeutic workshop is some of the resources used and work several kinds of activities as: writing, handcraft, music, poetry, and so forth. This study set up to apprehend the social representations of helping of the music workshop carried out in the CAPS II east of Natal/RN, from the reports given by the participants of the workshop, using the focal group as technique. This is a descriptive exploratory study with a qualitative approach. A total of 16 users participated in four musical therapeutic workshops from April to May 2010. The study was approved by the Ethics and Research Committee of UFRN. The discursive material from the workshop was submitted to the informational resource of Analyse Lexicale par Contexte d um Ensemble de Segments de Texte, ALCESTE, and analyzed based on the Theory of Representations and the Central Core Theory. The majority of subjects were men (62.5%), single (62.5%), aged 40-49 years (37.6%) and elementary school level (56.2 %). The reports were transcribed and submitted to the classification system of ALCESTE, which elected the following categories: Category 1 - Experience in the Word Family Sung, Category 2 - Musical Experiences and Approaches, and Category 3 - Feelings and emotions evoked by music. The representation of these individuals is anchored in the experience they have with the CAPS, lived and socialized by common sense, through this particular social group workshop objectified in music therapy as a therapeutic modality enjoyable. The central core revealed the intrinsic relationship between users and the music, establishing a relationship of openness to use the same while its therapeutic use in workshops of substitute services for mental health. Peripherals elements issues are related to listen, share and experience music in the family. Intermediary Elements relate to the feelings and emotions evoked by music, given her close relationship with it. It was found in the study that music can be construed as an artifact of good therapeutic responsiveness to users, configuring it as an invigorating and enjoyable therapy, confirming the need for continuity of this activity, as well as its expansion into the service

Atuação profissional e vivência do cirurgião-dentista na estratégia do programa de saúde da família

The purpose of this research was to analyze the working profile of dentists from the Family Health Program (PSF Programa de Saúde da Família, Brasil) of some Municipal Districts of Rio Grande do Norte (Brazil) in order to understand the way they handle the experience acquired with the work developed in that Program. This discussion evolves a reflection about the perspectives of consolidation of the FHP as well as the possible advancements of the Brazilian Unified Health System (SUS - Sistema Único de Saúde). The target population was composed of dentists from the FHP of Rio Grande do Norte. Thus we performed twenty-one interviews orientated by a semi-structured guidebook with open questions and identification data. We opted for recording the speech of all the professionals in order to ensure the accuracy of the information gathered. The main results found were: predominance in the female gender; the majority of dentists has no post graduation courses; in those few cases of dentists with some post-graduation a lack of correlation with Public or Collective Health was observed; the dentists interviewed present a profile directed to clinical activities; the dentists used to develop basic restorative and periodontic treatment, simple surgeries and educative and preventive activities, even though the last two ones are carried out in an extremely traditional way (lectures and topical application of fluoride). In addition, as biggest difficulties to manage the work dentists pointed out the lack of permanent and consumer material, inadequate infrastructure, no transport to take them to distant places, no integration with the Health Family Team, technical difficulty such to perform educative and preventive activities as to provide adequate service to a repressed lawsuit. The results indicate the existence of a necessity to lead them to reflect and redirect their practices. In order to reach this aim it must be considered as initial measure the investment and encouragement toward to permanent education as well as a close follow-up and evaluation of the actions developed by them

Praça: lugar de lazer: relações entre características ambientais e comportamentais na Praça Kalina Maia Natal RN

Nowadays, the urban chaos brings some problems to the citizens such as mental fatigue, irritability and lack of attention, emphasizing the need for open urban spaces, capable to contribute to the restoration of physical and mental balance of people. By the variety of alternative uses available, many of them related to the stimulus of entertainment activities, the squares have been identified as restorative environments, especially by its potential as a place of leisure. In this context, the objective of this dissertation is to understand the use of the square as leisure environment, by a square in Natal RN, establishing the relationship between environmental and behavioral characteristics. More specifically, I attempt to identify the major activities that happen there, the people that develop them and the spatial and temporal configurations of this occupation. Among the 290 squares available in the city, the Kalina Maia Square was selected, which is located in the district of Lagoa Nova. The case study chosen was based on criteria relating to scale, shape, location on the urban environment, variability of uses and conservation status. In the study were used behavioral mapping place-centered and people-centered, behavior trace analysis and 14 interviews. The results show that the square is used by people from different ages and social classes, subdivided into groups with specific days and times. These users are usually engaged in activities related to various types of leisure, with sports predominance. The relationship between spatial configuration and behavior shows that there is a sectorization of uses, being possible to identify the environmental characteristics that most favor observed activities, especially in relation to shading and presence of furniture and equipment. Moreover, throughout the day it appears that the affordances inherent to the various fixed objects on the square are decoded differently by various categories of users, by giving them insights that help the development of leisure activities that characterize each group

Stability analysis of power systems described with detailed models by automatic method

The power system stability analysis is approached taking into explicit account the dynamic performance of generators internal voltages and control devices. The proposed method is not a direct method in the usual sense since conclusion for stability or instability is not exclusively based on energy function considerations but it is automatic since the conclusion is achieved without an analyst intervention. The stability test accounts for the nonconservative nature of the system with control devices such as the automatic voltage regulator (AVR) and automatic generation control (AGC) in contrast with the well-known direct methods. An energy function is derived for the system with machines forth-order model, AVR and AGC and it is used to start the analysis procedure and to point out criticalities. The conclusive analysis itself is made by means of a method based on the definition of a region surrounding the equilibrium point where the system net torque is equilibrium restorative. This region is named positive synchronization region (PSR). Since the definition of the PSR boundaries have no dependence on modelling approximation, the PSR test conduces to reliable results. (C) 2008 Elsevier Ltd. All rights reserved.

Fatores socioeconômicos contextuais associados à condição bucal de adolescentes no Brasil

Many surveys are conducted comparing oral health conditions with individual variables, such as socioeconomic and demographic factors. However, in the same way that individuals differ among themselves, the groups also have their own characteristics and the effects of this differentiation must be researched. Brazil, despite being one of the major economic powers of the world and shows an improvement in the average value of its health indicators, is also one of the most unequal and remains among the countries with the greatest health inequities. The purpose of this study was to investigate the importance of social determinants on the contextual level oral health among Brazilian adolescents, population not much researched by the literature. The research was made using an ecological approach in order to identify possible inequalities between cities and capitals. Using data from SBBrasil 2010 it was evaluated less common outcomes (loss of first molar, dental care index and T-Health) which provide information on the degree of morbidity of caries and health level of dental tissues, in addition to analyze the related services. The association of these oral health indicators with socioeconomic factors such as income, employment, education and inequality, collected from Census 2010, was analyzed by simple and multiple linear regressions. The study included the 27 state capitals and four clusters representing the municipalities of the country. It was possible to see better access to services in locations with better income distribution. However, the strong association of contextual factors related to poverty, low levels of education and poor housing and jobs with poorer levels of oral health in adolescents seems to overshadow the effects of income inequalities on dental caries in the country. In some locations, particularly within the North and Northeast, whichever one keeps dentistry mutilating, whose effects are already noticeable in its adolescent population. Access to restorative services in Brazil remains limited and unequal. The results of this study highlight the inequities in oral health in the country and show the need of the inclusion of new perspectives on the traditional approach of Preventive Dentistry and education models in Dentistry. Tackling health inequalities in oral health in the country requires the cooperation of various actors involved in the process and the inclusion of oral health in the context of overall health. The social determinants approach, as well as evaluating the distribution of oral diseases in the country and its inclusion in the context of overall health, should guide the implementation of programs and oral health practices in order to contribute to the reduction of inequalities

Genotoxicity and cytotoxicity of glass ionomer cements on Chinese hamster ovary (CHO) cells

Glass ionomer cements are widely used in dentistry as restorative materials and adhesives for composite restorations. However, the results of genotoxicity studies using these materials are inconclusive in literature. The goal of this study was to examine the genotoxic and cytotoxic potential of three different glass ionomer cements available commercially (Ketac Cem, Ketac Molar and Vitrebond) by the single cell gel (comet) assay and trypan blue exclusion test, respectively. For this, such materials were exposed to Chinese hamster ovary (CHO) cells in vitro for 1 h at 37 degrees C. Data were assessed by Kruskall-Wallis nonparametric test. The results showed that the powder from Ketac Molar displayed genotoxicity only in the maximum concentration evaluated (100 mu g/mL). In the same way, the liquid from Vitrebond at 0.1% dilution caused an increase of DNA injury. Significant differences (P < 0.05) in cytotoxicity provoked by all powders tested of glass ionomer cements were observed for exposure at 1000 mu g/mL concentration. With respect to liquids of glass ionomer cements evaluated, the major toxic effect on cell viability was produced at 10%, beginning at the dilution of 0.5% for Vitrebond. Taken together, we conclude that some components of glass ionomer cements show both genotoxic and cytotoxic effects.