Nanotechnology in Dental Sciences: Moving Towards a Finer Way of Doing Dentistry

Nanotechnologies are predicted to revolutionize: (a) the control over materials properties at ultrafine scales; and (b) the sensitivity of tools and devices applied in various scientific and technological fields. In this short review, we argue that dentistry will be no exception to this trend. Here, we present a dynamic view of dental tissues, an adoption of which may lead to finer, more effective and minimally invasive reparation approaches. By doing so, we aim at providing insights into some of the breakthroughs relevant to understanding the genesis of dental tissues at the nanostructural level or generating dental materials with nanoscale critical boundaries. The lineage of the progress of dental science, including the projected path along the presumed nanotechnological direction of research and clinical application is mentioned too. We conclude by claiming that dentistry should follow the trend of probing matter at nanoscale that currently dominates both materials and biological sciences in order to improve on the research strategies and clinical techniques that have traditionally rested on mechanistic assumptions

O poder de influência das redes sociais no consumo de conteúdos da Netflix em Portugal

Dissertação de mestrado apresentada à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Publicidade e Marketing.No mundo digital em que vivemos, as redes sociais podem ser poderosos acessórios na construção de ideias ou opiniões sobre uma determinada matéria. A presente investigação procurou averiguar a relação entre a utilização das redes sociais e o consumo de conteúdos da Netflix no panorama português. Deste modo, a questão de partida que se colocou foi: “A interação entre utilizadores nas redes sociais pode influenciar o consumo de séries e/ou filmes da Netflix em Portugal?”. Os principais objetivos deste trabalho consistem em entender a relação da população com as redes sociais, se estas conseguem influenciar as escolhas dos consumidores relativamente a produtos ou serviços, perceber a relação dos indivíduos com a Netflix, caracterizar o utilizador desta plataforma e, por último, fazer a relação entre as redes sociais e a Netflix. O método utilizado foi o inquérito por questionário online, dividido em quatro grupos de questões: i) redes sociais, ii) Netflix, iii) redes sociais e Netflix e iv) características sociodemográficas. O questionário foi partilhado através das redes sociais, onde obteve uma amostra de 254 respostas. Os principais resultados reunidos nesta investigação demonstram que as redes sociais conseguem ser elementos influenciadores entre os inquiridos no momento de escolherem uma série ou um filme da Netflix.ABSTRACT: In the digital world where we live, social networks can be powerful accessories in the construction of ideas or opinions on a particular subject. The present investigation explores the relation between the use of social networks and the content consumption from Netflix in Portugal. Thus, the starting question was: “Can the interaction between users on social networks influence the consumption of Netflix TV shows or movies in Portugal?”. The main goals of this work are to understand the population’s relation with social networks, whether social networks can influence user’s choices regarding products or services, understand people’s relation with Netflix, characterize the platform user and, finally, to establish the relationship between social networks and Netflix. The method used was an online questionnaire survey, divided into four groups of questions: i) social networks, ii) Netflix, iii) social networks and Netflix and iv) sociodemographic characteristics. The survey was shared through social networks, where it obtained a sample of 254 responses. The main results gathered in this investigation show that social networks can be influential elements among the respondents when choosing a Netflix series or movie.N/

Mulheres do século XX : memórias de trajetórias de vida, suas representaçoes (1936-2000)

Orientadora: Etelvina Maria de Castro TrindadeAutor não autorizou a divulgação do arquivo digitalTese (doutorado) - Universidade Federal do Paraná, Setor de Ciencias Humanas, Letras e Artes, Programa de Pós-Graduaçao em História. Defesa: Curitiba, 2004Inclui bibliografiaÁrea de concentração :Resumo: O objetivo deste trabalho foi investigar como mulheres, que viveram o século XX - como adultas -, representam suas experiências e como, durante seus depoimentos, o filtro da memória mostra o arraigamento ou metamorfoses dos modelos que cada época ou sociedade veicula e, assim, permitem a construção de identidades. Para tanto foi feita uma pesquisa qualitativa, com metodologia da história oral, usando entrevistas semi-abertas, com 18 depoentes, nascidas entre 1920 a 1980. Os critérios de inclusão na amostra foram: a idade (variando entre 83 e 23 anos na época da entrevista) e a diversidade de ocupação ou profissão (18 diferentes ocupações). Como categorias de análise, tomou-se a memória e o gênero, tendo como pressuposto que as identidades humanas são construídas, ao longo da vida, pela interpretação que os valores do grupo, assimilados por seus indivíduos, atribuem às experiências vividas e, que, estas sofrem mutação quando expostas ao filtro da memória. A amostra foi dividida em sub-grupos geracionais, cada qual com seis depoentes: a primeira geração (1936/1950); a segunda (1960/1970) e, a terceira (1980/2000). Os dados permitiram construir quatro capítulos. Três deles correspondentes à análise de cada grupo e, estes iniciaram pelo relato de vida de uma das participantes, cuja trajetória de vida servia como fio condutor da análise dos itens selecionados também do relato das outras entrevistadas. As escolhidas para representarem seus grupos foram aquelas que reuniram características mais emblemáticas de sua geração, no caso: Branca Raquel e Áurea, respectivamente. A hipóteses iniciais foram confirmadas: há mudanças nas representações sociais, intra e entre gerações, porém as alterações são graduais e se percebem, ainda, permanências de valores. Palavras-chave: gênero; memória; representações sociais; história oral e identidade.Abstract: This work aimed to investigate how women that lived the 20th century - as grown-upsrepresented their experiences and, during their statements how their memory strainer shows the deepened of the standards or the changes that each time or society displays and, in this way how they lead the identities' built. So, it was conducted a qualitative research, oral history, by partially-opened interviews of 18 participants who were born between the 20's and the 80's. The sample's inclusion criteria was: age (varying from 83 and 23 years old by the time they were interviewed), and the professional diversity (18 different occupations). Were taken as analysis categories memory and gender, having as a fundamental principle that the human identities are built during the life time through the interpretation that the group values, as they are internalized by the individuals, assign to the experiences, and also that these experiences change when exposed to the memory strainer. The sample was divided into generational subgroups, each one with six respondents: first generation, 1936/1950; the second, 1960/1970 and, the third, 1980/2000. The data allowed building four chapters. Three correspondent to the analysis of each group, and these started by one participant's life speech. This life speech's path served as an analysis string of the selected items of the others respondents. The ones chosen to represent their groups were those who accomplished the characteristics more emblematic of their generation. The first hypothesis was confirmed: there are changes in the social representations, into and inter generations, but the changes are gradative and, still can be perceived values permanence. Key words: gender, memory, oral history, social representations and Sociability

A legislação em saúde mental no Brasil (1841-2001) : trajeto da consolidação de um modelo de atenção

Orientador: Prof. Dr. Adriano Furtado HolandaDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Humanas, Programa de Pós-Graduação em Psicologia. Defesa: Curitiba, 03/06/2014Inclui referênciasResumo: Este trabalho objetiva discutir a legislação na área de saúde mental no Brasil, entre 1841 e 2001, período que formaliza o modelo de atenção de tipo asilar, centrado no Hospital Psiquiátrico. O texto se divide entre as primeiras legislações, o início do século XX, a fase de consolidação e a reorganização da forma de atenção, a partir da legislação que abrange o território nacional. São selecionadas regulamentações que apresentem pontos marcantes da política oficial de saúde mental, como definições administrativas, organização de serviços e do modelo assistencial. O recorte metodológico se dá por conta da possibilidade de verificação destes documentos, acessíveis pelos sítios oficiais das instituições públicas estatais. A literatura aponta dois modelos significativamente diferentes – o modelo asilar e o modelo psicossocial – sendo que se busca o fundamento legislativo do primeiro modelo, para compreender a passagem para o modelo psicossocial, tomando como marco, a aprovação da lei 10216/2001Abstract: This work discusses the brazilian legislation about mental health between 1841 and 1988, a period that represents the moment of formalization of a model of care centered on asylum, the Psychiatric Hospital. The text is divided in four points: the first laws, the early twentieth century, a period of consolidation and reorganization of the manners of attention from the legislation covering the national territory. There are selected regulations that present striking points of official mental health policy, and administrative settings, coordination of services and care model. This methodological approach is given because of the possibility of verifying these documents, accessible by public official websites of state institutions. The literature points to two significantly different models – the asylum model and the psychosocial model – with the search for the legislative basis of the first model to understand the passage to the psychosocial model, using as a frame, the approval of law 10216/2001

Mechanical heterogeneity of dentin at different length scales as determined by AFM phase contrast

In this study we sought to gain insights of the structural and mechanical heterogeneity of dentin at different length scales. We compared four distinct demineralization protocols with respect to their ability to expose the periodic pattern of dentin collagen. Additionally, we analyzed the phase contrast resulting from AFM images obtained in tapping mode to interrogate the viscoelastic behavior and surface adhesion properties of peritubular and intertubular dentin, and partially demineralized dentin collagen fibrils, particularly with respect to their gap and overlap regions. Results demonstrated that all demineralization protocols exposed the gap and overlap zones of dentin collagen fibrils. Phase contrast analyses suggested that the intertubular dentin, where the organic matrix is concentrated, generated a higher phase contrast due a higher contribution of energy dissipation (damping) than the highly mineralized peritubular region. At increasing amplitudes, viscoelasticity appeared to play a more significant contribution to the phase contrast of the images of collagen fibrils. The overlap region yielded a greater phase contrast than the more elastic gap zones. In summary, our results contribute to the perspective that, at different length scales, dentin is constituted of structural features that retain heterogeneous mechanical properties contributing to overall mechanical performance of the tissue. Furthermore, the interpretation of phase contrast from images generated with AFM tapping mode appears to be an effective tool to gain an improved understanding of the structure and property relationship of biological tissues and biomaterials at the micro- and nano-scale

Opportunities and challenges to engineer 3D models of tumor-adaptive immune interactions

Augmenting adaptive immunity is a critical goal for developing next-generation cancer therapies. T and B cells infiltrating the tumor dramatically influence cancer progression through complex interactions with the local microenvironment. Cancer cells evade and limit these immune responses by hijacking normal immunologic pathways. Current experimental models using conventional primary cells, cell lines, or animals have limitations for studying cancer-immune interactions directly relevant to human biology and clinical translation. Therefore, engineering methods to emulate such interplay at local and systemic levels are crucial to expedite the development of better therapies and diagnostic tools. In this review, we discuss the challenges, recent advances, and future directions toward engineering the tumor-immune microenvironment (TME), including key elements of adaptive immunity. We first offer an overview of the recent research that has advanced our understanding of the role of the adaptive immune system in the tumor microenvironment. Next, we discuss recent developments in 3D in-vitro models and engineering approaches that have been used to study the interaction of cancer and stromal cells with B and T lymphocytes. We summarize recent advancement in 3D bioengineering and discuss the need for 3D tumor models that better incorporate elements of the complex interplay of adaptive immunity and the tumor microenvironment. Finally, we provide a perspective on current challenges and future directions for modeling cancer-immune interactions aimed at identifying new biological targets for diagnostics and therapeutics

Remineralization of demineralized dentin using a dual analog system.

ObjectiveImproved methods are needed to remineralize dentin caries in order to promote conservation of dentin tissue and minimize the surgical interventions that are currently required for clinical treatment. Here, we test the hypothesis that bulk substrates can be effectively mineralized via a dual analog system proposed by others, using a tripolyphosphate (TPP) "templating analog" and a poly(acrylic acid) (PAA) or poly(aspartic acid) (pAsp) "sequestration analog," the latter of which generates the polymer-induced liquid-precursor (PILP) mineralization process studied in our laboratory.Material & methodsDemineralized human dentin slices were remineralized with and without pre-treatment with TPP, using either PAA or pAsp as the PILP process-directing agent. A control experiment with no polymer present was used for comparison.ResultsNo mineralization was observed in any of the PAA groups. In both the pAsp and no polymer groups, TPP inhibited mineralization on the surfaces of the specimens but promoted mineralization within the interiors. Pre-treatment with TPP enhanced overall mineralization of the pAsp group. However, when analysed via TEM, regions with little mineral were still present.ConclusionPoly(acrylic acid) was unable to remineralize demineralized dentin slices under the conditions employed, even when pre-treated with TPP. However, pre-treatment with TPP enhanced overall mineralization of specimens that were PILP-remineralized using pAsp

A zinc oxide-modified hydroxyapatite-based cement facilitated new crystalline-stoichiometric and amorphous apatite precipitation on dentine.

Aim: To evaluate the remineralization ability of two dentin canal sealer cements. Methodology: Dentin surfaces were subjected to: i) 37% phosphoric acid (PA) or ii) 0.5 M ethylenediaminetetraacetic acid (EDTA) conditioning prior to the application of two experimental hydroxyapatite-based cements, containing sodium hydroxide (calcypatite) or zinc oxide (oxipatite), respectively. Samples were stored in simulated body fluid during 24 h or 21 d. Remineralization of the dentin surfaces were studied by Raman spectroscopy, mapping with K-means cluster and hierarchical cluster analysis were done. Nano-roughness and collagen fibrils width measurements were performed by means of an atomic force microscopy. Results: PA+oxipatite promoted both the highest dentin mineralization and crystallographic maturity at the dentin surface. Non-crystalline amorphous-like apatites were also formed. Dentin treated with PA+calcypatite attained the roughest surface with minimal fibril width. Crosslinking of collagen only raised in the group PA+oxipatite, after 21 d. The maximum relative mineral concentration and structure of collagen referred to amide I and ratio amide III/AGEs was achieved after using PA+calcypatite at 21 d time point. EDTA produced a lower stoichiometric hydroxyapatite with decreased maturity, at the expense of the carbonate band widening, though it favored the nucleation of carbonated calcium phosphate. Conclusions: Surfaces treated with PA+oxipatite attained the highest dentin remineralization with both crystalline-stoichiometric and amorphous apatites, at long term. EDTA conditioning facilitated amorphous-bulk mineral precipitation. This amorphization, more intense after using oxipatite, provided an ion-rich environment favoring in situ dentin remineralization.This work was supported by the Ministry of Economy and Competitiveness (MINECO) [Project MAT2014-52036-P] and European Regional Development Fund (FEDER)

Functional Remineralization of Dentin Lesions Using Polymer-Induced Liquid-Precursor Process

It was hypothesized that applying the polymer-induced liquid-precursor (PILP) system to artificial lesions would result in time-dependent functional remineralization of carious dentin lesions that restores the mechanical properties of demineralized dentin matrix. 140 µm deep artificial caries lesions were remineralized via the PILP process for 7–28 days at 37°C to determine temporal remineralization characteristics. Poly-L-aspartic acid (27 KDa) was used as the polymeric process-directing agent and was added to the remineralization solution at a calcium-to-phosphate ratio of 2.14 (mol/mol). Nanomechanical properties of hydrated artificial lesions had a low reduced elastic modulus (ER = 0.2 GPa) region extending about 70 μm into the lesion, with a sloped region to about 140 μm where values reached normal dentin (18–20 GPa). After 7 days specimens recovered mechanical properties in the sloped region by 51% compared to the artificial lesion. Between 7–14 days, recovery of the outer portion of the lesion continued to a level of about 10 GPa with 74% improvement. 28 days of PILP mineralization resulted in 91% improvement of ER compared to the artificial lesion. These differences were statistically significant as determined from change-point diagrams. Mineral profiles determined by micro x-ray computed tomography were shallower than those determined by nanoindentation, and showed similar changes over time, but full mineral recovery occurred after 14 days in both the outer and sloped portions of the lesion. Scanning electron microscopy and energy dispersive x-ray analysis showed similar morphologies that were distinct from normal dentin with a clear line of demarcation between the outer and sloped portions of the lesion. Transmission electron microscopy and selected area electron diffraction showed that the starting lesions contained some residual mineral in the outer portions, which exhibited poor crystallinity. During remineralization, intrafibrillar mineral increased and crystallinity improved with intrafibrillar mineral exhibiting the orientation found in normal dentin or bone

Zinc-modified nanopolymers improve the quality of resin-dentin bonded interfaces

Introduction: Demineralized collagen fibers at the hybrid layer are susceptible to degradation. Remineralization may aid to improve bond longevity. Objectives: The aim of the present study was to infiltrate zinc and calcium-loaded polymeric nanoparticles into demineralized dentin to facilitate hybrid layer remineralization. Materials and methods: Zinc or calcium-loaded polymeric nanoparticles were infiltrated into etched dentin, and Single Bond Adhesive was applied. Bond strength was tested after 24 h and 6 months storage. Nanomechanical properties, dyeassisted confocal laser microscopy, and Masson’s trichrome staining evaluation were performed to assess for the hybrid layer morphology, permeability, and remineralization ability after 24 h and 3 months. Data were analyzed by ANOVA and Student–Newman–Keuls multiple comparisons tests (p < 0.05). Results: Immediate bond strength was not affected by nanoparticles infiltration (25 to 30 MPa), while after 6 months, bond strengths were maintained (22 to 24 MPa). After 3 months, permeability occurred only in specimens in which nanoparticles were not infiltrated. Dentin remineralization, at the bottom of the hybrid layer, was observed in all groups. After microscopy analysis, zinc-loaded nanoparticles were shown to facilitate calcium deposition throughout the entire hybrid layer. Young’s modulus at the hybrid layer increased from 2.09 to 3.25 GPa after 3 months, in specimens with zinc nanoparticles; meanwhile, these values were reduced from 1.66 to 0.49 GPa, in the control group. Conclusion: Infiltration of polymeric nanoparticles into demineralized dentin increased long-term bond strengths. Zinc-loaded nanoparticles facilitate dentin remineralization within the complete resin–dentin interface. Clinical relevance: Resin–dentin bond longevity and dentin remineralization at the hybrid layer were facilitated by zincloaded nanoparticles.This work was supported by a grant, MINECO/FEDER MAT2014-52036-P