Color stability of composites: effect of immersion media.

Coloring in drinks decreases the color stability of composite restorations, reducing their longevity. The purpose of this in vitro study was to evaluate the effect of immersion media on color stability of seven different composite resins (Solidex - Shofu, Resilab-Wilcos, Signum - Heraeus, Epricord - Tokuyama, Adoro - Ivoclar Vivadent, Admira - Voco and Sinfony - 3MESPE). Seven resin-based composite specimens were prepared using a cylindrical teflon mold 2 mm thick and 10 mm in diameter Fifteen specimens of each resin were light-cured according to manufacturers' instructions and randomized into 3 groups (n= 5) according to immersion media: coffee, cola beverage and water A digital spectrophotometer Easy Shade (VITA) was used to evaluate the color changes at baseline and 7 days after immersion in each solution. Specimens were stored in the different staining media for 24 h/day during one week. The color differences were analyzed by two-way ANOVA and Tukey 's test (p< 0.05). Color change was observed after one week of immersion and there were statistical differences in staining, composite and interaction factors. The least staining was observed in Admira (deltaE= 3.934+/-0.814) and Resilab (deltaE= 3.993+/-0.735), followed by Adoro (deltaE= 4.044+/-1.001), Epri-cord (deltaE= 4.049+/-1.234), Signum (deltaE= 4.260+/-1.785), Solidex (deltaE=5,122+/-0.534) and Sinfony (deltaE=5.126+/-0.838). All of the composites tested except Adoro were susceptible to staining by substances present in coffee and cola, when stored in beverage for seven days. The lowest deltaE means were obtained with Admira.

Influência do volume do preparo oclusal para inlays e do material restaurador na distribuição de tensão e resistência à fratura de pré-molares

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A formação do Professor de Línguas de uma Perspectiva Sociocultural

With the development of cognition studies and the awareness that teachers’ previous experiences, knowledge acquired in language teacher education programs and classroom experiences in different contexts shape the ways teachers think and construct their teaching practices, teacher education programs start to understand, from a sociocultural perspective, teachers’ learning as a dialogic process of knowledge co-construction, which is situated and emerges from practices and sociocultural contexts. Considering the relevance of this new perception, this article aims at presenting such theoretical perspective as well as its contributions to language teacher education research and teaching.

Análise das colocações especializadas da área de sensoriamento remoto sob a perspectiva da fraseologia

The aim of this research is to build and analyze a parallel corpus in the field of remote sensing in order to identify, according to its frequency, specialized collocations in English and then search for their equivalents in Portuguese. The research is based on the interdisciplinary approach of Corpus-Based Translation Studies (BAKER, 1995; CAMARGO, 2007), Corpus Linguistics (BERBER SARDINHA, 2004; TOGNINI-BONELLI, 2001), Phraseology (ORENHA-OTTAIANO, 2009; PAVEL, 1993), and some principles of Terminology (BARROS, 2004). For manipulating the corpora, the program WordSmith Tools (SCOTT, 2012) version 6.0 is used. To support this study, two comparable corpora in English and Portuguese were also built from articles published in both national and international journals in remote sensing. The results show that the collocations in Portuguese seem to be still in the process of conventionalization, as the translators made use of greater variation in their translational options, which can be a way to make the text clearer for the reader.

Crenças, pressupostos e conhecimentos de professores em serviço sobre língua(gem) em um curso de formação continuada

O cenário atual de globalização e comunicação intercultural traz impacto significativo para a maneira como entendemos a relação entre língua e sociedade. Gera, também, para o ensino de línguas, a necessidade de o professor compreender suas crenças, pressupostos e conhecimentos (WOODS, 1996) em relação à língua que ensina, uma vez que ele é um importante agente na orquestração da interação de várias histórias de vida e horizontes de entendimento por meio de sua prática pedagógica. Neste artigo, apresentamos e discutimos os resultados de duas pesquisas de doutorado (SALOMÃO, 2012; MENEGHINI, 2013), conduzidas em um mesmo contexto de um curso híbrido (presencial/virtual) de formação continuada, em relação às crenças dos professores sobre as variedades geolinguísticas do espanhol. Ponderamos que a questão da escolha por uma variedade está muitas vezes relacionada às concepções estruturais de língua, assim como está imbricada por uma tessitura de fatores que demonstram falta de consciência das vozes das quais os professores se apropriam para justificar suas opções teórico-metodológicas. O desafio que se coloca para a formação de professores, então, nos parece ser o de auxiliá-los no desenvolvimento de consciência crítica, promovida pela reflexão sobre suas crenças sobre língua(gem), a partir de experiências que possam levá-los a (re)conhecer suas escolhas por determinada variedade linguística. Palavras-chave: Crenças de professores de línguas. Variedades linguísticas. Reflexão.

Paixão, mito e formas de vida em textos publicitários

The passion, understood by Aristotle, as a contingency which causes a change in the essence of the subject, was object of research of the Greek philosopher as rhetorical strategy used by the speaker to touch its listeners. The greimasian semiotics, enlarging the concept of Aristotle’s passion, understands it as the soul states of a subject that can be gathered form the analysis of a text. Reflections towards the passion discursivization and its persuasion effects in advertisements lead us to establish the relationships between passion, myth and ways of life.

Vozes de professores: indícios de/para cursos de formação

In this article we analyze discourses of teachers on the linguistic practices of their students and discourses of future teachers. We consider studies of Bakhtin on dialogism and ideology in the production of meanings. Results indicate the following conclusions: the student in the analyzed discourses is a bad speaker, a bad writer, a bad reader, the great villain of language and reading in school is the advent of new technologies and languages which introduce new practices that have not been accepted by the interviewees. In this discourses, we can notice ways that can be taken into consideration in new teacher’s formation courses.

Um espelho esmaecido: o reino visigodo de Toledo, cristianismo e monarquia

This paper aims to present some characteristics of Hispania in Late Antiquity and Early Middle Ages (4th-8th centuries). Search through a brief analysis of the relationship between Christianity and the Catholic Monarchy stood raise some issues and questions. We understand that Christianity has played and plays a significant role in the historical development of the Iberian countries. But in its installation and attempt to consolidation as hegemonic religion in the peninsula, faced several challenges. His alliance with the monarchy stood represented one of the ways to make stronger its dominance. In turn, the Monarchy, preserving its characteristic elective associated strongly with Christianity, giving him a theocratic character trying to raise the sovereign above the fray aristocratic, without much success. Thus, our text points to some of the paths followed by these two elements, Christianity and Monarchy at the time of the Kingdom of Toledo, proposing more reflections and ways that effectively covering them. We hope to have achieved it.

Can Application of Universal Primers Alone Be a Substitute for Airborne-Particle Abrasion to Improve Adhesion of Resin Cement to Zirconia?

Purpose: To determine whether universal primers alone can deliver similar levels of adhesion of resin cement to zirconia ceramic when compared to their application in conjunction with airborne-particle abrasion.Materials and Methods: Sintered zirconia blocks (N = 160) (Lava, 3M ESPE), (5.25 x 5.25 x 3 mm(3)) were embedded in acrylic resin, polished, and randomly distributed into 16 groups (n = 10 per group), according to the factors "universal primer" (8 levels) and "air-particle abrasion" (2 levels): 1. ctr: control, without application of a universal primer; 2. AP: Alloy Primer; 3. MP: Monobond Plus; 4. MZP: Metal Zirconia Primer; 5. MZ: MZ Primer; 6. Sg: Signum Zirconia Bond; 7. SbU: Singlebond Universal; 8. ZP: Z Prime Plus. The universal primers were also used after air abrasion (A) of zirconia to form the following 8 groups: Ctr-A, AP-A, MP-A, MZP-A, MZ-A, Sg-A, SbU-A, and ZP-A. After ultrasonic cleaning, air abrasion was performed using Al2O3 particles (110 mu m, 2.5 bar, 20 s at 10 mm) in a chairside air-abrasion device. After ultrasonic cleaning again, universal primers were applied according to each manufacturer's recommendation. The resin cement (RelyX ARC, 3M ESPE) was built up incrementally and photo-polymerized on the zirconia surface using a silicone mold (empty set = 3.5, height = 3 mm). All specimens were stored in distilled water (60 days at 37 degrees C) and then subjected to shear bond strength testing (SBS) in a universal testing machine (1 mm/min). On a separate set of zirconia specimens, contact angle measurements were made using the sessile drop technique with a goniometer after the application of universal primers on control and air-abraded zirconia surfaces. Data (MPa) were analyzed using one-way ANOVA, Tukey's test, and Student's t-test (alpha = 0.05).Results: When universal primers were used alone, SbU presented significantly higher mean SBS (19.5 +/- 5.8) that did the other primers (0 to 9.9 +/- 6.6) (p = 0.001). When air abraded, the groups AP-A (14.1 +/- 6.1), MP-A (15.9 +/- 5.4), ZP-A (16.9 +/- 7.3), SG-A (19.1 +/- 2.1), SbU-A (12 +/- 1.5) showed significant differences (p = 0.03). Adhesive performance of all universal primers was enhanced after air abrasion, with the exception of the SbU and MZ primers. After air abrasion, contact angle measurements were lower for the each primer (without air abrasion: 28.9 to 83.9; with air abrasion: 27.1 to 63.0), except for MZP.Conclusion: Air abrasion with 110 mu m Al2O3 followed by universal primer application increased the bond strength of tested resin cement to zirconia, with the exception of SbU and MZ.

Influence of Nd:YAG or Er:YAG laser surface treatment on microtensile bond strength of indirect resin composites to resin cement. Lasers surface treatment of indirect resin composites

This study evaluated the influence of the surface pretreatment of indirect resin composite (Signum, Admira Lab and Sinfony) on the microtensile bond strength of a resin cement. Sixty samples made of each brand were divided into 6 groups, according to surface treatment: (1) control; (2) controlled-air abrasion with Al2O3; (3) Er:YAG Laser 200 mJ, 10 Hz, for 10s; (4) Er: YAG Laser 300 mJ, 10 Hz, for 10 s; (5) Nd:YAG 80 mJ, S15Hz for 1 min; (6) Nd:YAG 120mJ, 15 Hz for 1 min. After treatments, all the groups received an application of 37% phosphoric acid and adhesive. The pair of blocks of the same brand were cemented to each other with dual resin cement. The blocks were sectioned to obtain resin-resin sticks (1 x1 mm) and analyzed by microtensile bond testing. The bond strength values were statistically different, irrespective of the surface treatment performed, with highest values for Sinfony (43.81 MPa) and lowest values for Signum (32.33 MPA). The groups treated with the Nd:YAG laser showed the lowest bond strength values and power did not interfere in the results, both for Nd:YAG laser and Er:YAG. Controlled-air abrasion with Al203 is an efficient surface treatment method and the use of the Nd:YAG and Er:YAG lasers reduced bond strength, irrespective of the intensity of energy used.

Abrasion resistance of direct and indirect resins as a function of a sealant veneer

Abrasive wear is one of the most common type of wear that not only affect teeth, as also dental restorations. Thus to investigate one of the etiological factors as tooth brushing procedure is clinical relevant in order to select the best material combination that may prevent damage of resin dental restoration's abrasion. This study evaluated the influence of tooth brushing on mass loss and surface roughness of direct Venus (Vs) and indirect Signum (Sg) resin composites, with and without a surface sealant, Fortify (F). Twenty-four specimens were prepared with each resin composite, using their proprietary curing units, according to manufacturer's instructions. All the specimens were polished and ultrasonically cleaned in distilled water for 5 minutes. Half of the specimens of each resin (n = 12) were covered with F (Vs F and Sg F ), except for the control (C) specimens (Vs C and Sg C ), which were not sealed. Mass loss (ML) as well as surface roughness (Ra ) was measured for all the specimens. Then, the specimens were subjected to toothbrush-dentifrice abrasion, using a testing machine for 67.000 brushing strokes, in an abrasive slurry. After brushing simulation, the specimens were removed from the holder, rinsed thoroughly and blot dried with soft absorbent paper. The abrasion of the material was quantitatively determined with final measurements of ML and surface roughness, using the method described above. ML data were analyzed by two-way analysis of variance (ANOVA) and the analysis indicated that resin composites were not statistically different; however, the specimens sealed with F showed higher ML. Ra mean values of the groups Vs F and Sg F significantly increased. Tooth brushing affects mainly the roughness of the direct and indirect resin composites veneered with a sealant.