Bond strength of adhesive systems with different solvents to dry and wet dentin

Aim: This study evaluates bond strength between dentin and composite using adhesives with different solvents to dry and wet dentin. Materials and methods: Ninety bovine incisors were used; the vestibular surfaces were worn by the exposure of an area with a diameter of 4 mm of dentin. The specimens were divided into 6 groups, according to the type of adhesive used and hydratation stals: Group SB-wet: Single Bond 2 in wet dentin, Group SBdry: Single Bond 2 in dry dentin, Group SL-wet: Solobond M in wet dentin, Group SL-dry: Solobond M in dentin dry. Group XPwet: XP Bond in wet dentin, Group XP-dry: XP Bond in dentin dry. They were cut to obtain specimens in the shape of stick with 1 × 1 mm and subjected to microtensile test in universal testing machine with a cross speed of 1mm/min. The data were analyzed with ANOVA and Tukey's tests (5%). Results: ANOVA showed significant differences for surface treatment and interaction, but no difference was found for adhesive factor. The Tukey's test showed that the samples with wet dentin shown higher values of bond strength. Conclusion: The adhesive did not influence in the bond strength. The groups with wet dentin showed higher values of bond strength than groups with dry dentin.

Degree of conversion of polymer-matrix composite assessed by FTIR analysis

Aims and objectives: The behavior of polymer-matrix composite is dependent on the degree of conversion. The aim of this study was to evaluate the degree of conversion of two resin cements following storage at 37°C immediately, 24 and 48 hours, and 7 days after light-curing by FTIR analysis. Materials and methods: The specimens were made in a metallic mold and cured with blue LED with power density of 500 mW/cm2 for 30 seconds. The specimens were pulverized, pressed with KBr and analyzed with FTIR following storage times. Statistical analysis used: ANOVA (two-way) and Tukey's post hoc. Results: To the polymer-matrix composites between 24 and 48 hours does not show a significant increase (p > 0.05), however, the highest values were found after 7 days. Conclusion: The polymer-matrix composites used in this study showed similarity on the degree of conversion and increased of according to the time of storage.

Effects of cement-curing mode and light-curing unit on the bond durability of ceramic cemented to dentin

The aim of this study was to evaluate the effects of different light-curing units and resin cement curing types on the bond durability of a feldspathic ceramic bonded to dentin. The crowns of 40 human molars were sectioned, exposing the dentin. Forty ceramic blocks of VITA VM7 were produced according to the manufacturer's recommendations. The ceramic surface was etched with 10% hydrofluoric acid/60s and silanized. The dentin was treated with37% phosphoric acid/15s, and the adhesive was applied. The ceramic blocks were divided and cemented to dentin according to resin cement/RC curing type(dual-and photocured), light-curing unit (halogen light/QTH and LED), and storage conditions (dry and storage/150 days + 12,000 cycles/thermocycling). All blocks were stored in distilled water (37°C/24h) and sectioned (n = 10): G1-QTH + RC Photo, G2-QTH + RC Dual, G3-LED + RC Photo, G4-LED + RC Dual. Groups G5, G6, G7, and G8 were obtained exactly as G1 through G4, respectively, and then stored and thermocycled. Microtensile bond strength tests were performed (EMIC), and data were statistically analyzed by ANOVA and Tukey's test (5%). The bond strength values (MPa) were: G1-12.95 (6.40)ab; G2-12.02 (4.59)ab; G3-13.09 (5.62)ab; G4-15.96 (6.32)a; G5-6.22 (5.90)c; G6-9.48 (5.99)bc; G7-12.78 (11.30)ab; and G8-8.34 (5.98)bc. The same superscript letters indicate no significant differences. Different light-curing units affected the bond strength betweenceramic cemented to dentin when the photocured cement was used, and only after aging (LED>QTH). There was no difference between the effects of dual-and photo-cured resin-luting agents on the microtensile bond strength of the cement used in this study.

Compressive strength of dental composites photo-activated with different light tips

The aim of this study was to evaluate the compressive strength of microhybrid (Filtek™ Z250) and nanofilled (Filtek™ Supreme XT) composite resins photo-activated with two different light guide tips, fiber optic and polymer, coupled with one LED. The power density was 653 mW cm -2 when using the fiber optic light tip and 596 mW cm-2 with the polymer. After storage in distilled water at 37 ± 2 °C for seven days, the samples were subjected to mechanical testing of compressive strength in an EMIC universal mechanical testing machine with a load cell of 5 kN and speed of 0.5 mm min-1. The statistical analysis was performed using ANOVA with a confidence interval of 95% and Tamhane's test. The results showed that the mean values of compressive strength were not influenced by the different light tips (p > 0.05). However, a statistical difference was observed (p < 0.001) between the microhybrid composite resin photo-activated with the fiber optic light tip and the nanofilled composite resin. Based on these results, it can be concluded that microhybrid composite resin photo-activated with the fiber optic light tip showed better results than nanofilled, regardless of the tip used, and the type of the light tip did not influence the compressive strength of either composite. Thus, the presented results suggest that both the fiber optic and polymer light guide tips provide adequate compressive strength to be used to make restorations. However, the fiber optic light tip associated with microhybrid composite resin may be an interesting option for restorations mainly in posterior teeth. © 2013 Astro Ltd.

Are early and late rate of force development differently influenced by fast-velocity resistance training?

This study examined the effect of fast-velocity concentric isokinetic resistance training (FV) on the rate of force development (RFD) at early (<100 ms) and late phases (>100 ms) of rising muscle force. Nine men participated in a 6-week resistance training intervention for the lower body, and nine matched subjects participated as controls (CON). During concentric isokinetic (180°s-1) knee extension training, subjects were instructed to do each contraction 'as fast and forcefully as possible'. Maximal muscle strength (MVC) and RFD (0-10, 0-20, ..., 0-250 ms from the onset of contraction) were measured during maximal voluntary isometric contraction of the knee extensors (KE). There were no significant changes in MVC of KE in both groups after intervention (FV = 314·2 ± 101·1 versus 338·7 ± 88·0 N{bullet operator}m, P>0·05; CON = 293·3 ± 94·8 versus 280·0 ± 72·2 N{bullet operator}m, P>0·05). The RFD increased 39-71% at time intervals up to 90 ms from the onset of the contraction (P<0·05), whereas no change occurred at later time intervals. Similarly, relative RFD (i.e.%MVC{bullet operator}s-1) (RFDr) increased 33-56% at time intervals up to 70 ms from the onset of the contraction (P<0·05). It can be concluded that a short period of resistance training performed with concentric fast-velocity isokinetic muscle contractions is able to enhance RFD and RFDr obtained at the early phase of rising muscle force. © 2013 The Authors Clinical Physiology and Functional Imaging © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

Tiros de Movimento-Imagem: estudo de um processo artístico e pedagógico de Cristiane Paoli Quito

Pós-graduação em Artes - IA

Estudo clínico comparativo do aquecimento por eletroestimulação ou bicicleta estacionária como preparação ao alongamento muscular

Pós-graduação em Bases Gerais da Cirurgia - FMB

Influência do tipo de ponteira utilizada na fotoativação sobre o grau de conversão, dureza e resistência á compressão de resinas compostas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Experiência audiovisual e infância: em busca do que escapa ao primeiro olhar

Pós-graduação em Educação - IBRC

Benjamin torto na vida: o personagem gauche no romance de Chico Buarque

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Os desafios na construção da política de formação continuada dos orientadores pedagógicos da rede municipal de Presidente Prudente-SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A leitura na literatura infantil brasileira: a metodologia da personagem professor

Pós-graduação em Educação - FCT

Da feminilidade oitocentista

Pós-graduação em História - FCHS

A crise da economia colonial: as dimensões internas das práticas mercantilistas nos escritos de Brito e de Vilhena

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo sobre os efeitos de tensões residuais na vida em fadiga da liga de alumínio 6013-T6, em perfil tubular, submetidas a shot peening

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)