Evaluation of bond strength of dual resin cements to CAD/CAM-created lithium disilicate ceramic.

BACKGROUND: The objective was to examine the microshear bond strength values of different dual resin cements to computer-aided design (CAD)/computer-aided manufacturing (CAM)-created ceramics containing lithium disilicate, which underwent different surface treatments. METHODS: Two dual resin cements (RelyX ARC and RelyX Ultimate) and three surface treatments of lithium disilicate ceramic blocks (Ceramic Primer (CP; containing silane) plus Adper Scotchbond Multipurpose (ASM) adhesive; CP plus Single Bond Universal (SBU) adhesive; and SBU adhesive alone) were tested. The SBU adhesive includes silane in its formulation. Each sample underwent a microshear test and bond strength values were subjected to analysis of variance (ANOVA) followed by Tukey's test (α=0.05). Fracture patterns were also observed with light microscopy. RESULTS: RelyX ARC treated with CP+ASM or CP+SBU presented resistance values that were significantly higher than the same treatments for RelyX Ultimate. Conversely, for the blocks treated with SBU alone, the mean resistance value for RelyX Ultimate was higher than that of RelyX ARC. Regarding the different types of treatment for each resin, the mean resistance value of RelyX ARC treated with CP+ASM was significantly highest, followed by treatment with CP+SBU and SBU treatment alone. Meanwhile, RelyX Ultimate treated with CP+ASM or CP+SBU presented resistance values that were significantly higher than SBU treatment alone. In all of the groups, an adhesive fracture pattern was predominantly observed. CONCLUSIONS: The present results indicate that silanization is important for ASM and SBU adhesives to be effective.

Description and characterization of an alternative technique for temporary crown cementation with calcium hydroxide cement.

The purpose of this study was to describe and characterize (using the tensile test) an alternative handling technique for calcium hydroxide cement in temporary crown cementation. In the group treated with the conventional technique (n=10), the base and catalyst pastes of a calcium hydroxide cement (Dycal) were dispensed at a 1:1 ratio and mixed. The cement was then applied to the internal cervical surfaces of the provisional restoration, and the restoration was placed on the prepared tooth and kept in place with digital pressure. In the group treated with the alternative technique (n=10), the base paste of the calcium hydroxide cement (Dycal) was placed on the tooth and the catalyst paste was inserted into the temporary crown.The provisional prosthesis was placed on the tooth and kept in place with digital pressure. Tensile values were evaluated and compared between groups using Student's t test with a 5% level of significance (α = 0.05). Use of this alternative technique resulted in significantly lower tensile strength compared to the conventional technique (0.58 ± 0.12 vs. 1.08 ± 0.13 MPa; p<0.001). The technique presented here (alternative) could avoid the undesired removal of cemented cast posts or cores at the time of provisional prosthesis removal and ensures the cementation of extensive provisional prostheses with calcium hydroxide cement.

O objetivo deste estudo foi descrever e caracterizar (utilizando o ensaio de tração) uma técnica alternativa de manuseio para o cimento de hidróxido de cálcio na cimentação de coroa temporária. No grupo tratado com a técnica convencional (n=10), as pastas base e catalisadora de um cimento de hidróxido de cálcio (Dycal) foram dispensadas na proporção de 1:1 e misturadas. O cimento foi entao aplicado as superficies cervicais internas da restauração provisória, e a restauração foi colocada sobre o dente preparado e mantido no local com pressao digital. No grupo tratado com a técnica alternativa (n=10), a pasta base do cimento de hidróxido de cálcio (Dycal) foi colocada no dente e a pasta catalítica foi inserida na coroa provisória. A prótese provisória foi colocada sobre o dente e mantida no local com pressao digital. Os valores de tração foram avaliados comparados entre os grupos pelo teste t de Student, com nivel de significancia de 5% (α = 0,05). O uso desta técnica alternativa resultou em resistência à tração significativamente menor em comparação com a técnica convencional (0,58 ± 0,12 vs. 1,08 ± 0,13 MPa; p <0,001). A técnica aqui apresentada (alternativa) poderia evitar a remoção indesejada de pinos ou núcleos fundidos no momento da remoção da prótese provisória e garantir a cimentação de próteses provisórias extensas com cimento de hidróxido de cálcio.

Description and characterization of an alternative technique for temporary crown cementation with calcium hydroxide cement

The purpose of this study was to describe and characterize (using the tensile test) an alternative handling technique for calcium hydroxide cement in temporary crown cementation. In the group treated with the conventional technique (n=10), the base and catalyst pastes of a calcium hydroxide cement (Dycal) were dispensed at a 1:1 ratio and mixed. The cement was then applied to the internal cervical surfaces of the provisional restoration, and the restoration was placed on the prepared tooth and kept in place with digital pressure. In the group treated with the alternative technique (n=10), the base paste of the calcium hydroxide cement (Dycal) was placed on the tooth and the catalyst paste was inserted into the temporary crown. The provisional prosthesis was placed on the tooth and kept in place with digital pressure. Tensile values were evaluated and compared between groups using Student's t test with a 5% level of significance (α = 0.05). Use of this alternative technique resulted in significantly lower tensile strength compared to the conventional technique (0.58 ± 0.12 vs. 1.08 ± 0.13 MPa; p<0.001). The technique presented here (alternative) could avoid the undesired removal of cemented cast posts or cores at the time of provisional prosthesis removal and ensures the cementation of extensive provisional prostheses with calcium hydroxide cement (AU)

O objetivo deste estudo foi descrever e caracterizar (utilizando o ensaio de tração) uma técnica alternativa de manuseio para o cimento de hidróxido de cálcio na cimentação de coroa temporária. No grupo tratado com a técnica convencional (n=10), as pastas base e catalisadora de um cimento de hidróxido de cálcio (Dycal) foram dispensadas na proporção de 1:1 e misturadas. O cimento foi então aplicado às superfícies cervicais internas da restauração provisória, e a restauração foi colocada sobre o dente preparado e mantido no local com pressão digital. No grupo tratado com a técnica alternativa (n=10), a pasta base do cimento de hidróxido de cálcio (Dycal) foi colocada no dente e a pasta catalítica foi inserida na coroa provisória. A prótese provisória foi colocada sobre o dente e mantida no local com pressão digital. Os valores de tração foram avaliados comparados entre os grupos pelo teste t de Student, com nível de significância de 5% (α = 0,05). O uso desta técnica alternativa resultou em resistência à tração significativamente menor em comparação com a técnica convencional (0,58 ± 0,12 vs. 1,08 ± 0,13 MPa; p <0,001). A técnica aqui apresentada (alternativa) poderia evitar a remoção indesejada de pinos ou núcleos fundidos no momento da remoção da prótese provisória e garantir a cimentação de próteses provisórias extensas com cimento de hidróxido de cálcio (AU)

Análise comparativa de equações de predição para estimar o consumo máximo de oxigênio e aplicabilidade de equações a partir do incremental Shuttle Walk Test em mulheres jovens / Comparative analysis of prediction equations for estimating maximum oxygen consumption and applicability of equations from the shuttle walk test incremental in young women

A avaliação da aptidão cardiorrespiratória é realizada através do consumo máximo de oxigênio (VO2máx), que é a medida mais difundida da aptidão aeróbia em indivíduos jovens e o melhor parâmetro fisiológico para avaliar a capacidade funcional do sistema cardiorrespiratório, geralmente mensurados, de forma direta, através da ergoespirometria. A fim de facilitar a avaliação do VO2máx, utilizam-se equações de predição originadas a partir de características gerais dos indivíduos, ou a partir do desempenho em testes de campo, como o "Incremental Shuttle Walk Test" (ISWT). A partir do desempenho no teste, utilizam-se equações de predição de VO2máx para estimar a aptidão aeróbia. Portanto, o objetivo deste estudo foi comparar valores obtidos por diferentes equações de predição de VO2máx, com o VO2máx obtido pelo teste direto e verificar a aplicabilidade de equações obtidas por outros testes de campo, a partir do ISWT em jovens, do Centro de Ciências da Saúde ­ CCS da Universidade Estadual do Norte do Paraná (UENP), do sexo feminino, com idade entre 18 a 24 anos, não fumantes, e que não fossem suficientemente ativas ou atletas. As voluntárias foram submetidas ao teste de esforço máximo em esteira (ergoespitometria) e campo (ISWT). O VO2máx foi analisado de maneira indireta, utilizando-se diferentes equações de predição. Observou-se que, somente as equações de predição de Almeida et al. e a equação derivada de população brasileira (EB) reproduziram os valores do VO2máx obtidos na ergoespirometria, havendo relação moderada entre as variáveis da equação de Almeida et al., com validade concorrente aceitável. Assim, podemos concluir que os valores de VO2máx obtidos através de equações de predição podem reproduzir os valores encontrados no teste direto e a equação que leva em consideração a velocidade alcançada, poderia ser aplicável para se obter o VO2máx a partir do ISWT, em uma população jovem....(AU)

The evaluation of cardiorespiratory ability is performed through the maximal oxygen consumption (VO2max), which is the most widespread measure of aerobic ability in young people and the best physiological parameter to evaluate the functional capacity of the cardiorespiratory system, usually measured, directly, by spirometry.In order to facilitate the evaluation of VO2max, prediction equations originating from general characteristics of the individuals are used, or from the performance in field tests, such as the "Incremental Shuttle Walk Test" (ISWT). From the performance in the test, VO2max prediction equations are used to estimate the aerobic fitness. Therefore, the objective of this study was to compare values obtained by different VO2max prediction equations, with the VO2max obtained by the direct test and to verify the applicability of equations obtained by other field tests, from the ISWT in youngsters, from the Health Sciences Center ­ HSC, of State University of Northern Paraná (UENP), female, with age from 18 to 24 years, nonsmokers, and they were not sufficiently active or athletes. The volunteers were submitted to maximal exercise test on a treadmill (ergoespirometry) and field. The VO2max was analyzed indirectly, using different types of equations by distance traveled in ISWT. It was observed that only the prediction equations Almeida et al. and the equation derived from the brazilian population (EB) reproduced the VO2max values obtained in the spirometry, with moderate relation between the variables of the equation of Almeida et al., with acceptable concurrent validity. Thus, we can conclude that the values of VO2max obtained through prediction equations can reproduce the values found in the direct test and the equation that takes into account the speed reached could be applicable to obtain the VO2max from the ISWT in a population young....(AU)

Oxidative and proteolysis-related parameters of skeletal muscle from hamsters with experimental pulmonary emphysema: a comparison between papain and elastase induction.

The objective of this study was to investigate whether emphysema induced by elastase or papain triggers the same effects on skeletal muscle, related to oxidative stress and proteolysis, in hamsters. For this purpose, we evaluated pulmonary lesions, body weight, muscle loss, oxidative stress (thiobarbituric acid-reactive substances, total and oxidized glutathiones, chemiluminescence stimulated by tert-butyl hydroperoxide and carbonyl proteins), chymotrypsin-like and calpain-like proteolytic activities and muscle fibre cross-sectional area in the gastrocnemius muscles of emphysemic hamsters. Two groups of animals received different intratracheal inductions of experimental emphysema: by 40 mg/ml papain (EP) or 5.2 IU/100 g animal (EE) elastase (n = 10 animals/group). The control group received intratracheal instillation of 300 µl sterile NaCl 0.9%. Compared with the control group, the EP group had reduced muscle weight (18.34%) and the EE group had increased muscle weight (8.37%). Additionally, tert-butyl hydroperoxide-initiated chemiluminescence, carbonylated proteins and chymotrypsin-like proteolytic activity were all elevated in the EP group compared to the CS group, while total glutathione was decreased compared to the EE group. The EE group showed more fibres with increased cross-sectional areas and increased calpain-like activity. Together, these data show that elastase and papain, when used to induce experimental models of emphysema, lead to different speeds and types of adaptation. These findings provide more information on choosing a suitable experimental model for studying skeletal muscle adaptations in emphysema.

Effect of sodium hypochlorite and peracetic acid on the surface roughness of acrylic resin polymerized by heated water for short and long cycles.

OBJECTIVE: To evaluate the surface roughness of acrylic resin submitted to chemical disinfection via 1% sodium hypochlorite (NaClO) or 1% peracetic acid (C2H4O3). MATERIALS AND METHODS: The disc-shaped resin specimens (30 mm diameter ×4 mm height) were polymerized by heated water using two cycles (short cycle: 1 h at 74°C and 30 min at 100°C; conventional long cycle: 9 h at 74°C). The release of substances by these specimens in water solution was also quantified. Specimens were fabricated, divided into four groups (n = 10) depending on the polymerization time and disinfectant. After polishing, the specimens were stored in distilled deionized water. Specimens were immersed in 1% NaClO or 1% C2H4O3 for 30 min, and then were immersed in distilled deionized water for 20 min. The release of C2H4O3 and NaClO was measured via visual colorimetric analysis. Roughness was measured before and after disinfection. Roughness data were subjected to two-way ANOVA and Tukey's test. RESULTS: There was no interaction between polymerization time and disinfectant in influencing the average surface roughness (Ra, P = 0.957). Considering these factors independently, there were significant differences between short and conventional long cycles (P = 0.012), but no significant difference between the disinfectants hypochlorite and C2H4O3 (P = 0.366). Visual colorimetric analysis did not detect release of substances. CONCLUSION: It was concluded that there was the difference in surface roughness between short and conventional long cycles, and disinfection at acrylic resins polymerized by heated water using a short cycle modified the properties of roughness.