Survival rate, load to fracture, and finite element analysis of incisors and canines restored with ceramic veneers having varied preparation design

Purpose: To evaluate the survival rate, success rate, load to fracture, and finite element analysis (FEA) of maxillary central incisors and canines restored using ceramic veneers and varying preparation designs.Methods and Materials: Thirty human maxillary central incisors and 30 canines were allocated to the following four groups (n=15) based on the preparation design and type of tooth: Gr1 = central incisor with a conservative preparation; Gr2 = central incisor with a conventional preparation with palatal chamfer; Gr3 = canine with a conservative preparation; Gr4 = canine with a conventional preparation with palatal chamfer. Ceramic veneers (lithium disilicate) were fabricated and adhesively cemented (Variolink Veneer). The specimens were subjected to 4 x 106 mechanical cycles and evaluated at every 500,000 cycles to detect failures. Specimens that survived were subjected to a load to fracture test. Bidimensional models were modeled (Rhinoceros 4.0) and evaluated (MSC.Patrans 2005r2 and MSC.Marc 2005r2) on the basis of their maximum principal stress (MPS) values. Survival rate values were analyzed using the Kaplan-Meier test (alpha = 0.05) and load to fracture values were analyzed using the Student t-test (alpha = 0.05).Results: All groups showed 100% survival rates. The Student t-test did not show any difference between the groups for load to fracture. FEA showed higher MPS values in the specimens restored using veneers with conventional preparation design with palatal chamfer.Conclusion: Preparation design did not affect the fracture load of canines and central incisors, but the veneers with conventional preparation design with palatal chamfer exhibited a tendency to generate higher MPS values.

Effect of thermo-mechanical load cycling on silorane-based composite restorations

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Projeto e construção de uma célula de carga acoplada a uma grampeadeira

Due to greater productivity in the auto industry and the high competition in the current market, employees are required to perform repeated movements and often, with short intervals of rest. This daily exposure causes muscle tension and overloads occasional, thus creating problems and psychosocial stress. Currently companies are concerned with the welfare of the employee, where the main focus is product quality and life of the worker, thus justifying such a study. Therefore , this technical work to assist the master's thesis of graduate student Daniel Rodriguez , was developed with the objective is to analyze , develop, design and construct a coupled to a load cell device simulating a stitcher to be used in an industry the posts stapling upholstery of seats . Are the stages of design and construction detailed in this work and its positive results in relation to the technical part of the study

Validação de uma escala colorida de esforço percebido para adultas jovens e idosas em caminhada na esteira

The perceived exertion has been used for the intensity control and exercise prescription. Among the various scales that estimate the perceived exertion, the Borg’s RPE scale is one of the best known. However, for populations with low levels of schooling or with visual difficulties such as the elderly, the application of these scales becomes more difficult. In previous studies, a color scale of perceived exertion was developed to aim for assistance in application of the scale and interpretation of perceived exertion. This scale showed high correlation with the Borg’s scale and proved to be valid to estimate the perceived exertion. Thereby, the aim of this study was to assess the validity of the color scale of perceived exertion to measure the perceived exertion in adult women of different ages. Participated in the study 12 young adult women with age of 21,7 ± 1,5 years old, and 10 elderly women with age of 60,3 ± 3,5 years old. The participants were submitted to an incremental exercise of treadmill walking with stages of 2 minutes duration. The inicial load was 5,5 km/h and inclination of 6% for young women and 2% for elderly women, both with 2% increments at each stage completed, without changing the speed. Heart rate and oxygen comsuption responses were determined at the 30 finals seconds of each stage. At the 60 finals seconds of each stage participants indicated the perceived exertion for the overall body, for the legs and for the chest, primarily in the color scale and following in the tradicional Borg’s scale. The analysis of variance for repeated measures was used to assess the effect of different loads on the perceived exertion and physiological responses. The correlations betwen physiological variables, color scale and Borg’s scale were analyzed in group and individually. In all analysis the significance...(Complete abstract click electronic access below)

Relação entre a disparidade de força entre membros inferiores e estabilidade postural em atletas de voleibol

Volleyball is a sport in which the laterality dominant limb shows superior strength and coordination because of its preferential use. Asymmetrical tendencies during the landing after the jump when striking or blocking actions are predominant for most part of game (ARRUDA; EDUARDO, 2008). Adaptations include imbalance of forces in static and dynamic motions at the knee joint, which increases risk for injury. Also, asymmetries in balance control during jumping and landing associate with a general postural instability that can be observed during static balance tasks. The purpose of this study was to investigate relationship between unequal lower limb strength (muscle imbalance) and postural stability levels in volleyball athletes and non-athletes. Nine female volleyball athletes and 10 active non-athletes participated in this study. Four encouters with participants were scheduled: three encounters in the bodybuilding gymnasium to collect anthropometric measures (weight, height for BMI, thigh circumference, which provided an initial diagnosis about asymmetry), and to perform the isometric strength test (i.e., leg press using a load cell and a force transducer to calculate uni an bilateral strength). The last encounter was in the laboratory where a balance test on a force platform was administered under five test conditions, with three repetitions each: baseline (natural standing position), one-leg standing, right side, with full vision (D_CV), and blindfolded (D_SV), one-leg standing, left side, with full vision (E_CV), and blindfolded (E_SV). The stability levels were evaluated using the path length parameters which was based on the total displacement of the center of pressure (DTCP). . Both groups shows asymmetric strength levels between legs, with better performance for the right leg. An ANOVA three way using the DTCP for the CV condition, legs (D x E), trials (3) with repeated measures for the first two factors and with a between (three)...

Efeito da manipulação do feedback da percepção subjetiva de esforço esperada na percepção subjetiva de esforço e no desempenho de adultos de diferentes faixas etárias

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Microhardness of the enamel exposed to whitening dentifrices

The purpose of this study is to verify the effect of three different types of dentifrices on the superficial microhardness of bovine enamel. Methods: Forty-eight 4x4mm dental fragments were polished and randomly divided into 4 groups: GI, conventional silica-based dentifrice; GII, hydrogen peroxide-based dentifrice; GIII, carbamide peroxide-based dentifrice; and GIV, immersion in artificial saliva. After polished, the specimens received five indentations of 25g static load, for 5 seconds. Subsequently, specimens from groups GI, GII and GIII were immersed in solution containing dentifrice and distilled water, in weight proportion of 1:2, for 15 minutes daily. After this period, fragments were rinsed in tap water and stored in artificial saliva at 37oC. This procedure was repeated for 21 days and then a new analysis of the microhardness was performed. Results and conclusion: The results were submitted to ANOVA and Fisher’s test at 5%. It was concluded that all samples treated with dentifrices showed hardness decrease, being most pronounced in dentifrices containing peroxide.

Influence of standard load micro and nanopatterned in surface roughness of bleached teeth and submitted to different surface treatments?

The aim of this study was evaluate the dental enamel after whitening treatment with Opalescence Boost PF® 38%, correlating the structural alterations in the surface of the enamel with its respective pH and verify if whitened teeth submitted to different finishing and polishing techniques show similar surface texture to healthy teeth (control group). Sixty premolars were divided in 6 groups (n = 10), which had been immersed in artificial saliva during all the experiment. Protocol whitening was performed according to the manufacturer recommendations, and then the specimens were submitted to different polishing technique with Sof-Lex Pop On® disks, Flex Diamond® felt disks using two different micrometric polishing pastes (Enamelize® and Diamond Polish®) and two nanometric polishing pastes (Lummina-E Diamond and Lummina-E Alumina), according to the groups. Representative specimens were analyzed in scanning electronic microscopy (SEM). Whitening gel used in this experiment had modified the morphologic aspect of the enamel surface. It was found that two nanometric polishing pastes (G5 and G6) promoted a less rough surface compared to control group even after the whitening process.

Immunization of Wistar female rats with 255-Gy-irradiated Toxoplasma gondii: Tissue parasitic load and lactogenic quantification

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A step to the gigantic genome of the desert locust: chromosome sizes and repeated DNAs

The desert locust (Schistocerca gregaria) has been used as material for numerous cytogenetic studies. Its genome size is estimated to be 8.55 Gb of DNA comprised in 11 autosomes and the X chromosome. Its X0/XX sex chromosome determinism therefore results in females having 24 chromosomes whereas males have 23. Surprisingly, little is known about the DNA content of this locust's huge chromosomes. Here, we use the Feulgen Image Analysis Densitometry and C-banding techniques to respectively estimate the DNA quantity and heterochromatin content of each chromosome. We also identify three satellite DNAs using both restriction endonucleases and next-generation sequencing. We then use fluorescent in situ hybridization to determine the chromosomal location of these satellite DNAs as well as that of six tandem repeat DNA gene families. The combination of the results obtained in this work allows distinguishing between the different chromosomes not only by size, but also by the kind of repetitive DNAs that they contain. The recent publication of the draft genome of the migratory locust (Locusta migratoria), the largest animal genome hitherto sequenced, invites for sequencing even larger genomes. S. gregaria is a pest that causes high economic losses. It is thus among the primary candidates for genome sequencing. But this species genome is about 50 % larger than that of L. migratoria, and although next-generation sequencing currently allows sequencing large genomes, sequencing it would mean a greater challenge. The chromosome sizes and markers provided here should not only help planning the sequencing project and guide the assembly but would also facilitate assigning assembled linkage groups to actual chromosomes.

Influence of CAD-CAM diamond bur deterioration on surface roughness and maximum failure load of Y-TZP-based restorations

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inlays Made From a Hybrid Material: Adaptation and Bond Strengths

The aim of this study was to evaluate the internal fit, marginal adaptation, and bond strengths of inlays made of computer-aided design/computer-aided manufacturing feldspathic ceramic and polymer-infiltrated ceramic. Twenty molars were randomly selected and prepared to receive inlays that were milled from both materials. Before cementation, internal fit was achieved using the replica technique by molding the internal surface with addition silicone and measuring the cement thicknesses of the pulpal and axial walls. Marginal adaptation was measured on the occlusal and proximal margins of the replica. The inlays were then cemented using resin cement (Panavia F2.0) and subjected to two million thermomechanical cycles in water (200 N load and 3.8-Hz frequency). The restored teeth were then cut into beams, using a lathe, for microtensile testing. The contact angles, marginal integrity, and surface patterns after etching were also observed. Statistical analysis was performed using two-way repeated measures analysis of variance (p<0.05), the Tukey test for internal fit and marginal adaptation, and the Student t-test for bond strength. The failure types (adhesive or cohesive) were classified on each fractured beam. The results showed that the misfit of the pulpal walls (p=0.0002) and the marginal adaptation (p=0.0001) of the feldspathic ceramic were significantly higher when compared to those of the polymer-infiltrated ceramic, while the bond strength values of the former were higher when compared to those of the latter. The contact angle of the polymer-infiltrated ceramic was also higher. In the present study, the hybrid ceramic presented improved internal and marginal adaptation, but the bond strengths were higher for the feldspathic ceramic.

Axial loads on implant-supported partial fixed prostheses for external and internal hex connections and machined and plastic copings: strain gauge analysis

The aim of this in vitro study was to use strain gauge (SG) analysis to compare the effects of the implant-abutment joint, the coping, and the location of load on strain distribution in the bone around implants supporting 3-unit fixed partial prostheses. Three external hexagon (EH) implants and 3 internal hexagon (IH) implants were inserted into 2 polyurethane blocks. Microunit abutments were screwed onto their respective implant groups. Machined cobalt-chromium copings and plastic copings were screwed onto the abutments, which received standard wax patterns. The wax patterns were cast in a cobalt-chromium alloy (n = 5): group 1 = EH/machined. group 2 = EH/plastic, group 3 = IH/machined, and group 4 = IH/plastic. Four SGs were bonded onto the surface of the block tangentially to the implants. Each metallic structure was screwed onto the abutments and an axial load of 30 kg was applied at 5 predetermined points. The magnitude of microstrain on each SG was recorded in units of microstrain (mu epsilon). The data were analyzed using 3-factor repeated measures analysis of variance and a Tukey test (alpha = 0.05). The results showed statistically significant differences for the type of implant-abutment joint, loading point, and interaction at the implant-abutment joint/loading point. The IH connection showed higher microstrain values than the EH connection. It was concluded that the type of coping did not interfere in the magnitude of microstrain, but the implant/abutment joint and axial loading location influenced this magnitude.

Estimation of a preference map of new consumers for spatial load forecasting simulation methods using a spatial analysis of points

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Rotor Failure Diagnosis of Induction Motors by Wavelet Transform and Fourier Transform in Function of the Load

This paper presents two diagnostic methods for the online detection of broken bars in induction motors with squirrel-cage type rotors. The wavelet representation of a function is a new technique. Wavelet transform of a function is the improved version of Fourier transform. Fourier transform is a powerful tool for analyzing the components of a stationary signal. But it is failed for analyzing the non-stationary signal whereas wavelet transform allows the components of a non-stationary signal to be analyzed. In this paper, our main goal is to find out the advantages of wavelet transform compared to Fourier transform in rotor failure diagnosis of induction motors.