Passo Fundo, Brazil
Passo Fundo, Brazil

The University of Passo Fundo , also known as UPF, is a Brazilian private university. Founded in 1968, it is located in the city of Passo Fundo, in the state of Rio Grande do Sul. Wikipedia.

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Benetti P.,University Of Passo Fundo | Kelly J.R.,University of Connecticut | Sanchez M.,FMC Technologies | Della Bona A.,University Of Passo Fundo
Dental Materials | Year: 2014

Objectives To assess transient and residual stresses within the porcelain of veneered restorations (zirconia and metal) as a result of cooling rate and porcelain thickness. Methods Porcelain-on-zirconia (PZ) and porcelain-fused-to- metal (PFM) crowns were fabricated with 1 or 2 mm of porcelain. Thermocouples were attached both internally and externally to the crowns to record transient temperatures. For fast cooling, the furnace was opened after the holding time and switched off. Slow cooling was accomplished by opening the furnace at 50°C below the glass transition temperature (Tg) of the material. An axially symmetric FEA model simulated thermal stresses. Time-dependent temperature equations from thermocouple readings were set as boundary conditions. Framework materials and the porcelain below Tg were considered to behave elastically. Visco-elastic behavior was assumed for porcelain above the Tg modeling properties as dependent on cooling rate. Results Differences in residual stress were found for fast and slow cooled PZ and PFM crowns. Significant transient stress waves were observed within the porcelain when fast cooling through Tg. They are believed to be related to non-uniform volumetric changes originated from thermal gradients. Results were confirmed by modeling and physical testing of crowns containing a defect. Significance Residual stresses do not distinguish PZ from PFM. High magnitude transient stresses observed within the porcelain during fast cooling may explain clinical fractures involving internal defects. Stress waves may also originate internal micro-cracking which could grow under function. Therefore, slow cooling, especially for all-ceramic crowns with thick porcelain, is important to prevent thermal gradients and high-magnitude transient stresses. © 2014 Academy of Dental Materials.

Kelly J.R.,University of Connecticut Health Center | Benetti P.,São Paulo State University | Rungruanganunt P.,University of Connecticut Health Center | Bona A.D.,University Of Passo Fundo
Dental Materials | Year: 2012

Objectives: This paper attempts to provide critical perspectives on common in vitro research methodologies, including shear bond testing, wear testing, and load-to-failure tests. Origins of interest in high-quality laboratory data is reviewed, in vitro data is categorized into property and simulation protocols, and two approaches are suggested for establishing clinical validity. It is hoped that these insights will encourage further progress toward development of in vitro tests that are validated against clinical performance and/or by producing clinically validated failure or damage mechanisms. Materials and methods: Published shear and tensile bond data (macro and micro) is examined in light of published finite element analyses (FEA). This data is subjected to a Weibull scaling analysis to ascertain whether scaling is consistent with failure from the bonded interface or not. Wear tests results are presented in light of the damage mechanism(s) operating. Quantitative wear data is re-examined as being dependent upon contact pressure. Load-to-failure test results are re-analyzed by calculating contact stresses at failure for 119 tests from 54 publications over more than 25 years. Results: FEA analyses and reported failure modes (adhesive, mixed, cohesive) are consistent with failure not involving interfacial "shear stresses" as calculated in published work. Weibull scaling clearly suggests failure involving external surfaces of specimens, not interfacial origins. Contact stresses (pressures) are clearly an important variable in wear testing and are not well-controlled in published work. Load-to-failure tests create damage not seen clinically due to excessively high contact stresses. Most contact stresses in the 119 tests examined were calculated to be between 1000 MPa and 5000 MPa, whereas clinical contact stresses at wear facets have been measured not to exceed 40 MPa. Conclusions: Our community can do a much better job of designing in vitro tests that more closely simulate clinical conditions, especially when contact is involved. Journals are encouraged to thoughtfully consider a ban on publishing papers using bond tests and load-to-failure methods that are seriously flawed and have no clinical relevance. © 2011 Academy of Dental Materials.

Rosa V.,University Of Passo Fundo | Della Bona A.,University Of Passo Fundo | Cavalcanti B.N.,University of Taubaté | Nor J.E.,University of Michigan
Dental Materials | Year: 2012

Tissue engineering is an interdisciplinary field that combines the principles of engineering, material and biological sciences toward the development of therapeutic strategies and biological substitutes that restore, maintain, replace or improve biological functions. The association of biomaterials, stem cells, growth and differentiation factors has yielded the development of new treatment opportunities in most of the biomedical areas, including Dentistry. The objective of this paper is to present the principles underlying tissue engineering and the current scenario, the challenges and the perspectives of this area in Dentistry. Significance: The growth of tissue engineering as a research field has provided a novel set of therapeutic strategies for biomedical applications. Indeed, tissue engineering may lead to new strategies for the clinical management of patients with dental and craniofacial needs in the future. © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

The objective of this study was to estimate the relative soil bulk density (RD) from a pedotransfer function of maximum bulk density (MBD). Undisturbed and disturbed soil samples of 10 soils, under no tillage, established for more than 10 years, were collected in Rio Grande do Sul State, Brazil, at 5 to 30 cm depths. Granulometry, organic matter (OM), bulk density (BD) and MBD were determined by Proctor test. A pedotransfer function was developed with these values to obtain the MBD from the clay and OM contents in the soil. Our conclusion is that the MBD = 2.03133855 - 0.00320878 OM - 0.00076508 clay function can be used to estimate the RD of the soils studied.

Geib L.T.C.,University Of Passo Fundo
Ciencia e Saude Coletiva | Year: 2012

Health is affected throughout the course of life by characteristics of social context, which produce inequalities in terms of exposure and vulnerability. These social determinants interfere with the well-being, functional independence and quality of life of the elderly, but are generally overlooked in interventions and policies. Therefore, the aim of this study was to systematize the knowledge of the social determinants of health in the elderly, using the Dahlgren and Whitehead model as a conceptual guide. The effects of demographic changes in the aging process and morbidity profile were approached at the structural level. The conditions of life and work with impact on current and future health and the role of social cohesion were studied at the intermediate level. Lastly, the behavior and lifestyles of major risk were examined at close quarters. It was detected that equity in health requires attention to social determinants during the course of life in order to minimize chronic diseases and deficiencies of the elderly, which reflect their social positions in early life.

de Medeiros G.F.,University Of Passo Fundo | Kripka M.,University Of Passo Fundo
Engineering Structures | Year: 2014

In addition to economic gains, the use of optimization strategies in the development of a structural design can reduce the consumption of materials whose extraction, manufacture and transport cause large environmental damage, as occurs with reinforced concrete inputs. The aim of the present study was to optimize the monetary and environmental costs associated with pieces of rectangular reinforced concrete columns submitted to uniaxial bending and compression loads, using the harmony search algorithm, which consists of a meta-heuristic approach analogous to the process of attaining the best musical harmony. Therefore, in addition to taking into account the purchasing costs of materials in the structural optimization process, analyses were conducted to determine the environmental costs of each input, estimated from the life-cycle analysis. The sizes of concrete section and the amount and gauges of the structures, as well as concrete strength, were used as variables. The columns were checked as to ultimate and serviceability limit states following the ABNT NBR 6118/07 Brazilian standard. Several indicators were used for environmental cost minimization, and the results were compared to those obtained from conventional sizing processes as well as from other optimization methods. In general, even with structure optimization to minimize monetary costs, important reductions in environmental costs are obtained, regardless of the indicator used for impact analysis, thus yielding cross-sections with different features. © 2013 Elsevier Ltd.

Della Bona A.,University Of Passo Fundo | Corazza P.H.,São Paulo State University | Zhang Y.,New York University
Dental Materials | Year: 2014

Objectives To characterize the microstructure and determine some mechanical properties of a polymer-infiltrated ceramic-network (PICN) material (Vita Enamic, Vita Zahnfabrik) available for CAD-CAM systems. Methods Specimens were fabricated to perform quantitative and qualitative analyses of the material's microstructure and to determine the fracture toughness (KIc), density (ρ), Poisson's ratio (ν) and Young's modulus (E). KIc was determined using V-notched specimens and the short beam toughness method, where bar-shaped specimens were notched and 3-point loaded to fracture. ρ was calculated using Archimedes principle, and ν and E were measured using an ultrasonic thickness gauge with a combination of a pulse generator and an oscilloscope. Results Microstructural analyses showed a ceramic- and a polymer-based interpenetrating network. Mean and standard deviation values for the properties evaluated were: KIc = 1.09 ± 0.05 MPa m 1/2, ρ = 2.09 ± 0.01 g/cm3, ν = 0.23 ± 0.002 and E = 37.95 ± 0.34 GPa. Significance The PICN material showed mechanical properties between porcelains and resin-based composites, reflecting its microstructural components. © 2014 Academy of Dental Materials.

Colpani J.T.,University Of Passo Fundo | Borba M.,University Of Passo Fundo | Della Bona A.,University Of Passo Fundo
Dental Materials | Year: 2013

Objectives: (1) To measure the marginal and internal adaptation of different prosthetic crowns infrastructures (IS); (2) to analyze two types of methodologies (replica and weight technique) used to evaluate the adaptation of indirect restorations. Methods: Ceramic IS were fabricated using CAD/CAM technology and slip-casting technique, and metal IS were produced by casting (n = 10). For each experimental group, the adaptation was evaluated with the replica (RT) and the weight technique (WT), using an impression material (low viscosity silicon) to simulate the luting agent. Cross-sectional images of the silicon replica were obtained and analyzed with Image J software to measure the low viscosity silicon layer thickness at pre-determined points. The silicon layer was also weighted. Results were statistically analyzed with ANOVA and Tukey's test (α = 0.05). Pearson correlation was used to analyze the relation between the two types of evaluation methods. Results: All IS evaluated showed clinically acceptable internal and marginal adaptation. Metal IS showed the best adaptation, irrespective of the measuring technique (RT and WT). The IS produced by CAD-CAM showed greater gap values at the occlusal area than at other evaluated regions. The IS produced by the dental laboratory technician showed similar gap values at all evaluated regions. There is no correlation between RT and WT (p > 0.05). Significance: Different levels of adaptation were found for the different experimental groups and for the different evaluation methods. However, all IS evaluated showed clinically acceptable values of marginal and internal adaptation. © 2012 Academy of Dental Materials.

Benetti P.,São Paulo State University | Della Bona A.,University Of Passo Fundo | Kelly J.R.,University of Connecticut Health Center
Dental Materials | Year: 2010

Objectives: To test the hypotheses that shear bond strength (σ s) and contact angle (θ) are influenced by the thermal expansion/contraction behavior of bilayered all-ceramic systems. Methods: Glass-infiltrated ceramics (A - In-Ceram ALUMINA) and zirconia-reinforced alumina (Z - In- Ceram ZIRCONIA) were veneered with feldspathic ceramics (7 - VM7; 9 - VM9; 13 - VM13), yielding 6 experimental groups. Surface roughness (Ra) of A and Z core ceramic disks (12 mm diameter × 1.2 mm high) was measured to assure that values were similar. A cylinder of veneer (2 mm diameter × 2 mm high) was fired onto the center of all core disks, cooled under identical conditions and tested for σ s to failure (n = 20). For the θ evaluation (n = 10) similar specimens (veneer 1 mm high) were overfired to develop an equilibrium θ that was then measured from digital images (AutoCAD 2006). Published thermal expansion data were used. Results: The mean values of σ s (MPa) and θ (°) for the core-veneer ceramic groups were, respectively: A7 (19.4 ± 4.7; 49 ± 4.7); Z7 (23.4 ± 6.2; 56 ± 4.9); A9 (0.9 ± 1.6; 55 ± 5.8); Z9 (9.8 ± 5.7; 59.8 ± 2.9); A13 (0; 70 ± 6.0); Z13 (0; 67.2 ± 6.3). As the difference in coefficient of thermal expansion (coreveneer) increases, the θ value increases (r = 0.95) and the σ s value decreases (r = -0.92), p ≤ 0.01. Conclusion: The contact angle measurement and the shear bond strength test of core-veneer ceramics are influenced by the thermal expansion behavior of these all-ceramic systems. © 2010 Academy of Dental Materials.

There has been an increase of chronic diseases with the subsequent need for care and hospitalization, due to the acceleration of the elderly demographic growth. The objective of the present paper is to reflect on the care of nursing and the autonomy of the human being under the condition of elderly hospitalization. Nursing professionals, caring in the hospital ambient, can contribute significantly for the construction of the elderly autonomy and participation on the decision making about their need for attention or health care. The ethics redeeming, under a worthy aging perspective, permeates several discussions in the aging society and, specifically, among health professionals who act in hospital institutions.

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