Analysis of primary stability of dental implants inserted in different substrates using the pullout test and insertion torque

The aim of the study was to evaluate mechanical behavior of implants inserted in three substrates, by measuring the pullout strength and the relative stiffness. 32 implants (Master Porous-Conexao, cylindrical, external hexagon, and surface treatment) were divided into 4 groups (n = 8): pig rib bone, polyurethane Synbone, polyurethane Nacional 40 PCF, and pinus wood. Implants were installed with the exact distance of 5 mm of another implant. The insertion torque (N·cm) was quantified using the digital Kratos torque meter and the pullout test (N) was performed by an axial traction force toward the long axis of the implant (2 min/mm) through mount implant devices attached to a piece adapted to a load cell of 200 Kg of a universal testing machine (Emic DL10000). Data of insertion torque and maximum pullout force were submitted to one-way ANOVA and Bonferroni tests (α = 0.05). Polyurethane Nacional 40 PCF and pinus wood showed the highest values of insertion torque and pullout force, with significant statistical difference (P < 0.05) with other groups. The analysis showed stiffness materials with the highest values for primary stability. © 2013 Nathalia Ferraz Oliscovicz et al.

Desarrollo económico y social y las relaciones externas de América Latina = Economic and social development and external relations of Latin America

Incluye Bibliografía

Desarrollo económico y social y las relaciones económicas externas de América Latina = Economic and social development and the external economic relations of Latin America

Incluye Bibliografía

External desequilibrium in the economic development of Latin America: the case of Mexico

Includes bibliography

Latin American development and the international economic situation: second regional appraisal of the international development strategy, part 2: the external economic relations of Latin America and the international situation

Incluye Bibliografía

Políticas de ajuste y renegociación de la deuda externa = Adjustment policies and renegotiation of the external debt

Incluye Bibliografía

Problema de la deuda: gestación, desarrollo, crisis y perspectiva = Problem of the external debt: gestation, development, crisis and prospects = Le probleme de la dette: gestation, evolution, crise et perspectives

Incluye Bibliografía

External economic relations of Latin America in the 1980s

Includes bibliography

Adsorption of polyelectrolytes onto oppositely charged cylindrical macroions

In this work we investigate the adsorption of polyelectrolyte chains onto uniformly charged cylindrical macroions by means of the Metropolis Monte Carlo simulations and weighted histogram analysis method. Adopting a simplified model for macromolecules and treating the electrolytic solution in the Debye-Hückel level, conformational properties of the adsorbed chain, such as the radius of gyration and the thickness of the adsorbed layer, are provided as a function of ionic strength and macroion charge density. By analysis of the free energy profile as a function of the radius of gyration it was possible to identify first-order-like transitions between adsorbed and desorbed states and obtain a macroion charge density dependence of the critical ionic strength in good agreement with experiments. © 2013 AIP Publishing LLC.