Proponents of the biological theory of aseptic loosening have in recent years tended to concentrate on the production and distribution of particulate ultra-high-molecular-weight polyethylene (UHMWPE) debris around the potential joint space. However, mechanical loading of cemented implants with the differing elastic moduli of metal stems, polymethylmethacrylate (PMMA) cement and bone can result ...

OBJECTIVES A comparative study on the stress distribution in the dentine and cement layer of an endodontically treated maxillary incisor has been carried out by using Finite Element Analysis (FEA). The role of post and cement rigidity on reliability of endodontic restorations is discussed. METHODS A 3D FEM model (13,272 elements and 15,152 nodes) of a central maxillary incisor is presented. A...

The objective of this study was to analyze the distribution of tensile stresses in indirect restorations prepared in several composite cavity bases. Elastic moduli of 20 materials were measured by nanoindentation technique for finite element analysis. Axisymmetric models of posterior onlays were constructed using combinations of two onlay materials and three cavity base materials. Thickness of ...

The monitoring of both linear and nonlinear elastic properties of a high performance concrete during curing is presented by application of compressional and shear waves. To follow the linear elastic behavior, both compressional and shear waves are used in wide band pulse echo mode. Through the value of the complex reflection coefficient between the cell material (Lucite) and the concrete within...

Introduction The main function of acrylic bone cement is to transfer loads from the prosthesis to the cancellous bone or increase the load carrying capacity of the surgical prosthesis. If the imposed stresses are greater than the load carrying capability, then cement fracture may occur resulting in failure of the joint replacement. The fracture of the cement mantle and subsequent premature loos...

Fiber reinforced concretes (FRCs) exhibit property improvement caused by the fibers. By using gamma radiation we have further improved mechanical properties of hydraulic concretes elaborated with Portland cement, water, silica sand, marble and polypropylene (PP) fibers. Compression strength, compression modulus, impact strength and dynamic elastic modulus were determined. Impact fatigue testing...

Cement setting and cohesion are governed by the precipitation and growth of calcium-silicate-hydrate, through a complex evolution of microstructure. A colloidal model to describe nucleation, packing, and rigidity of calcium-silicate-hydrate aggregates is proposed. Polydispersity and particle size dependent cohesion strength combine to produce a spectrum of packing fractions and of corresponding...

a r t i c l e i n f o The setting of cement paste is widely understood to be caused by percolation of the links that are created by overlap of hydration products on the surfaces of reacting grains of clinker. Percolation theory predicts that the elastic modulus will increase with a certain functional form, but few attempts have been made to demonstrate this behavior quantitatively. We discuss t...

Based on the thermo elasticity, using finite element method to analyze the stress of femur-prosthesis system when the hip joint has been replaced, a reference for the selection of prosthesis material is presented after discussing the thermo physical property of material which has an effect on the stress of femur-prosthesis system. We assume that prosthesis, bone cement and femur are linear elas...

The main strategy to reduce the environmental impact of the concrete industry is to reuse the waste materials. This research has considered the combination of cement replacement by industrial by-products, and natural coarse aggregate substitution by recycled aggregate. The aim is to evaluate the behavior of concretes with a reduced impact on the environment by replacing a 50% of cement by indus...