Evaluation of the Bond Strength between the Acrylic Teeth and Reinforced or Non-reinforced Complete Denture Base.

Objective: The aim of this study was to examine whether the method of surface treatment of the acrylic teeth and reinforcement of the denture base (carbon fibers) affect the reduction of stress concentration for gap initiation at the interface of acrylic teeth and denture base as a measure of bond strength.

Materials And Methods: Samples of cross-sections of acrylic teeth and denture base were isolated from four pairs of complete acrylic dentures (with and without reinforcement of the denture base) and were subsequently subjected to compressive loading in a universal testing machine simulating two different occlusions. Selected groups of acrylic teeth (central incisors, first premolars, and first molars) from complete dentures were treated in various ways (untreated, mechanical, chemical, and mechanical-chemical).

Evolution of chemically induced cracks in alkali feldspar: thermodynamic analysis.

Unlabelled: A system of edge cracks was applied to polished (010) surfaces of K-rich gem-quality alkali feldspar by diffusion-mediated cation exchange between oriented feldspar plates and a Na-rich NaCl-KCl salt melt. The cation exchange produced a Na-rich layer at and beneath the specimen surface, and the associated strongly anisotropic lattice contraction lead to a tensile stress state at the specimen surface, which induced fracturing. Cation exchange along the newly formed crack flanks produced Na-enriched diffusion halos around the cracks, and the associated lattice contraction and tensile stress state caused continuous crack growth.

Total Knee Replacement with an Uncemented Porous Tantalum Tibia Component: A Failure Analysis.

Porous tantalum has been extensively used in orthopaedic surgery, including uncemented total knee arthroplasty (TKA). Favourable results were reported with earlier monobloc tibial components and the design evolved to modular implants. We aimed to analyse possible causes for extensive medial tibia bone loss, resulting in modular porous tantalum tibia baseplate fracture after primary TKA.

The Numerical Modelling Approach with a Random Distribution of Mechanical Properties for a Mismatched Weld.

The aim of this work was to include a local variation in material properties to simulate the fracture behaviour in a multi-pass mis-matched X-weld joint. The base material was welded with an over and under-match strength material. The local variation was represented in a finite element model with five material groups in the weld and three layers in the heat-affected zone.

Bilateral neck fracture in bimodular femoral stem after primary total hip arthroplasty: a case report.

Background: Bi-modular stems were introduced in primary total hip arthroplasty (THA) to enable better control of the femoral offset, leg length, and hip stability. Despite numerous reports on modular femoral neck fractures, some designs are still marketed worldwide. While the risk factors for the sudden failure are multifactorial and mostly known, the timing of this new THA complication is not predictable by any means.

Damage tolerance of lamellar bone.

Lamellar bone is known to be the most typical structure of cortical bone in large mammals including humans. This type of tissue provides a good combination of strength and fracture toughness. As has been shown by John D Currey and other researchers, large deformations are associated with the appearance of microdamage that optically whitens the tissue, a process that has been identified as a contribution to bone toughness.

Modular femoral neck failure after revision of a total hip arthroplasty: a finite element analysis.

The authors report on a case of modular femoral neck fracture which appeared 21 months after revision of acetabular component. The revision surgery was performed 8 years after the primary total hip arthroplasty due to aseptic loosening of the acetabular component. During acetabular revision, the primary implanted short (S, - 3.