Role of 3Y-TZP grain boundaries in glazing and layering.

Objectives: Monolithic 3 mol% Yttria-stabilized tetragonal zirconia polycrystal or 3Y-TZP exhibits transformation toughening phenomena which is suitable for dental restorations with minimizing the risk of fracture and to decrease reduction of natural tooth. However, the staining/glazing or layering is required to achieve of a match with the optical properties of natural dentition. The hypothesis under examination is that the physical, chemical, and structural aspects of the 3Y-TZP grain boundaries after the staining/glazing or layering.

Effect of geometrical structure variations on strength and damage onset of cortical bone using multi-scale cohesive zone based finite element method.

Three-dimensional multi-scale finite element models were designed to examine the effects of geometrical structure variations on the damage onset in cortical bone at multiple structural scales. A cohesive zone finite element approach, together with anisotropic damage initiation criteria, is used to predict the onset of damage. The finite element models are developed to account for the onset of microdamage from the microscopic length scales consisting of collagen fibres, to the macroscopic level consisting of osteons and the Haversian canals.

Optical properties of zirconia ceramics for esthetic dental restorations: A systematic review.

Statement Of Problem: Yttria-stabilized tetragonal zirconia polycrystal has been used as a dental biomaterial for several decades because the fracture toughness and bend strength are increased by a stress-induced transformation-toughening mechanism. However, its esthetics are compromised by its poor translucency and grayish-white appearance.

Purpose: The purpose of the present systematic review was to assess information on the mechanical, chemical, and optical requirements of monolithic zirconia dental restorations.

Mechanical behaviour of porous hydroxyapatite.

The aim of the study was to investigate the role of microstructure and porosity on the mechanical behaviour of sintered hydroxyapatite. Hydroxyapatite disks with four different porosities were used in this investigation. With a nanoindentation system, elastic modulus, hardness, contact stress-strain relationship, energy absorption and indentation creep behaviour were investigated.

Development of graded hydroxyapatite/CaCO(3) composite structures for bone ingrowth.

Ceramic composites composed of constituents with different bone cell reactions present an interesting consideration for a new bone replacement material. The first component of the composite used in this study, hydroxyapatite, is known to be replaced by natural tissue significantly slower than the second, calcium carbonate, which has limited structural stability. A graded hydroxyapatite/calcium carbonate composite with bimodal component distribution was developed using a combined slip infiltration and dip-coating technique from a porous polyurethane sponge replica.