Mono-phase bio-ceramics (alumina and zirconia) are widely used as femoral heads in total hip replacements (THR) as an alternative to metal devices. Unfortunately, the orthopaedic community reports significant in-vivo failures. Material scientists are already familiar with composites like alumina zirconia. Since both are biocompatible, this could prove to be a new approach to implants. This pape...

background : chip-off fracture of veneering porcelain has been described as the most frequent reason for the failure of zirconia-based fi xed partial dentures. the purpose of this study was to evaluate the shear bond strength (sbs) of two commercial zirconia core ceramics to their corresponding veneering ceramics. materials and methods : zirconia disks with 7-mm diameter and 3-mm height were pr...

STATEMENT OF PROBLEM Successful long-term bonding to zirconia ceramic remains a challenge, requiring special cements and surface roughening by airborne-particle abrasion, which might negatively affect the ceramic. PURPOSE The purpose of this study was to evaluate the shear bond strength (SBS) of composite resin cylinders to a modified zirconia surface using different luting techniques after t...

STATEMENT OF PROBLEM Various surface treatments of zirconia have been recommended for veneering ceramics. However, it has not been determined which of these treatments produces the highest bond strength. PURPOSE This study examined the effects of various surface treatments on the shear bond strength of zirconia and veneering ceramic. MATERIAL AND METHODS Square-shaped (5 × 10 × 10 mm) zirco...

Alumina- and zirconia-based ceramic dental restorations are designed to repair functionality as well as esthetics of the failed teeth. However, these materials exhibited several performance deficiencies such as fracture, poor esthetic properties of ceramic cores (particularly zirconia cores), and difficulty in accomplishing a strong ceramic-resin-based cement bond. Therefore, improving the mech...

STATEMENT OF PROBLEM Zirconia-based restorations have the common technical complication of delamination, or porcelain chipping, from the zirconia core. Thus the shear bond strength between the zirconia core and the veneering porcelain requires investigation in order to facilitate the material's clinical use. PURPOSE The purpose of this study was to evaluate the bonding strength of the porcela...

objectives: fracture strength is an important factor influencing the clinical long-term success of implant-supported prostheses especially in high stress situations like excessive crown height space (chs). the purpose of this study was to compare the fracture strength of implant-supported fixed partial dentures (fpds) with excessive crown height, fabricated from three different materials. mater...

INTRODUCION: Improved wear resistance of crosslinked UHMWPE has been well demonstrated in both hip and knee [1-4]. A reduction of 70% can be shown in knee simulators from conventional crosslinked tibial inserts (CXPE) gamma-irradiated at 3.5Mrad to 7Mrad highly crosslinked inserts (HXPE). Hip simulator models indicated that debris size decreased with increased crosslinking [5]. In the knee it h...

Metal sulfate formation is one of the major challenges to the emission aftertreatment catalysts. Unlike the incredibly sulfation prone nature of Pd to form PdSO4, no experimental evidence exists for PtSO4 formation. Given the mystery of nonexistence of PtSO4, we explore PtSO4 using a combined approach of an evolutionary algorithm based search technique and quantum mechanical computations. Exper...