비만아 부모의 돌봄 경험: q 방법론

http://www.ibmc.up.pt/projectos/FJMonteiro/Bonamidi%20Project/References%20Bonamidi/Denry%20-%20State%20of%20the%20art%20zirconia%20dental%20applications.pdf

State of the art of zirconia for dental applications

At present, strong requirements in orthopaedics are still to be met, both in bone and joint substitution and in the repair and regeneration of bone defects. In this framework, tremendous advances in the biomaterials field have been made in the last 50 years where materials intended for biomedical purposes have evolved through three different generations, namely first generation (bioinert materials), second generation (bioactive and biodegradable materials) and third generation (materials designed to stimulate specific responses at the molecular level). In this review, the evolution of different metals, ceramics and polymers most commonly used in orthopaedic applications is discussed, as well as the different approaches used to fulfil the challenges faced by this medical field.

https://royalsocietypublishing.org/doi/pdf/10.1098/rsif.2008.0151

Biomaterials in orthopaedics.

Zirconia ceramics have found broad applications in a variety of energy and biomedical applications because of their unusual combination of strength, fracture toughness, ionic conductivity, and low thermal conductivity. These attractive characteristics are largely associated with the stabilization of the tetragonal and cubic phases through alloying with aliovalent ions. The large concentration of vacancies introduced to charge compensate of the aliovalent alloying is responsible for both the exceptionally high ionic conductivity and the unusually low, and temperature independent, thermal conductivity. The high fracture toughness exhibited by many of zirconia ceramics is attributed to the constraint of the tetragonal-to-monoclinic phase transformation and its release during crack propagation. In other zirconia ceramics containing the tetragonal phase, the high fracture toughness is associated with ferroelastic domain switching. However, many of these attractive features of zirconia, especially fracture toughness and strength, are compromised after prolonged exposure to water vapor at intermediate temperatures (∼30°–300°C) in a process referred to as low-temperature degradation (LTD), and initially identified over two decades ago. This is particularly so for zirconia in biomedical applications, such as hip implants and dental restorations. Less well substantiated is the possibility that the same process can also occur in zirconia used in other applications, for instance, zirconia thermal barrier coatings after long exposure at high temperature. Based on experience with the failure of zirconia femoral heads, as well as studies of LTD, it is shown that many of the problems of LTD can be mitigated by the appropriate choice of alloying and/or process control.

The Tetragonal-Monoclinic Transformation in Zirconia: Lessons Learned and Future Trends

What future for zirconia as a biomaterial

High-tech ceramics have always been associated to medical devices: they are used today as femoral heads and acetabular cups for total hip replacement, dental implants and restorations, bone fillers and scaffolds for tissue engineering. Here, we describe their current clinical use and propose a picture of their evolutions for the next 20 years. The need for tough, strong and stable bioinert ceramics should be met by either nano-structured, alumina and zirconia based ceramics and composites or by non-oxide ceramics. Nano-structured calcium phosphate ceramics and porous bioactive glasses, possibly combined with an organic phase should present the desired properties for bone substitution and tissue engineering. The position of ceramics in a gradual medical approach, from tissue regeneration to conventional implants, is discussed.

Ceramics for medical applications: A picture for the next 20 years

This review describes the mechanisms responsible for low-temperature degradation (LTD) of zirconia ceramics and its detrimental consequences for biomedical devices. Special emphasis is given to the critical issue of zirconia degradation actually observed for hip prostheses. Experimental methods to accurately measure and predict LTD in a given zirconia ceramic are presented. Different solutions to inhibit LTD or at least reduce its kinetics are reviewed, with the objective of highlighting alternative options for the generation of new zirconia-based biomedical ceramic devices.

Low-Temperature Degradation of Zirconia and Implications for Biomedical Implants

https://hal-emse.ccsd.cnrs.fr/emse-00508691/document

Laurent Gremillard

Papers

The Tetragonal-Monoclinic Transformation in Zirconia: Lessons Learned and Future Trends

Ceramics for medical applications: A picture for the next 20 years

Low-Temperature Degradation of Zirconia and Implications for Biomedical Implants

Structural transformations of bioactive glass 45S5 with thermal treatments

Influence of surface finish and residual stresses on the ageing sensitivity of biomedical grade zirconia