Ceramics have numerous uses in the field of biomaterials, mainly because of their physicochemical properties. Their chemical inertness helps to minimize organic reactions of the host organism and their hardness and resistance to abrasion makes them suitable for substitution of hard tissues (bones and teeth). Some
ceramics also have excellent tribological properties and are utilized in friction couples intended to replace malfunctioning joints. Finally, other properties (appearance, electrical insulation) also determine certain biomedical applications.
12.2.2. Multipurpose ceramics
A number of implanted ceramics have not actually been designed for specific biomedical applications and are used in different implantable systems because of their properties and their good biocompatibility.
12.2.2.1. Alumina
Alumina is one of the most widely used multipurpose ceramics. It is essentially used in orthopedics for its good tribological properties and its outstanding chemical inertia. One of the advantages of alumina is that it is a very bad substrate for the crystalline growth of calcium phosphates, which can alter other friction couples
[ROY 93]. It constitutes the heads of femoral prostheses and is used also in the development of the acetabulum. Early applications raised some problems of mechanical strength, now very rare, and led to the creation of wear debris. These problems were attributed to different causes: too large grain size of sintered piece, loosening at grain boundaries, insufficient density and shaping flaws. Today, the alumina used have evolved and most of these problems have been eliminated. Properties of alumina used have been stringently
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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