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Bioactive ceramics

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الكلية كلية هندسة المواد     القسم قسم البوليمرات والصناعات البتروكيمياوية     المرحلة 3
أستاذ المادة اسراء قحطان صبري محمد       15/12/2014 08:42:32
Bioactive Ceramics
Bioactive ceramic is a general term covering bioactive glasses, glass-ceramics and hydroxyapatite. They exhibit a positive reaction at the interface between the host tissue and the implant in the biological environment resulting in bonding, each with varying ability according to its type. the level of bioactivity has been related to the physiological process of bone formation via an index of bioactivity that relate to the amount of time it takes for 50 percent of the interface to be bonded:
Bioactivity Index, IB = 100/t0.5bb
Where (t0.5bb) is the time taken for more than 50% of the interface to bond to bone. According to the Bioactivity Index, bioactive materials can classify into two types as listed below:
• Bioactive materials class A: materials exhibiting an IB value greater than 8, they are actively interacting with tissues and induce their intrinsic repair and regenerative as well as bond to both soft and hard tissue e.g. the bioactive glass and glass-ceramic.
• Bioactive materials class B: materials with an IB less than 8 but greater than 0, they are considered only as osteoconductive materials, e.g. Synthetic hydroxyapatite (HA) which has chemical similarity to bone and good biocompatibility, and tri-calcium phosphate (?-TCP) .
It is important to know that the nature of biomaterial- tissue interface and the reactions (e.g. ion exchange) at the ceramic surface and in the tissues dictate the resulting mechanical, chemical, physical, and biological process that occur. In general four factors determine the long term effect of bioactive ceramic implants: (1) the site of the implantation, (2) tissue trauma, (3) the bulk and the surface properties of the material, and (4) the relative motion at the implant-tissue interface.

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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