The introduction of a chemically inert foreign body in a living organism gives rise to a series of reactions leading to the formation of a fibrous encapsulating tissue. This fibrous tissue isolates the foreign body which could not be destroyed and
ensures at the same time the joining between the healthy tissue and the implant. This primary form of biointegration of the implant is considered to be of relatively poor quality, notably for the bone tissue where this layer allows a relative mobility of the implant and the existence of micro movements, eventually associated with the
phenomena of abrasion and with an inflammatory process. The existence of micro movements increases the thickness of the encapsulating fibrous layer . Movements of low amplitude (less than 50 micrometers) do not appear to have any effect. Above 200 micrometers, on the contrary, we observe the formation of a thick fibrous tissue. Other than the surgical skill, various morphological factors especially determine the mechanical anchoring of the implant: a porous or rough surface favors mechanical stabilization of the implant. Likewise, partially biodegradable surfaces resorbed in an irregular manner may be considered as favorable to mechanical integration.
12.3.1.2. Ceramic-tissue bonding
The integration of the implant can also be ensured by the interactions of a physicochemical nature with the tissue. These phenomena have been more particularly studied for ceramics used in orthopedics. Interactions with the mineral part have been more particularly described; those with the collagenic part of the bone are not known, despite the fact that they may play an equally important role. In the case of implants of apatitic structure, it has been shown by high resolution electron microscopy that there exists a continuity between apatite crystals of ceramics and those of bone tissues [BON 91]. These interactions of epidictic type
justify in some measure the use by apatites as orthopedic biomaterials. With other types of non-apatitic materials, even other amorphous materials such as bioglasses,
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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