الفهرس 
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Abstract
Osseouintegrated dental implants had been proved successful in total
and partial edentulous treatment cases (1-5). There is a great variety of
alternative therapeutic prostheses at hand which, for practical reasons, will be
classified as follows: Wholly or partially made of porcelain fixed prostheses,
either cemented or screw-retained. Porcelain crowns can only replace lost
teeth, bland tissues and alveolar bone (4, 6).
Implant mucous-retained overdentures. They are a simple and efficient
solution for patients with whole prosthetic stability problems. The function of
the implant is only that of retaining on the mucous rest. Two implants at least
and never more than four are necessary for their making. Fewer implants than
the totally implant supported overdenture are necessary, and the procedure of
their making is simple and cheap. They have O-ring, locator and round bars
with Hader clips, among others, kinds of attachments, which anchor the
implant to the overdenture. It is a resilient anchorage system which allows
vertical and rotary movement of the overdenture. This prosthetic design uses
bone crowns as primary holding areas. chronic occlusion pressure would
inevitably produce a progressive wearing off the alveolar bone, except for the
areas where implants are placed (4, 7).
Implant supported overdentures. Milled bar and telescopic overdentures
are under this group. The implant acts as retainer and prosthetic holder. They
present a rigid anchorage system between the implant and the overdenture,
and do not need to be held on soft tissues. Its operational biomechanism is
similar to that of fixed porcelain and hybrid prostheses. The implant
supported milled bar overdenture presents one or two milled bars that are
conically oriented from 2 to 10 grades. The overdenture, which is removable,