Abstract: A dental implant including a post which can be anchored in the jawbone of a dental patient and a replacement tooth head fastenable to said post. The post has at its crown end a recess for mounting a replacement tooth. The outside surface of the post is stepped down in at least two, and preferably three or four, steps to an apical root end opposite said crown end. At least one of the steps carries an external screw thread, and of two adjacent steps, the step closer to the apical root end has a thread crest diameter which is not larger than the base diameter of the adjacent step situated closer to the crown end of the implant.

Abstract: A knee-jount endoprosthesis including a femoral part (2), a meniscus element (6) and a tibial part (12), the femoral part (2) and the tibial part (12) lying with their bearing surfaces in contact with associated bearing surfaces of the meniscus element (6). This endoprosthesis is capable of achieving the physiological knee-joint functions of movement and load-bearing while preventing local peak stresses, especially those caused by line or point contact. The femoral part (2) is provided with a spherical bearing surface (4) which lies on a corresponding spherical and concentrically disposed bearing surface (8) of the meniscus element (6). The tibial part (12) has a convex configuration and a cylindrical bearing surface which contacts a mating, coaxially arranged second bearing surface (10) on the meniscus element (6).