Abstract: An anchor (1) adapted to be implanted for osseo integration by the known and perfected surgical techniques, together with an intermediate transmucosal spacer member (2) for mounting a dental prosthesis (4) using an interposed post (3), the combination being such that the transmucosal spacer member and the post mounted thereon when installed, constitute in effect an axially offset extension of the anchor, the angle (37) of the offset of the post axis being variable and selectable, and the offset of the extension being adjustable as to its orientation in azimuth relative to the implanted anchor (1), prior to permanent or semi-permanent fixing, by relative rotation of parts at a bonded and preferably keyed plug and socket type connection (21) between the intermediate transmucosal spacer member (2) and one end of the anchor (1).