| 摘要 |
<p>The implant body is formed by a cylindrical tube (11) with a central passage (15) formed longitudinally into its solid upper portion. The passage has at least two coaxial internal threaded surfaces, the lower one (19) being of lesser diameter than the other (18). The upper end of the passage is defined by a portion of polygonal cross-section (20) of greater diameter than the upper threaded portion. The head of the implant may be formed with a threaded portion (102) which engages the upper threaded surface of the passage, or with a polygonal projection (202) which engages the polygonal portion of the passage.</p> |
