[Bone-anchored implants: comparison of the techniques and values of endo- and juxta-bone implants].

Extra-oral implants have been used for well-defined application for nearly 20 years; for tupoorting maxillo-facial prostheses and for bone anchored hearing aids (BAHA). In both of these applications, the bone-anchored prostheses support transcutaneous abutments. It is the junction between the implant and the abutment which ensures, given certain preconditions, the permanent percutaneous connection (PPC). The authors describe the two types of implants currently in use-intra- and juxta-osseous implants. They then give a brief description of the two techniques. The advantages and disadvantages of each system are summarised, as well as the conditions required for permanent survival of a PPC.