Implant with a removable superstructure. Cobalt/chromium casting that is inserted between the periosteum and the bone to support a denture.
The first subperiosteal implant was placed by Dahl in Sweden in 1943 and this technique was employed until the early 1980s. The technique was slowly discontinued and replaced by blade-vent implants and subsequently by endosseous implants.
This technique provided additional support and retention in an atrophic ridge situation. Whilst the implants had a reasonable success rate at five years it dropped dramatically after this period.
• The technique involved the taking of an impression of the underlying bone, necessitating a surgical procedure, and a subsequent procedure to place the metal casting.
• Bone resorption progressed and therefore these frameworks soon no longer fitted the underlying bone
• Commonly infections tracked down the implant post causing infections in the underlying bone and exposure of the metal casting.
1. A surgical procedure was carried out to expose the bone and an impression of this was made.
2. This was then used to cast a cobalt/chromium framework which was placed under the periostium; sometimes anchorage screws were placed to secure it to the underlying bone. This was allowed to heal and a casting which had previously been made to fit the implant posts was incorporated into the denture base.