How does the placement of a Subperiosteal Implant differ structurally from an Endosteal Implant regarding bone contact?

Rests on top of the jawbone beneath the gum tissue.

The fundamental difference between Subperiosteal and Endosteal implants lies in their relationship with the jawbone. Endosteal implants require placement directly into the bone structure itself to achieve osseointegration. Conversely, Subperiosteal implants are designed for patients with severe bone loss where direct insertion is impossible or inadvisable. These historical implants consist of a custom-fabricated metal framework that is seated directly onto the existing surface of the jawbone, positioned just beneath the overlying gum tissue. Posts then protrude through the gum to anchor the prosthetic, but stability is derived only from the surrounding soft tissue, not a direct integration with the bone mass, which generally results in lower long-term security compared to modern methods.