There are 2 categories of dental implants: Those that are placed into the jaw-bone and those that rest on top of the jaw-bone.
An endosteal implant is placed directly into the bone, just like a natural tooth root and can be used for various purposes. A single pin can be inserted through an existing tooth to strengthen and stabilize it. Other styles can provide an anchor for one or more artificial teeth.
A subperiosteal implant is used when the bone has atrophied and jaw structure is limited. The lightweight, individually-designed, metal framework fits over the remaining bone, providing the equivalent of multiple tooth roots. This may be used in a limited area or, if all the teeth are missing in the entire mouth.
The amount and location of available bone determine the kind of implant that is best to use. Natural tissue membrane or bone will grow back around either implants making it even more secure.