http://en.wikipedia.org/wiki/Oral_implant

Oral implants are surgically placed below the gums over a series of appointments and they fuse to the jawbone and serve as a base for individual replacement teeth, bridges or a denture. Integration of the implants into your jaw also helps your replacement teeth feel more natural and some people also find the secure fit more comfortable than conventional substitutes. Research shows that implant-supported prostheses increase patient comfort. Multiple implants may be used to support a denture which will have attachments which snap or clip it into place. It will be firmly supported by the implants, stimulating the jaw and halting bone loss.