When thinking or talking about implants, in most cases the tacit assumption will be that it is all about restorative dentistry and dental implants. However, the term ‘implant’ is much broader than that particular application; it refers to any kind of support (literally) for prostheses of all kinds.
An implant is a device that is anchored into bone (osseointegrated) to provide strong and durable support for whatever will be attached to it. The typical construction consists of a small but strong screw (to connect to the supporting bone) with a head that connects to some intermediate construction that provides the connection and link to the (external) prosthesis. Depending on the kind of prosthesis, the prosthesis may be fixed and permanently connected (common for dental crowns, for example) or may be detachable (common for many other prostheses, for example an artificial ear).
Given the fundamental role of bony structures to carry and support implants and prostheses, an important and common part of this kind of reconstructive work is the surgical preparation (or initial repair and/or augmentation) of the bone(s) that will serve as the structural support for implants and prostheses and the surrounding soft tissues.
The aspect of surgery derives from older techniques which pre-dated successful implantology and was known as pre-prosthetic surgery. It can be used alone, in some instances, to prepare the denture fitting areas of the jaws for conventional prosthesis or as an adjunct to dental or sometimes craniofacial implants.