Not just wisdom teeth can be "impacted" (under the gum or imbedded in the bone). Some patients present from the orthodontist with a request to "uncover and bond an attachment" to an impacted tooth. This is usually an upper canine tooth (third back from the middle). The uncover part means that the surgeon is to locate the crown of the tooth, and this involves exposing it surgically. This is routinely done in my office with either general anesthesia or a deep sedation. During the procedure, an orthodontic button is attached—bonded—with a very strong adhesive to the crown of the tooth. There is a very fine gold chain attached to this bonded button, and that extends down and is attached loosely during the surgery to a tooth close-by. It is this gold chain that the orthodontist will use to slowly move your tooth into the correct position.
So when the surgeon finishes the procedure exposing it, your tooth will be in the same position but will now have an attachment on it that the orthodontist will use to apply light rubber band traction to at your next ortho appointment (days or weeks later). It is this light rubber band tugging that will move your tooth! This can achieve amazing results, but can take up to six months or longer to accomplish. The orthodontist usually will apply "traction" to your chain within two weeks after the tooth is uncovered, but some prefer to move ahead even sooner.
Movement of teeth is best accomplished in younger patients. Although movement of impacted teeth can be done into your twenties and older, it does become more difficult and less predictable as we get older.