Over a 78-month period from 1983 to 1990 at the Mayo Clinic, 353 patients involving 407 jaws were restored with 1,778 Brånemark system implants supporting prostheses. Complications involved loss of implant anchorage, soft tissue problems, or mechanical problems. The most predominant complication involved soft tissues. There were 152 patients with loaded prostheses who had no complications and 37 with only one occurrence. Those seen in 160 patients with more than one occurrence were all conservatively managed, so that prosthesis use was only permanently discontinued in 4 patients, who returned to the use of a maxillary complete denture.