Sargon Barkarmo and Jan Kowar of the University of Gothenburg analyzed the long-term outcomes of single-tooth implants in a small group of patients and found that the vast majority continue to function decades later. The analysis included 13 patients who received 18 single implants at the Brønemark Clinic between 1982 and 1985. They underwent clinical and radiographic examinations 38 to 40 years later. The results were published in the journal Clinical Implant Dentistry and Related Research.
The cumulative survival rate of implants was 95.6 percent, and that of crowns installed on them was 60.9 percent (replacement was necessary for aesthetic reasons). Changes in marginal bone level were acceptable. The average pocket depth on probing was 3.8 ± 2.2 millimeters (with a normal range of up to 3.0). The incidence of technical and biological complications was low, with mucositis being the most common, and no cases of peri-implantitis were reported.