Outcome of oral implant treatment in partially edentulous jaws followed 20 years in clinical function

Abstract

Background: Most long-term follow-up studies of implants in partially edentulous jaws present their outcomes as mean values of implant survival and follow-up time, and few address the fate of the remaining teeth.

Purpose: The aim of this study was to investigate the results of oral implant treatment in partially edentulous jaws after 20 years, and simultaneously to assess what happens to teeth present at the time of implant placement.

Materials and methods: Seventeen partially edentulous patients, of 27 originally treated individuals, were retrospectively reviewed after receiving implants from 1983 to 1985. The parameters studied were implant survival, prosthesis stability, marginal bone loss at teeth and implants, treatment complications, need for dental treatment, and patient's satisfaction with the outcome.

Results: The cumulative survival rate was 91%, when all 27 patients were assessed, that is, including the 10 dropouts. Of the 69 inserted and followed implants (Brånemark system; Nobel Biocare AB, Göteborg, Sweden), six failed (8.7%) during the 20-year period, four during the first decade, and the remaining two during the second. A majority (n=4) of the losses were due to implant fractures, two after 8 years, and two after 17 years. In all, 10 of the original fixed bridges being followed (n=24) remained in function during the entire investigation period, whereas 12 were exchanged for new constructions after an average of 7 years. The mean marginal bone loss at teeth was 0.7 mm, and at implants it was 1.0 mm. The major complication observed during the second decade was veneer material fractures, which occurred 14 times in six patients. Component loosening and abutment- and bridge-locking screw fractures were the second most common problems seen, indicating material/component fatigue. Most patients were satisfied with their treatment and many mentioned that they did not think of the constructions as anything but a part of their own body.

Conclusion: Over the decades, treatment of partially edentulous jaws with turned titanium implants seems to function well and to provide patients with good support for fixed short-span bridge constructions.