Long-Term Clinical Evaluation of Short Implants on Posterior Partially Edentulous Areas: A 14-Year Retrospective Study

Purpose The clinical long-term outcomes of short implants are controversial. The aim of this study was to perform a long-term evaluation of short implants in posterior partially edentulous areas under various conditions. Materials and methods This retrospective study was conducted with patients who had received 5- to 8-mm short implants to avoid bone grafts and spare anatomical structures between November 2005 and February 2014. Clinical outcomes (primary and secondary stability, marginal bone loss, and success and survival rates) were analyzed according to predictor variables of surgical procedure (submerged vs nonsubmerged), crown/implant ratio (1.5 and 2.0), type of prosthetic (single vs splinted crown), and arch location (maxilla vs mandible). The success rate was evaluated according to Albrektsson's criteria, and 5- and 10-year cumulative survival rates were calculated using Kaplan-Meier survival curves. Results A total of 148 patients (73 men, 75 women, mean age: 59.2 years) and 225 short implants were analyzed in this study. Over an average period of 6.21 ± 3.09 years, marginal bone loss was 0.43 ± 1.01 mm, and overall success and survival rates were 93.33% ± 25.0% and 97.78% ± 14.77%, respectively. Cumulative 5- and 10-year survival rates were 99.05% ± 0.65% and 96.72% ± 1.62%, respectively. Conclusion Short implants (≤ 8 mm) in posterior edentulous areas showed comparable long-term outcomes of marginal bone loss and success and survival rates with conventional implants regardless of other clinical variables such as surgical procedure, crown/implant ratio, prosthetic type, and arch location.