Prevalence of Implant Loss and the Influence of Associated Factors

Background: The objective of this study was to assess the outcome of dental implants inserted at the Institute of Clinical Odontology, University of Oslo, between 1990 and 2005. The prevalence of implant loss and the factors associated with the outcome were studied. Methods: A total of 164 subjects were invited to participate in this cross-sectional project, of whom 55 were unable, leaving 109 volunteers available for examination. The study population included 69 females and 40 males with a mean age of 43.8 years at the time of implant insertion (range, 18 to 80 years). At the subject level, the mean time from implant loading to the present examination was 8.4 years (range, 1.1 to 16.0 years). The participants were examined clinically and radiographically and interviewed regarding general health and habits. Results: The 109 examined subjects had been treated with 374 implants. Eighteen implants (4.8%) were lost in 10 subjects (9.2%). Eleven implants were lost before loading, three were lost during the first 5 years after loading, and four were lost 5 to 10 years after loading. No implants were lost after >10 years of loading. The loss of oral implants was significantly associated with a history of smoking and periodontitis (P<0.05). Conclusions: The inserted implants showed a high survival rate, especially after the first year of insertion, even though the subjects were not maintained by specialists. All late implant losses were preceded by an early loss. Implant loss was significantly associated with smoking and periodontitis. J Periodontol 2009;80:1069-1075.