Implant Failure And Associated Risk Indicators: A Retrospective Study

Objectives To evaluate early and late implant loss rates in a sample of patients who had received implant therapy in a university setting as well as patient- and implant-related variables for implant failure.Material and methods This is a retrospective analysis in a cohort of patients who were treated with implant-supported restorative therapy during the period 2001-2012. Patients were randomly selected from an electronic database and scheduled for an appointment to record subject and implant characteristics. The primary study outcome was implant loss (i.e., early and late implant failure).Results A total of 190 patients and 710 implants were included. The mean time in function was 8.2 (SD 2.4) years. Four implants (0.6%) failed in four patients (2.1%) prior to connection of the restoration within a mean period of 1.5 (SD 1.3) months after surgical procedure. Moreover, 17 subjects (8.9%) exhibited late implant failure, representing 26 implants (3.7%), after a mean follow-up of 5 years (SD 2.2) from prosthesis connection. The final multivariable model indicated three factors related to late implant failure: subjects <55 years (OR = 3.62; 95% CI 1.46-10.22; p = .002), smokers/former smokers (OR = 6.25; 95% CI 1.70-17.52; p = .005), and implants with no access to interproximal hygiene (OR = 7.25; 95% CI 2.20-28.25; p < .001).Conclusions The rate for early and late implant failure in a sample of 190 patients who had received implant therapy in a university setting was 2.1% and 8.9%, respectively, at subject level. Subjects <55 years and smokers/former smokers as well as implants with inadequate access to interproximal hygiene were significantly associated with late implant failure.