Predicting clustered dental implant survival using frailty methods

J Dent Res. 2006 Dec;85(12):1147-51. doi: 10.1177/154405910608501216.


The purpose of this study was to predict future implant survival using information on risk factors and on the survival status of an individual's existing implant(s). We considered a retrospective cohort study with 677 individuals having 2349 implants placed. We proposed to predict the survival probabilities using the Cox proportional hazards frailty model, with three important risk factors: smoking status, timing of placement, and implant staging. For a non-smoking individual with 2 implants placed, an immediate implant and in one stage, the marginal probability that 1 implant would survive 12 months was 85.8% (95%CI: 77%, 91.7%), and the predicted joint probability of surviving for 12 months was 75.1% (95%CI: 62.1%, 84.7%). If 1 implant was placed earlier and had survived for 12 months, then the second implant had an 87.5% (95%CI: 80.3%, 92.4%) chance of surviving 12 months. Such conditional and joint predictions can assist in clinical decision-making for individuals.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Cluster Analysis
  • Cohort Studies
  • Dental Implantation, Endosseous / statistics & numerical data
  • Dental Implants / statistics & numerical data*
  • Forecasting
  • Humans
  • Proportional Hazards Models
  • Retrospective Studies
  • Risk Factors
  • Smoking
  • Survival Analysis
  • Time Factors


  • Dental Implants