Implant Survival in the Edentulous Jaw-30 Years of Experience. Part I: A Retro-Prospective Multivariate Regression Analysis of Overall Implant Failure in 4,585 Consecutively Treated Arches.

PURPOSE

To report retro-prospective data on the prevalence of overall implant failure in a large number of edentulous patients treated at one referral clinic over a 30-year period and to analyze possible associations between implant failure and basic clinical variables.

MATERIALS AND METHODS

Altogether, 24,781 implants were consecutively placed in 4,585 edentulous arches between 1986 and 2015. All implant failures identified at the clinic during follow-up were consecutively recorded, and a multivariate logistic regression analysis was performed to identify possible associations between implant failure and different clinical factors.

RESULTS

Altogether, 1,333, 688, and 249 treated arches were followed up for 15, 20, and 25 years, respectively. Cumulative survival rates (CSR) for the treated arches were 86.2% and 83.8% after 15 and 25 years, respectively. Most patients lost only one implant each (58%). Loss of all implants was reported in 68 arches, with total failure rates of 1.9% and 2.2% after 15 and 25 years, respectively. The strongest associations with increased risk for implant failure were maxilla (hazard ratio [HR] 4.76; 95% confidence interval [CI] 3.70 to 6.25) and implant surface (HR 2.38; 95% CI 1.59 to 3.57). Age at surgery, implant surgeon, calendar year of surgery, and time of follow-up also showed significant associations with risk of implant failure (P < .05). A completely steady-state level in implant survival was not observed, but few implants were lost up to the last years of follow-up.

CONCLUSION

There is a higher risk for implant failure in the maxilla compared to the mandible. Risk is reduced when using implants with a moderately rough surface. The highest risk for failure was observed during the first year. This was followed by a reduced failure rate, which never reached a steady-state level.