Comparing factors affecting dental-implant loss between age groups: A retrospective cohort study.

BACKGROUND: There is a growing interest in factors leading to implant failure in older people as the population aged 65 years or older continues to expand. PURPOSE: We sought to identify differences of results in the implant survival rate and the influence of certain factors on implant failure in the older (>/=65 years) and younger (<65 years) patients. MATERIALS AND METHODS: Patients who underwent their first dental-implant surgery between July 2008 and June 2018 were included. Data on age, sex, smoking habits, medical conditions, implant location, implant size, and the presence and type of bone graft and membrane were collected and analyzed according to age group. Moreover, cumulative survival rates of implants (by Kaplan-Meier analysis) and hazard ratios (HR) of each factor (using Cox regression analysis with shared frailty) in each group were assessed and results compared between groups. RESULTS: A total of 628 implants in 308 patients and 1904 implants in 987 patients in the older and younger groups, respectively, were assessed, with failure rates of 3.9% and 3.4%. Per Kaplan-Meier analysis, the 11-year patient-level cumulative survival rate of implant treatment was 95.3% (95% CI: 0.91-0.97) in the older and 93.9% (95% CI: 0.88-0.97) in the younger group. The HR for implant failure of the variables, except diameter of dental implants, were not statistically significant in both groups. CONCLUSION: The outcomes of implant treatment were not considerably different between the age groups.