Survival analysis of implants placed simultaneously with lateral sinus floor elevation in severely atrophic maxilla: A 3-to 12-year retrospective cohort study

ObjectivesTo retrospectively evaluate whether implants placed simultaneously with lateral sinus floor elevation (LSFE) in severely atrophic maxilla (residual bone height [RBH] & LE;3 mm) could achieve long-term survival and comprehensively analyze the factors influencing their survival rates. Materials and MethodsA total of 123 patients receiving LSFE and simultaneous implant placement from 2010 to 2019 and their 123 implants in sites with RBH & LE;3 mm were included in this study. Basic characteristics of patients and implants were collected from the medical record system and cone-beam computed tomography (CBCT) images. Kaplan-Meier survival curves were applied to estimate cumulative survival rates (CSRs) and Cox proportional hazards regression models were used to detect factors influencing implant survival. ResultsThe 6-year and 12-year CSR of implants placed in sites with RBH & LE;3 mm were 95.7% (95% confidence interval [CI]: 92.1%-99.5%) and 76.6% (95% CI: 58.1%-100%), respectively. Eight patients presented late implant failure. Univariate and multivariate Cox regression analyses demonstrated that RBH & LE;2 mm (hazard ratio [HR]: 20.63, p = 0.000) and smoking habit (HR: 6.055, p = 0.024) were significantly associated with long-term implant survival. Specifically, the 10-year CSR of implants in sites with RBH & LE;2 mm (53.3%, 95% CI: 27.5%-100%) was dramatically lower than those in sites with RBH >2 mm (92.9%, 95% CI: 81.7%-100%, p = 0.000). ConclusionsImplants placed simultaneously with LSFE in sites with RBH & LE;3 mm can achieve long-term survival. However, caution is required especially for implantation in sites with RBH & LE;2 mm. Besides, the smoking habit is also considered a risk factor jeopardizing long-term implant survival.