Immediate dental implants: insights into early and late failures from a large-scale Chinese cohort

Immediate implant placement (IIP) has emerged as a time-efficient therapeutic approach in dentistry, offering advantages such as reduced treatment duration and improved alveolar bone preservation. However, concerns remain regarding early and late implant failures, and large-scale data on factors associated with IIP failure in Chinese populations are limited. This retrospective observational study aims to identify the factors associated with early and late failure of immediate dental implant.

Patients who underwent immediate implantation at the Second Department of Implantology, Xiamen Stomatological Hospital, between January 2013 to December 2022, were retrospectively included. Cumulative survival rates (CSR) at the implant and patient levels were calculated using the life table method and presented with Kaplan-Meier survival curves. Cox regression analysis was performed to evaluate associations between implant failure and demographic, anatomical, surgical, and implant related variables.

A total of 1513 implants placed in 781 patients were included. Of these, 50 experienced early failure and 36 experienced late failure. The 10-year CSR at implant level was 93.15% and at patient level 89.46%. Mean survival time was 47.34 ± 34.98 months (range 0-128 months). The mean patient age was 53.02 ± 14.02 years, comprising 46.46% females and 53.54% males. Multivariable analysis showed that male sex (HR = 2.48; 95% CI: 1.31-4.69), maxillary sinus elevation (HR = 2.49; 95% CI: 1.05-5.87), maxillary anterior implant position (HR = 3.15; 95% CI: 1.29-7.69), and maxillary posterior implant position (HR = 2.75; 95% CI: 1.08-6.98) were associated with higher rates of early implant failure, whereas submerged healing was associated with a lower rate of early failure (HR = 0.53; 95% CI: 0.30-0.95). For late implant failure, bone grafting without membrane coverage was associated with increased failure (HR = 3.54; 95% CI: 1.07-11.74), whereas implant diameter of 4.0-4.5 mm was associated with lower late failure compared with ≤ 3.75 mm implants (HR = 0.30; 95% CI: 0.13-0.69).

In this large retrospective cohort of Chinese patients, IIP demonstrated favorable long-term survival. Several patient-related and surgical variables were associated with implant failure; however, causal inferences cannot be drawn due to the observational study design.