[Research for the influencing factors affecting the long-term survival time of implants: a retrospective cohort...

To investigate the timing of implant failure events and their relationship with the dental position and the factors affecting the survival time of implants.

A retrospective cohort study was conducted to analyze the patients who had implants removed due to implant failure in the Department of Dental Implantology of Hefei Stomatological Hospital from January 2019 to December 2021. The predictor variables were surgical age, gender, smoking habit, oral hygiene, glucose value, jaw and dental position, implant type, implant number, surgeon, implant placement timing, implant loading timing, and antibiotic use timing. The outcome measurement was the implant survival time and implant failure events. Chi-square test, Kaplan-Meier(Log-rank test), and Cox proportional hazards model were used to identify and stepwise determined potential risk factors for implant survival time with SPSS 21.0 software package.

A total of 89 patients(95 implants) had to remove implants. The mean survival time of the failed implants was 31(95%CI :24.2-39.1) months. Implant number (P=0.038), implant loading timing (P=0.050), and tooth position (P=0.024) were significantly correlated with the implant survival time. The risk of failure with 2 implants was 2.709 (HR=3.709, 95%CI: 1.075-12.795) times higher than that with 1 implant, and the risk of failure with late implant loading was 0.551(HR=1.511, 95%CI: 0.999-2.406) times higher than that with early implant loading. The risk of anterior teeth implant failure was 1.384 times higher than that of molars(HR=2.384, 95%CI:1.327-4.283). For patients with implant failure, about 50% of the patients removed the failed implant within 1 year after surgery, and the rate of removal of the failed implant gradually slowed down in the following 2-10 years. Peri-implantitis most commonly occurred in molars(50%). Implant fracture lastly occurred at 55(95%CI: 42.2-67.9) months postoperatively（P=0.000）.

The number of implants, implant loading timing, and dental position were considered as the influencing factors for the survival time of implants. Follow-up in the first year after implantation seems to be particularly important for timely detection of problems and timely intervention. The occurrence of implant failure events was related to dental position and time.