Abstract: PURPOSE: To evaluate the clinical efficacy of immediate replantation using simple taper fixed implants at failed implantation sites. METHODS: Patients with implant failure at the Department of Stomatology, Fourth Affiliated Hospital of Nanchang University from January 2018 to December 2022 were collected. Simple taper-retained implants were used for immediate replantation at implant failure sites. Marginal bone loss, survival rate and complications were analyzed at immediate replantation(T0), immediately after repair(T1), and at the last follow-up(T2). RESULTS: A total of 33 implantation failure sites in 31 patients were included at an average of (13.27±21.92) months after primary implantation, 33.33% were early failures and 66.67% were late failures; the average follow-up after immediate reimplantation was (14.22±9.90) months, with an overall retention rate of 100%. History of periodontitis, smoking, systemic diseases, and nocturnal grinding conditions, occlusal relationship, and bone type at the implant site had no significant difference in the effect of peri-implant marginal bone resorption; the difference between the mean implant length and the implant length at primary implantation was not statistically significant, but there was significant difference in the implant diameter and implantation depth between the primary implantation and the reimplantation. Binary Logistic regression model showed that the diameter of the implant had no significant effect on the survival rate of the implant, but the deeper the implant depth, the higher the survival rate of the implant.There was significant bucco-lateral bone height resorption at T0 and T1, but no significant changes in proximal and distal mesial heights, lingual bone heights, and buccolingual bone thickness at T0, T1, and T2. Buccolingual lateral bone height had the least amount of resorption in the T2-T1 period, which was statistically different from the amount of bone resorption in the T1-T0 and T2-T0 periods. Buccolingual lateral bone thickness was statistically different from the amount of bone change in the T1-T0 and T2-T1 periods, but there was no significant change in proximal and distal mesial heights, buccolingual lateral bone heights, and lingual lateral bone thicknesses in the T1-T0, T2-T1, and T2-T0 periods. CONCLUSIONS: The application of simple taper fixed implant system for immediate replantation at failed implant sites has good short-term clinical effects, and immediate replantation can be considered in the event of implant failure.

Key words: Oral implant failure, Immediate reimplantation, Simple taper-retained implants, Survival rate