Influence of implant length and diameter on implant failure: A retrospective study

Objective: Dental implants are widely accepted in the dental community. Although several studies have reported high dental implant survival rates, complications can still occur. Implant failure is associated with different risk factors, including implant length and diameter. However, no clear consensus has yet been reached. This study aimed to evaluate the influence of different risk factors associated with implant failure. Methods: This study included patients who received dental implants at Kyoto University Hospital. The inclusion criteria were dental implants placed between January 1, 2005 and December 31, 2022. Data on patient- and implant-related variables were collected. We used a marginal Cox proportional hazards models to investigate the association between the potential factors and implant failure. Results: This study included 147 patients who received 479 dental implants. Eleven of the 147 patients experienced implant failure, whereas 17 of the 479 implants failed. The cumulative survival rate of dental implants at the final time point was 95.3%. Multivariable marginal Cox analysis showed suggestive evidence that implant length (<10 mm) greatly increased the risk of implant failure compared with implant length (>= 10 mm) (reference: <10 mm, hazard ratio, 0.07; 95% confidence interval, 0.01-0.34; p = 0.001). Conclusions: A cumulative survival rate comparable to that reported in other studies was achieved over prolonged periods of time. Although implant failure is multifactorial and implant length is only one of many factors contributing to implant loss, clinicians must be aware of the potential influence of implant length and make treatment decisions.