Long-term clinical outcomes of short implant (6mm) in relation to Implant Disease Risk Assessment (IDRA)

Aim To evaluate the long-term survival of short implants and to investigate the association of the Implant Disease Risk Assessment (IDRA) with the occurrence of biological complications. Material and Methods This study was designed as a cohort study with a median follow-up of 10.0 years. Patients who had received 6-mm implants were reviewed and assigned into low-, moderate-, and high-risk groups (Group L, M, and H) based on the IDRA tool. The implant survival, biological complications, soft tissue condition, hardware complications, and marginal bone loss (MBL) were evaluated. Kaplan-Meier curves and Cox regression were performed for survival analysis. Results A hundred and ten patients were included. The overall cumulative survival rate was 90.9% (L:100.0%, M: 93.3%, and H: 80.6%). A higher risk profile was significantly associated with a decreased implant survival (hazard ratio: 4.11, 95% CI: 1.17-14.36, p < .05). Higher risk profile (hazard ratio: 2.63, 95% CI: 1.32-5.25, p < .05) was a potential risk factor for biological complications. At follow-up, significant differences in bleeding index, modified plaque index, and peri-implant probing depth were found among groups (p < .01). No significant difference was found in MBL. Conclusion Acceptable long-term clinical outcomes could be achieved after 10 years for short implants. Despite a statistically nonsignificant difference in MBL, patients with a high-risk profile of IDRA seem to be at greater risk of implant loss and biological complications.