Aim: To compare the 3-year clinical, radiographic and economic outcomes of short-6-mm implants and longer implants combined with osteotome sinus floor elevation (OSFE) in the posterior maxilla. Material and Methods:This study enrolled 225 patients (225 implants with diameter of 4.1 mm and 4.8 mm) with a posterior maxillary residual bone height (RBH) of 6-8 mm. Patients were randomly divided into three groups: Group 1 (6 mm implants alone), Group 2 (8 mm implants + OSFE) and Group 3 (10 mm implants + OSFE). The following outcomes were recorded at 1 and 3-year examinations: implant survival, probing pocket depth (PPD), bleeding on probing (BOP), modified plaque index (mPI), marginal bone loss (MBL), biological and technical complications, complication-free survival and treatment costs.Results: At the 3-year follow-up, 199 patients (Group 1: 67; Group 2: 62; Group 3: 70) were re-examined. Implant survival rates were 91.80%, 97.08% and 100.00% in groups 1, 2 and 3. Implant survival rate in Group 1 was significantly lower than that in Group 3 (p = 0.029). A multivariate Cox model showed that the short-6-mm implants with wide diameter had a protective effect on implant survival (hazard ratio: 0.59, p = 0.001). No significant differences in BOP%, PPD, mPI, MBL and complication-free survival rate were found among the three groups. The average costs of retreatment were 8.31%, 1.96% and 0.56% of the total costs in groups 1, 2 and 3. The cost to avoid a 1% increase in implant loss associated with 6-mm implants over a 3-year period was 369 CNY (56 USD) using a 10-mm implant with OSFE and 484 CNY (74 USD) using an 8-mm implant with OSFE. Conclusion:In the moderately atrophic posterior maxillae, the three treatments showed acceptable clinical, radiographic and economic outcomes with up to 3-year follow-up. 10-mm implants combined with OSFE showed more favourable implant

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.