SURVIVAL ANALYSIS OF ENDOSSEOUS IMPLANTS IN BONE-GRAFTS USED FOR THE TREATMENT OF SEVERE ALVEOLAR RIDGE ATROPHY

Purpose: The aim of the current study was to evaluate the long-term re sults of endosseous implants placed into autogenous bone grafts in sev erely atrophic alveolar ridges. Patients and Methods: A total of 871 i mplants were placed in 137 patients. The success rate was determined u sing survival analysis, log rank tests, and a cox regression analysis. Results: Seventy-four implant failures were encountered in 23 patient s, Most implants were lost because of a lack of osseointegration at th e time of abutment connection or by asymptomatic loosening during the first months thereafter. The overall 1-year cumulative survival rate ( CSR) was 83.4%, with a decrease to 67.8% after 5 years, The only param eter of prognostic relevance in the multivariate analysis of the whole study population was the patients' gender, with a significantly worse prognosis in female patients (5-year CSR, 62.3%), However, when the p atients were divided into edentulous and partially edentulous jaws, a change was observed in the overall significance of the parameters intr oduced into the analysis, In edentulous patients, the maxilla appeared to overrule all other parameters, with a 5-year cumulative survival r ate of 48.8%, whereas the mandible presented a significantly higher ra te of implant survival (5-year CSR, 89.3%). Conclusion: This study sho ws a poorer success rate in females than in males, probably because of differences in the quality of the bone grafts.