 1. To evaluate and compare the cumulative survival rate CSR of the NobelReplaceTM CC implants supporting NobelProceraTM Implant Bar Overdenture fixed-removable in the mandible with the cumulative survival rate CSR of the NobelReplaceTM CC implants supporting NobelProceraTM Implant Bar Overdenture fixed-removable in the maxilla for a period of 5 years. 