Eighteen patients will be selected from the outpatient clinic of the Prosthodontic Department, Faculty of Dentistry, Mansoura University seeking prosthetic rehabilitation.

patients will be randomly divided into three groups according to the framework materials: PEEK, Soft metal, and selective laser melting construction.

All patients will receive conventional maxillary and mandibular complete dentures.

2. The mandibular denture will be modified by shortening the flanges and cutting the posterior part till the 1st molar then 3D scanned for recording the correct dimension of each tooth to be concerned during the construction of the superstructure and the final prosthesis.

3. Abutment level impression will be made, and the resultant cast will be 3D scanned for CAD/CAM construction of superstructure with abutments.

4. patients will be randomly divided into three groups according to the framework materials: PEEK, Soft metal, and selective laser melting construction.

5. The fit of the framework will be verified intraorally, and the final prosthesis will be digitally constructed; according to the dimensions of the scanned denture; to fit over the framework.

Evaluation Radiographic evaluation of circumferential bone level around implants and bone changes in the posterior mandible will be done using CBCT at one, two, three, and five years after insertion of the final prosthesis.

Inclusion Criteria:

• Completely edentulous maxillary ridges and mandibular arch with four implants placed according to the All-on-4 distribution. All patients were recruited from the previous study.
• All selected patients will be with sufficient inter-arch space and restorative space.
• All selected patients will have healthy ridges covered by the compressible oral mucosa and free from any ridge flabbiness.

Exclusion Criteria:

• History of para-functional habits (Bruxism, clenching), smoking, and alcoholism.
• History of radiation therapy in the head and neck region.