aim: to compare the accuracy of the conventional and digital impression when will be performed on implant level or abutment level in Complete digital workflow for construction of full arch implant supported screw-retained restoration.

The patient will be selected according to the following criteria:

1. Free from any systemic disease that may interfere with proper Osseointegration of implants, which will be assessed by thorough medical investigations.
2. Patients having completely edentulous maxilla and mandible for at least 6 months after the last extraction.
3. Normal maxilla mandibular relationship with adequate inter-arch space, measured by tentative jaw relation.
4. Sufficient residual alveolar ridge.

Exclusion criteria include:

1. Local or general contraindications for surgical procedures.

2. Patients with TMJ disorders or poor neuromuscular coordination or parafunctional habits.

3. Severe inter-maxillary skeletal discrepancy or limited inter-arch space.

4. Heavy smokers.

   • For all patients, conventional complete dentures are constructed.
   • Implants installed in the edentulous maxilla and mandible in each target position guided by stereolithographic stent. A delayed loading protocol is followed in this study.
   • After osseointegration, a conventional open tray splinted impression technique will be made for each patient on the implant/abutment level.
   • Scan bodies' implant level/abutment level will be tightened for each patient, and a digital intraoral scanner will be used to scan the scan bodies for making implant level/abutment level digital impressions.

Accuracy will be evaluated as follows:

• 3D inspection software using the best-fit alignment algorithm will be utilized to calculate the 3D deviation of each impression using the root mean square (RMS) error.
• Passive fit of the framework will be evaluated at the time of insertion.

Inclusion Criteria:

• Free from any systemic disease that may interfere with proper Osseointegration of implants, which will be assessed by thorough medical investigations.
• Patients having completely edentulous maxilla and mandible for at least 6 months after the last extraction.
• Normal maxilla mandibular relationship with adequate inter-arch space as verified by tentative jaw relation.
• Sufficient residual alveolar ridge.

Exclusion Criteria:

• Local or general contraindications for surgical procedures.
• Patients with TMJ disorders or poor neuromuscular coordination or parafunctional habits.
• Severe inter-maxillary skeletal discrepancy or limited inter-arch space.
• Heavy smokers.