the study is concerned with assessing retrospectively the survival and complication rates of monolithic zirconia implant-supported fixed full arch dental restoration scanned using scan ladder scan body over a follow-up period of 1 year.

Inclusion Criteria:

• - Any completely edentulous patient (mandible) with an old satisfactory denture requiring an implant-supported restoration.
• Patients aged from 40 to 70, able to sign an informed consent will be considered eligible for this trial.
• Implant sites must allow the placement of four implants.
• Non- heavy Smokers will be included (smoking up to 10 cigarettes/day)
• In case of post-extractive sites, they must have been healed for at least 3-month before being treated in the study.
• Patients with no systemic condition that may interfere with implant placement (e.g., Immunosuppressed or immunocompromised patients, patients under treatment of intravenous amino-bisphosphonates)

Exclusion Criteria:

• - Patients with poor oral hygiene and motivation.
• Pregnancy or nursing.
• Drug abusers.
• Psychiatric problems or unrealistic expectations.
• Patients with infection and or inflammation in the area intended for implant placement.
• Patients participating in other studies, if the present protocol cannot be properly adhered to.
• Patients with signs of hyperactive muscles.