CAD/CAM (computer aided design/ computer aided manufacturing) constructed screw retained implant supported frameworks give solutions for the problems arising from the lost wax technique by improving accuracy, adaptation and passive fit of the final restoration. However, concerns about the passive fit of a pre-implant insertion CAD/CAM constructed framework still exists due to the expected errors in imaging, registration, surgical guide construction, adaptation and hence transferring the planned position intra-orally.

9. PICO Format: Population: mandibular free end saddle requiring 2 implants. Intervention: Digitally fabricated screw-mented retained metal frameworks constructed before implant placement Control: Digitally fabricated screw retained metal frameworks constructed after implant placement

Outcome:

Outcome Measuring device Measuring unit Passive fit One screw test Binary 13 Screw resistance Binary Radiographic ( digital periapical radiography) Binary III. Methods A) Participants, interventions & outcomes 9. Study settings: i. The study will be conducted at Department of Oral Implantology, faculty of oral and dental medicine, Cairo University, Egypt. ii. Participants will be selected from the outpatient clinic of implantology department, faculty of oral and dental medicine, Cairo University, Egypt. 10. Eligibility criteria: A-Inclusion criteria: i- Mandibular Kenndy Class I. ii- Opposing completely dentulous, fully or partially restored dentition. iii- Good oral hygiene. iv- The patient should have bone for implants, minimum bone height 10 mm and minimum bone diameter should be 6 mm. v- Adequate inter arch space for restoration 15mm or more. vi- Adult patients age ≥18 years B- Exclusion criteria: i. any medical disorder that could complicate surgical phase or affect osteointegration. Radiation chemotherapy. ii. smokers more than 10/daily. iii. Uncooperative patients. iv. Patients with Para-functional habits v. Patients with severe periodontal diseases. vi. Patients with limited mouth opening. vii. Presence of intraoral pathological lesions. viii. Diabetic (HbA1c >7.5%).

.Inclusion Criteria:

• Mandibular Kenndy Class I.
• Opposing completely dentulous, fully or partially restored dentition.
• Good oral hygiene.
• The patient should have bone for implants, minimum bone height 10 mm and minimum bone diameter should be 6 mm.
• Adequate inter arch space for restoration 15 mm or more.
• Adult patients age ≥18 years

Exclusion Criteria:

• - . any medical disorder that could complicate surgical phase or affect osteointegration. Radiation chemotherapy.
• ii. smokers more than 10/daily.
• iii. Uncooperative patients.
• iv. Patients with Para-functional habits
• v. Patients with severe periodontal diseases.
• vi. Patients with limited mouth opening.
• vii. Presence of intraoral pathological lesions.
• viii. Diabetic (HbA1c >7.5%)

The author of "study will publish it in an internationally acknowledged journal.

The study is based on different technical procedures of fabrication of the frameworks. Since these differences are visible, the operator, the assessor and the technician involved in the study cannot be blinded. Since blinding was not possible, randomization was delayed till the prosthetic phase to avoid any performance bias in the surgical steps. But the statistician will be blinded .