in the last years, dentistry is going to the concept of conservatism to preserve the most amount of tooth structure, so the evolution of new ceramic materials with invasive designs like (inlay- shaped and proximal box shaped) inlay retained bridge, the investigators can restore single missing posterior teeth with less invasive techniques and less rate of restoration fracture.

It has been demonstrated that a great amount of tooth structure is lost during the prosthetic preparations of abutments for full-coverage FDPs with tooth substance removal of 63% of 73%, this aggressive loss of tooth structure usually accompanied with pain and postoperative sensitivity. In comparison With the inlay-retained bridge, there is less amount of tooth substance loss. this clinical study will provide benefits for practitioners and clinicians by guiding them to choose a more conservative treatment plan with the better marginal fit, clinical performance and satisfaction for the patients on the long term. rather than other benefits like less chair time, less risk for pulp injury, less time and cost

Inclusion Criteria:

• Absence of periapical or periodontal or diseases
• sound abutment teeth or with small caries or filling on occlusal or proximal surfaces
• Maintenance of good oral hygiene
• No tooth mobility or grade 1 can be accepted
• Sufficient occluso-gingival tooth height (5mm)
• Good alignment of abutment teeth
• mesiodistal edentulous space preferred not exceed 12mm

Exclusion Criteria:

• Patients under the age of 18 or being incapable of taking out a contract
• Patients with any medical condition that impaired correct oral hygiene
• Endodontic ally treated abutment teeth
• a conspicuous medical or psychological history
• bruxism, or known allergic reaction to the materials used
• limited vertical space for the required connector height of 4mm
• pregnant female patients