Evaluation of the marginal and internal adaptation using silicon replica technique, which will be measured by digital microscope and clinical Performance using modified USPHS scoring system of Endo-crowns fabricated from Nano-ceramic Hybrid and Lithium di-silicate ceramic materials.

Evaluation of the marginal and internal adaptation using silicon replica technique, which will be measured by digital microscope and clinical Performance using modified USPHS scoring system of Endo-crowns fabricated from Nano-ceramic Hybrid and Lithium di-silicate ceramic materials.

Primary outcome: Marginal gap of the two groups will be measured using Silicon replica technique, Each replica will be sectioned bucco-lingually and mesio-distally into four segments named (MB, DB, ML, DL) and each segment has five reference points assigned at different positions, An overall of twenty reference points will be measured in each replica sample using a digital microscope.

Secondary outcome:

• Internal gap of the two groups will be measured using Silicon replica technique, which will be measured by digital microscope.
• Clinical Performance of the two groups will be evaluated using modified USPHS scoring system. (Color match, Marginal discoloration, Surface texture and Gross fracture)

Inclusion Criteria:

• From 18-50 years old, be able to read and sign the informed consent document.
• Have no active periodontal or pulpal diseases, have teeth with good restorations.
• Psychologically and physically able to withstand conventional dental procedures.
• Patients planned for a single coverage restoration in the posterior area.
• Able to return for follow-up examinations and evaluation.
• Patients have root apex of molar without evident damage and no root fracture.
• Good oral hygiene habits.
• Have a complete root canal therapy molar necessitating an Endo-crown restoration.

Exclusion Criteria:

• Patient less than 18 or more than 50 years
• Patients with severe clenching or bruxism.
• Patient with active resistant periodontal diseases
• Patients with poor oral hygiene and uncooperative patients
• Pregnant women
• Patients in the growth stage with partially erupted teeth
• Psychiatric problems or unrealistic expectations
• Patients with inadequate or low quality endodontic treatment.