The clinical performance of two different materials in endodontically treated teeth produced with CAD/CAM system will be evaluated and compared. After obtaining a signed informed consert form from all the patients, all restorations will be placed by a single clinician. All endocrown restorations will be produced using the same CAD/CAM system. 52 restorations will be fabricated using Lava Ultimate (LU, 3M Espe, Seefeld, Germany) blocks and 38 restorations will be fabricated using Celtra Duo (CD, Dentsply Sirona, York, PA, USA) blocks. All restorative procedures will be conducted according to manufacturers' instructions. Restorations will be scored using modified United States Public Health Service (USPHS) criteria after baseline, 6,12,36, 48, 60 months. Descriptive statistics will be performed using Chi-square and Fisher exact test.

Inclusion Criteria:

• Good general health
• Patients older than 18
• Teeth must receive endodontic therapy before restoration
• The periodontal condition had to be stabilized before restoration
• No subject complained of discomfort in teeth
• Radiograph revealing alveolar bone resorption of less than a third and no shadow around the periapical tissues
• Participants who provided writen informed consent were recruited in collaboration

Exclusion Criteria:

• Any teeth with microcracks or fracture lines
• Affected teeth without completed root canal treatment
• The defect was less than ¼ of crown or more than ¾ of the crown and the margin of the residual crown was more than 1 mm below the gingival level
• Poor oral hygiene and periodontal status which persisted or worsened after periodontal therapy and education
• Bruxism or clenching patients
• Poor general health or pregnancy
• Patients who have read the informed consent form and refused to be included in the study