The goal of this study is to evaluate the clinical success rate (measured by retention) of endo-crowns fabricated from two hybrid ceramic materials (HC Hard blocks ) versus (Cerasmart) at 6, 12, and 18 months.

Secondary Objectives are:

1. To compare the incidence of restoration failures between the two materials
2. To assess marginal adaptation and marginal discoloration over time
3. To evaluate wear of opposing enamel quantitatively
4. To compare surface texture, color match, and luster between materials
5. To determine patient satisfaction with both types of restorations It will be a randomized, controlled, double-blind clinical trial with 1:1 allocation ratio.

Inclusion Criteria:

1. Age ≥21 years

2. Good general health (ASA I or II)

3. Willing and able to provide informed consent

4. Committed to follow-up appointments for 18 months

5. Root canal treated molars requiring restoration

6. Adequate remaining tooth structure:

   • Minimum 2mm ferrule height
   • Sufficient wall thickness (≥1.5mm)
   • At least 2 remaining walls

7. Opposing natural dentition or fixed prosthesis

8. Adequate periodontal health:

   • Probing depth ≤4mm
   • No bleeding on probing

9. Good oral hygiene with plaque score ≤20%

10. Sufficient mouth opening for clinical procedures

11. Normal occlusion and acceptable interocclusal space

Exclusion Criteria:

1. Pregnant or lactating women
2. Severe bruxism or parafunctional habits
3. Active periodontal disease
4. Active caries or inadequate oral hygiene
5. Less than 2mm ferrule height after preparation
6. Apical pathology or inadequate root canal treatment
7. Tooth mobility grade II or III
8. Known allergy to materials used
9. Uncontrolled diabetes (HbA1c >7.0%)
10. Radiation therapy in head and neck region
11. Temporomandibular joint disorders
12. History of poor compliance with dental appointments
13. Heavy smokers (>10 cigarettes/day)
14. Chronic use of medications affecting salivary flow
15. Unable to understand study requirements
16. Evidence of pulpal or periapical pathology