Patients need Endocrowns for their teeth usually use Emax as an etchable ceramic. Yet they have disadvantages that may influence the outcome of the endocrowns, among which is the high stiffness and rigidity owing to the higher modulus of elasticity (67.2 GPa)( compared to natural dentin (18.6 GPa) which may affect the marginal adaptation.so a less rigid material is needed. PEEKs (polyetheretherketones) are presented as alternative materials to metal and glass ceramics, Their elastic modulus comparable to those of cortical bone and dentin so the polymer could exhibit good stress distribution. Also they have high fracture resistance, and low abrasion to the antagonist enamel.

.but the investigators have to know clinically it is performance , so the investigators are going to have Parallel groups in a randomized clinical trial.

Inclusion Criteria:

All subjects are required to be:

• From 18-60 years old, and able to read and sign the informed consent document.
• Physically and psychologically able to tolerate conventional restorative procedures
• Have no active periodontal or pulpal diseases.
• Willing to return for follow-up examinations and evaluation

Exclusion Criteria:

• Patients in the growth stage with partially erupted teeth
• Patient with fractured teeth of more than 50% enamel loss
• Patients with poor oral hygiene and motivation
• Pregnant women
• Psychiatric problems or unrealistic expectations
• Lack of opposite occluding dentition in the area intended for restoration