Different types of post and core have been used for several years for restoring anterior endodontically treated teeth, but their preparations involve various risks such as: root perforation, root weakness and tooth fracture. The introduction of adhesive systems and conservative restorations, make it possible to reconstruct damaged anterior endodontically treated teeth with conservative restoration as endocrowns. The hypothesis of this trial is that E-max CAD endocrowns will show comparably equal clinical performance if compared to E-max CAD crowns retained with fiber reinforced composite post and core system when treating anterior endodontically treated teeth..

This trial will be conducted on patients from the out patient clinic in the fixed prosthodontics clinic, Faculty of Oral and Dental Medicine, Cairo University.

• Adherence session will take place in the presence of the patients in the initial visit. This include that the patients will be informed by Abou El-Enein Y about the study steps and maintenance of oral hygiene instructions. Participant will be asked by Abou El-Enein Y if they have any problem like pain.
• Motivation and enforcing the maintenance of oral hygiene measures by Abou El-Enein Y.

The visits will be designed as follow:

• st visit: (Y.A) will call participants before tooth preparation procedure for preoperative records, face to face adherence reminder session, clinical examination, radiograohic examination, pre-operative photographing, Impression taking for study cast analysis and waxing up. Each participant will be asked to sign consent form written in patient native language.

  2nd visit: Tooth preparation for either e-max crown retained with fiber reinforced composie post or e-max endocrown, secondary impression and temporarization.

  3rd visit: Try in of the restoration.

  4th visit: Participants will be called again for final cementation.

  5th visit: Follow up.

Sample size: 12 in each group to be able to reject the null hypothesis that the rates for case and controls are equal with probability (power) 0.8. This number is to be increased to 16 in each group to compensate for possible losses during follow up.

Recruitment: The patients fulfill inclusion criteria will be selected from dental clinics of the Fixed Prosthodontics Department - Cairo University (internal recruitment).

Screening of patients will carried out until target number is reached (consecutive sampling).

Methods: Assignment of interventions:

Sequence generation: Radi I (R.I) will allocate participants in two different groups with 1:1 allocation ratio by using computerized sequence generation (www.randomizer.org).

Implementation: IR will be responsible for provide allocation generation and save it in the envelopes in secured place until the date of performing procedure.

Plans to promote participant retention & complete follow up: Telephone numbers of each patients and address will be taken and included in study, then phone calls and messages will be sent to remind patients before each appointment.

Data management: Guindy J (G.J) will enter all data electronically. Patient files are to stored in numerical order in a secured place in locked cabinets. G.J and Z.A will have access to data . Categorical data will be described as numbers and percentages. Data will be explored for normality using Kolmogrov-Smirnov test and Shapiro-Wilk test. Comparisons between two groups for normally distributed numeric variables will be done using the Student's t-test while for non normally distributed numeric variables will be done by Mann-Whitney test. Comparisons between categorical variables will be performed using the chi square test. A p-value less than or equal to 0.05 will be considered statistically significant. All tests will be two tailed. Statistical Methods will be done using IBM SPSS advanced statistics (Statistical Package for Social Sciences), version 21 (SPSS Inc., Chicago, IL).

Data Monitoring: Z.A will be responsible of data monitoring if any lost or delete occurs, in that case: back up data will be taken from (G.J) to provide hard copy for the requested data for Z.A.

Harms: If 50% of the patients showed any unfavorable signs as sever pain, irreparable fracture or shade changes which might affect the results. Then the treatment will be considered as stopped guidelines which necessitate stopping the treatment and interim analysis will be performed.

Consent: Researcher will discuss the trial with all patients. Then patient can have an informed discussion with the researcher. Researcher will obtain written consent from patients willing to participate in the trial. All consent forms will write in Arabic language (Appendix 1.1).

Access to data: The supervisors (Z.A and G.J) will give access to the data sets. All data sets will be protected by password. To ensure confidentiality, Participant study information will become confidentially.

Ancillary and post-trial care: All patients will be followed up 2 years even after the trial ends to report success of the treatments.

Dissemination policy: Study results will be published as partial fulfillment the Requirements for PHD degree in fixed prosthodontics.Topics suggested for presentation or publication will be circulated to the authors.

Data collection: The following assessment surveys (clinical evaluations) will done for both groups: All patients will be recalled after 3, 6, 9, and 12 months. For each recall examination, evaluator will performed the direct clinical evaluation using modified USPHS criteria for margin integrity and gross fracture. In addition, questionnaires will be used to evaluate patients' satisfaction and potential postoperative discomfort

Inclusion Criteria:

1. Age range of the patients from 20-60 years old who can read and sign informed consent document. Illiterate patients will be excluded.
2. Patients willing to return for follow-up examinations and evaluation.
3. Medically free patients or with controlled systemic disease.
4. No active periodontal disease.
5. Patients with anterior endodontically treated tooth/teeth indicated for Endocrown restoration (e.g. teeth without missing any wall, 2-3mm of sound tooth structure above cement-enamel junction).

Exclusion Criteria:

1. Patients under 20 years old.
2. Patients with bad oral hygiene and motivation.
3. Patients with psychiatric problems or unrealistic expectation (patient have phobia from dental treatments or needle bricks).
4. Patients with missing teeth opposing to the area intended for restoration.
5. Patients with parafunctional habits (clencing /bruxism).

no masking