Marginal Evaluation of Zirconia Reinforced Lithium Disilicate Partial Coverage Restoration of Egyptian Posterior Teeth.

Evaluation of Marginal Adaptation of Onlay Restorations Constructed From Two Types of Glass Ceramics: A Randomized Clinical Trial

Objective: To evaluate the marginal adaptation of the zirconia reinforced lithium disilicate (VITA AMBRIA) glass ceramic Inlay/Onlay compared with lithium disilicate(IPS emax Press) glass ceramic Inlay/Onlay in decayed posterior teeth.

A randomized controlled clinical trial, a double-blind (patient and examiner) is conducted by one trained and calibrated operators who perform all restorative procedures. The restorations will be evaluated by a blind and calibrated two examiner using the FDI (World Dental Federation) criteria. A total of 25 subject will be randomly assigned to each group for a total of 50 subject. The randomization sequence will be generated (www.randomlists.com/team-generator) and to ensure the confidentiality of the allocation, this will be used opaque, sealed and numbered envelopes in series. These will be kept with an independent researcher for the moment of inclusion of the subjects.

Both groups will receive Inlay/Onlay preparation . Digital impression will be taken, wax pattern for the Inlay/Onlay restoration will be designed and milled using CAD/CAM(computer-aided design/computer-aided manufacturing) software. After that, the wax pattern will be invested and final Inlay/Onlay restoration will be constructed from VITA AMBRIA and IPS e.max press ingots according to manufacturing instructions.

Inclusion Criteria:

• The patient is healthy.
• 18-50 years old.
• Normal occlusion.
• Good oral hygiene.
• Tooth with complete root apex.
• Tooth with moderate coronal decay.

Exclusion Criteria:

• Patient Incapable of self-care, mental illness, undergoing radiotherapy, diabetic patient, allergy to one of the materials used, pregnancy, smoker, parafunctional habits, poor oral hygiene, severe periodontitis, tooth need vital pulp therapy or surgical crown lengthening or marginal elevation, tooth with enamel or dentin hypoplasia or hypocalcification, Mallaligned or malformed teeth and adjacent or opposing teeth are missed.