Clinical Performance Of Lithium Disilicate Crowns Restoring Endodontically Treated Teeth With Two Occlusal Preparation Schemes

Statement of the problem:

The endodontically treated teeth need to be restored back to form, function and aesthetics. The quality of the coronal restoration will directly impact on their survival and success. The aim of the coronal restoration of endodontically treated teeth is to provide the necessary strength for the restoration/tooth complex through tooth preparation in order to withstand functional stress and prevent crown and/or root fracture. The use of ceramic crowns has increased substantially in recent years because of their superior esthetics and high mechanical properties. Long term success of all ceramic crowns is affected by many factors and the failure patterns of these all ceramic crowns should be inspected closely to detect their clinical performance.

Rationale for carrying out the trial:

Endodontic treatment weakens posterior teeth and ought to be covered by crowns.The capability of these crowns to bear load relies on the preparation of an appropriate design and the selection of a crown material with adequate fracture strength and thickness. In vital teeth, the anatomic occlusal preparation design is followed such that the occlusal surface is reduced uniformly, maintaining the cusps and normal inclined planes but at a reduced height. This aids in minimizing the risk of pulp injury. In contrast, in non-vital teeth, this design can be modified such that the occlusal surface is prepared in two planes (buccal and lingual planes). A flat prepared occlusal surface provides less quantitative and better qualitative stresses when compared to an anatomically prepared surface