Experimental study on the behavior at mechanical stresses of a prosthetic restoration made by full ceramics

Objectives. We have analyzed by finite element method the biomechanical behavior of an integral ceramic restoration to discover areas at risk of fracture. Material and method. The study was conducted with the ANSYS® software on a three-elements restoration, on which were applied experimental forces with different values on the 3 axes. Results. The values of total deformation, absolute deformation in the three directions and the relative deformation had low variations. The normal elastic strain to the X, Y and Z directions were small, mostly elongation. Some compressions also occur in the areas of application of the experimental forces. The entire structure is subjected to tensile stresses of the von Mises traction, except for the contact area between the central element and the distal post, where compression occurs. The highest values of shear stresses in the X direction are found on the active area in the mastication. In the mass of the crown there are negative shear stresses in the XY plane; on the active mastication surface the shear stresses become positive, with local maxima on the premolar 1. Discussions. All-ceramic restorations are currently being used more and more due to their special qualities, such as gingival tolerance and aesthetics. Experimental testing prior to clinical use is particularly important in estimating the long-term success of restoration. Conclusions. The prosthetic restoration studied has resistance to the applied experimental forces. More sensitive areas, which are susceptible to cracks in the ceramic mass in the case of occlusal overloads, are the distal fossa of the second premolar, the neck region of the second premolar and the contact area between the second premolar and the molar 1.