Strength of monolithic ceramic crowns supported by incisors

Abstract

Monolithic restorations are becoming increasingly popular due to the reduction of technical complications. The upper incisors are the most affected teeth due to their location and protrusion.Aim. To determine the strength on models of incisors restored with monolithic crowns made of aluminum oxide and lithium disilicate.Materials and methods. The finite element method created 2 models for the upper incisor. In the mesh model with an aluminum oxide monocrown, the number of nodes was 130185, the number of elements was 90934. In a mesh model with a lithium dioxide monocrown, the number of nodes was 130,000, the number of elements was 96,000. 3D models were built and analyzed in the ANSYS environment.Results. In the alumina model, when loaded in the medial side (X), the horizontal and vertical forces were 0, in the vestibular side, the vertical force was -190 N, and the horizontal was 0, in the direction of the main axis of the tooth, the horizontal force was 15. In the lithium disilicate model, the maximum stresses mvM in dentin were 13.7 MPa, in cement – 18.5 MPa, in the crown – 61.8 MPa. Tensile, shear, and compression contact stresses at the adhesive interface between cement and dentin around the lithium crown and post were 11.9 MPa, 3.5 MPa, and 17.2 MPa, respectively.Conclusions. A finite element analysis of an incisive endocrown based on aluminum oxide and lithium disilicate was successfully performed. Based on these results, an endocrown can be considered as an aesthetic and clinically feasible restorative approach for endodontic treatment of central incisors.