Influence of occlusal loading on stress patterns at the bone-implant interface by angulated abutments in the anterior maxilla: A three-dimensional finite-element study

Abstract

Background: The long-term success of implant supported prosthesis depends on many variables. In addition to the osseointegration rules, a clinician should consider also the biomechanical factors like angulation of the abutment that may have a profound influence on the stress levels on bone for long-term function of implant-supported prosthesis. Purpose : A 3D finite element method was used to evaluate the von Mises stresses (ΣEmax ) generated in varying thickness of cortical bone under axial and combined loading conditions by four angulated abutments in the anterior esthetic zone. Materials and Methods: The model resembles the maxillary bone, and the material properties similar to the bone are introduced in the model and clinical loading conditions were simulated. Von mises stresses occurring for four angulated abutments (0, 15, 20, 25 degree) in (a) compact and cancellous bone, (b) thick and thin compact bone, (c) subjected to axial and combined loading, were calculated. Results: ( a) Von Mises stresses (∑E max ) were higher in the cortical bone compared to the cancellous bone and were concentrated in the crestal (facial) region in both types of bone. (b) The ∑E max values of 0, 15 degree abutments in thin bone and 0, 15, 20 degree abutments in thick bone were within the physiological remodeling zone. (c) Stress values for a 25 degree abutment in both types of bone were above the resorption limit. (d) Stress values were higher due to combined loading compared to axial loading irrespective of the angulation or quality of bone present. (e) Clinically, within a load of 178 N angulated abutments up to 20 degrees can be placed in the anterior maxillary zone.