Biomechanical behavior of teeth without remaining coronal structure restored with different post designs and materials.

The aim of this study was to access the biomechanical behavior of teeth without remaining coronal structure when restored with posts of different materials and configurations. Fifty bovine teeth (n=10 per group) with standard dimensions were restored as follows: cast post and core (CPC), prefabricated metallic post (PFM), parallel glass-fiber post (P-FP), conical glass-fiber post (C-FP) or composite core (no post, CC). The survival rate during thermomechanical challenging (TC), the fracture strength (FS), and failure pattern (FP) were evaluated. Finite element models were realized to evaluate the stress distribution with a 100N load. All post-containing teeth survived TC, while CC had 30% of failures. CPC and C-FP had the higher fracture strength, but a high number of irreparable fractures (60%), such as PFM (70%). Von Mises analysis has shown the maximum stresses into the canal in groups restored with metallic posts, while glass-fiber posts and CC presented the maximum stresses at load contact point in the crown. CPC led to higher modified von Mises (mvM) stress in the cervical third of dentin. However, mvM values did not reach the dentin fracture limit for any group. Analysis of maximal contact pressure has shown better stress distribution along with the dentin interface in post-containing groups, especially for CPC.