Stresses in Premolars Restored Using Different Post-and-Core and Crown Materials: A Finite Element Analysis Study

To investigate the influence of three post-and-core systems and two crown materials on stresses in restored premolars using finite element analysis (FEA).

A maxillary second premolar 3D model was created in SolidWorks 2014 (Dassault Systémés). Severe loss of tooth structure was simulated with six restorative options: (1) glass-fiber-reinforced composite post and composite core (GFRC) + CAD/CAM leucite-reinforced glass-ceramic crown (LRC); (2) carbon-fiberreinforced composite post and composite core (CFRC) + LRC; (3) metal cast post-and-core (MPC) + LRC; (4) GFRC + CAD/CAM composite resin crown (CC); (5) CFRC + CC; and (6) MPC + CC. Three-point occlusal loading (150 N) was simulated and von Mises and maximum principal stresses were calculated.

Although maximum von Mises stresses in the crown and dentin were similar across groups (137.9 to 139.2 MPa crown; 17.2 to 19.6 dentin), there were important differences in stress distribution in dentin. Maximum stresses were on the bottom of the post preparation cavity only in the MPC + CC group. Stress values for the posts were CFRC (4.8 MPa) > GFRC (6.7 MPa) > MPC (10.3 MPa). CC-restored models presented higher von Mises stresses for the post-and-core compared to the LRC groups. Maximum principal stresses were lower compared to von Mises stresses, following the same trend, and were distributed similarly in all groups.

Both GFRC and CFRC showed favorable stress distribution in the dentin and restorative materials, while MPC increased stresses in the core, post, and post cement. The more rigid crown material seems to transmit less stress to the underlying core and crown cement compared to CC.