Influence of Inhomogeneous Crowns on Stress Distribution in Tooth Root and Cervical Margin by Finite Element Analysis

In the post and core crown restorations, the significant mismatch in the mechanical properties of the crown and dentin leads to stress concentration at dentin and cervical margin. A class of inhomogeneous materials (Functionally Graded Materials) has been proposed for dental crown to reduce the stresses at dentin and cervical margin. The aim of the present study was to investigate the effect of inhomogeneous crowns on stress distribution in tooth root and cervical margin by finite element analysis.
For the purpose of the study, a computer model of mandibular first premolar and its surrounding tissues, including periodontal ligament as well as cortical and trabecular bones were modeled. Homogeneous and inhomogeneous crowns were investigated by finite element analysis and the stress distribution results were compared.
Alumina crown resulted in the highest stress at the remaining dentin and cervical margin while inhomogeneous crown graded by index P=10 (FGM10) caused the lowest stress.
Finite element analysis showed that, inhomogeneous crowns are preferred than homogeneous crowns. Inhomogeneous crowns tailored in an adequate order may reduce the stress concentration at dentin and cervical margins and consequently reduce the possibility of root/restoration fracture.