Influence of prefabricated post screw head design on the stress pattern in the core and crown. Finite element stress analysis study

Abstract

Objectives: This study evaluated the influence of dental post head design on the stress distribution in the core and crown structure as an in vitro study.
 Materials and Methods: 3D finite element model prepared for three different stainless steel post head designs (rectangular with sharp line angle (A), rectangular with fillet line angle (B), and post with round head (C), inserted in single rooted tooth and retained the composite core and zircon crown. Two configurations of load (100) Newten were applied vertically (V) and lateral oblique (LO) on the occlusal surface of the crown. The results were analyzed and the maximum Von Mises stress option of the stress analysis, at the core and crown parts were compared.
 Results: The results shown that the Maximum Von Mises stresses value in design A (45.58, 186.16) MPa, design B (44.48, 183.71) MPa and design C (29.31, 12984) under V load and LO load in sequence. The maximum Von Mises stress location was at the cervical margin of the crown, in design A and B, while located at the top surface of the core for design C under both load configurations. The stresses were concentrated at the top surface of the core in designs A and B, whereas, the stress pattern distributed uniformly in the core structure for design C.
 Conclusions: The round post screw head design produces more benign stress distribution under different occlusal load compared with rectangular shape particularly at the crown margin.