The Finite Element Analysis of the Impact of Ferrule Height and Post-Core Materials on Stress Distribution in Incisors.

Abstract

<h4>Objective</h4>Ferrule heights and post-core materials are key factors for post-core restorations, and the interaction between them needs further investigation. This study used finite element analysis to evaluate the stress distribution of post-core models with different materials and varying ferrule heights.<h4>Methods</h4>A 3-dimensional finite element model of the maxillary central incisor was constructed, along with 3 additional groups with different ferrule heights: 2 mm, 1 mm, and 0 mm. Meanwhile, various materials were designed to form the post-core: Zirconia, Titanium, Fiberglass, PEEK, and CFR-PEEK (PEEK reinforced by 30% carbon fiber). A 100 N load was applied at an angle of 45° with the tooth's longitudinal axis on the palatal surface of the crown. The peak von Misses (VM) stress values were recorded.<h4>Results</h4>As the ferrule height increased, a stress reduction was observed at post-core and post-cement interfaces, while the stress in root and cement interfaces increased; meanwhile, the peak VM stress of the post-core decreased among all groups, while that of rigid material groups (Zirconia/Titanium) decreased more significantly; in addition, the peak VM stress at post-core and cement interfaces increased, and that of the 0 mm ferrule PEEK group was the highest.<h4>Conclusion</h4>Ferrule heights and post-core materials affect stress distribution on post-core restorations. A sufficiently large ferrule height can effectively compensate for the stress concentration of highly rigid materials, and PEEK post-core should be carefully used in 0 mm ferrule cases.<h4>Clinical relevance</h4>This study would provide suggestions for dentists to choose appropriate post-core materials according to various ferrule heights.