The finite element analysis of the effect of ferrule height on stress distribution at post-and-core-restored all-ceramic anterior crowns

Abstract

The purpose of this study was to compare the effect of ferrule with different heights on the stress distribution of dentin and the restoration-tooth complex, using the finite element stress analysis method. Three-dimensional finite element models simulating an endodontically treated maxillary central incisor restored with an all-ceramic crown were prepared. Three-dimensional models were varied in their ferrule height (NF: no ferrule, 1F: 1-mm ferrule, and 2F: 2-mm ferrule). A 300-N static occlusal load was applied to the palatal surface of the crown with a 135 degrees angle to the long axis of the tooth. In addition, two post and core materials with different elastic modulus were evaluated. The differences in stress transfer characteristics of the models were analyzed. Maximum stresses were concentrated on force application areas (32.6-32.8 MPa). The stress values observed with the use of a 2-mm ferrule (14.1/16.8 MPa) were lower than the no-ferrule design (14.9/17.1 MPa) for both the glass fiber-reinforced and zirconium oxide ceramic post systems, respectively. The stress values observed with zirconium oxide ceramic were higher than that of glass fiber-reinforced post system. The use of a ferrule in endodontically treated teeth restored with an all-ceramic post-and-core reduces the values of von Mises stresses on tooth-restoration complex. At rigid zirconium oxide ceramic post system, stress levels, both at dentin wall and within the post, were higher than that of fiber posts.

Finite element analysis of maxillary central incisors restored with various post-and-core applications

“…In other aspect, Asmussen et al 17) found that increasing the elastic modulus of the post caused decreased dentin stress. and this result was in agreement with an earlier in vitro investigation of the resistance of post-and-core restored teeth to cyclic loading 21) and with a theoretical study using FEM 24) . The result of this study was in agreement with authors who were mentioned above.…”

Zirconia ceramic post systems: a literature review and a case report

“…Of these papers, 62 were in vitro studies 12,14,29,32,33,35, , three were clinical studies 27,28,95) , and 14 were case reports and review articles with clinical application guidance 18,[24][25][26][96][97][98][99][100][101][102][103][104][105] . Of the 62 in vitro studies, 29 studies investigated the fracture strength 12,14,29,33,35, , 21 studies investigated the retentive strength of zirconia posts to both the tooth and cores of different materials , three studies investigated the microleakage of endodontically treated teeth restored with different post systems [88][89][90] , and four studies investigated the stress distribution in teeth restored with zirconia posts by using finite element analysis [84][85][86][87] . Other in vitro studies examined the yield strength 91) , radiodensitiy 92) , esthetic properties 32) , marginal gap formation 93) , stiffness and elastic limit 59) of zirconia posts, as well as the use of a proof-test technology to eliminate low-quality zirconia posts with critical microscopic defects so as to help reduce clinical failures 94) .…”

“…Four studies examined the stress distribution of teeth restored with zirconia posts by using finite element analysis [84][85][86][87] . On one hand, Eraslan et al 84) and Spazzin et al 87) reported that the stress values observed with zirconia posts were higher than with FRC posts, and they attributed this result to the high elastic modulus of zirconia.…”

“…On one hand, Eraslan et al 84) and Spazzin et al 87) reported that the stress values observed with zirconia posts were higher than with FRC posts, and they attributed this result to the high elastic modulus of zirconia. On the other hand, Toksavul et al 85) and Asmussen et al 86) suggested that zirconia posts created slightly less stress concentration in dentin than FRC and titanium posts.…”

Reliability of FEA on the Results of Mechanical Properties of Materials

“…The 3D model was generated using the Simpleware 4.1 software (Simpleware Ltd, Exeter, UK) and micro-CT images. All simulated structures (enamel, dentin, pulp and periodontal ligament) were included in the solid model and the 0.2-mm-thick periodontal ligament was designed by Boolean operations (12).…”