Analysis of the effect of design parameters and their interactions on the strength of dental restorations with endodontic posts, using finite element models and statistical analysis

Abstract

Many previous studies, both in vitro and with model simulations, have been conducted in an attempt to reach a full understanding of how the different design parameters of an endodontically-restored tooth affect its mechanical strength. However, differences in the experimental set-up or modelling conditions and the limited number of parameters studied in each case prevent us from obtaining clear conclusions about the real significance of each parameter. In this work, a new approach is proposed for this purpose based on the combination of a validated 3D parametric biomechanical model of the restored tooth and statistical analysis using full factorial analysis of variance. A twostep approach with two virtual tests (with, respectively, 128 and 81 finite element models) was used in the present work to study the effect of several design parameters on the strength of a restored incisor, using full factorial designs. Within the limitations of this study, and for cases where the parameters are within the ranges that were tested, the conclusions indicate that the material of the post is the most significant factor as far as its strength is concerned, the use of a low Young's modulus being preferable for this component. Once the post material has been chosen, the geometry of the post is of less importance than the Young's modulus selected for the core or, especially, for the crown.

Influence of inhomogeneous dental posts on stress distribution in tooth root and interfaces: Three-dimensional finite element analysis

“…FRC posts as flexible posts accumulated lower MNS at the dentin-adhesive interface than the metal posts. These results are consistent with those reported by González-Lluch et al 31 In this study, both the post cement and the crown cement were considered identical. On the basis of the obtained results, we conclude that in the absence of the ferrule, the likelihood of cohesive failure at the post cement may be more than at the crown cement in all models except the carbon fiber post; however, with the presence of the ferrule, the likelihood of cohesive failure at the crown cement may be more than at the post cement.…”

“…Therefore, the maximum tensile stress (MTS) at the dentin and cement was calculated for each model in accordance with the material characteristics. 20,23,[28][29][30][31] Furthermore, maximum normal stress (MNS) and maximum shear stress (MSS) at the dentin-adhesive interface were calculated to assess the risk of loss of adhesion.…”

Comparação da eficiência na distribuição de tensões de diferentes modelos de retentores intrarradiculares: uma análise de elementos finitos tridimensional

“…Desse modo, a determinação da distribuição das tensões necessita de informações suficientes das características dos tecidos orais e dos materiais restauradores. O objetivo de obter esse conhecimento é prever o desempenho de sistemas restauradores e prover instruções para seu correto uso (Caputo;Standlee, 1987 (Assif et al, 1989;Yaman et al, 1998;Asmussen et al, 2005;Eraslan et al, 2009;González-Lluch: Pérez-González, 2015;. Além disso, o MEF é validado com sucesso por testes laboratoriais e observações clínicas (Maceri et al, 2007).…”

“…Sendo assim, um número crescente de estudos que abordam restaurações indiretas suportadas por núcleos são baseadas em análises de elementos finitos ( Asmussen et al, 2005;Eraslan et al, 2009;González-Lluch;Pérez-González, 2015;. O MEF realiza análises de modelos tridimensionais dos sistemas dentais, e é validado com sucesso por testes laboratoriais e observações clínicas (Maceri et al, 2007).…”

“…A avaliação apresenta os resultados considerando os critérios de Von Mises e de tensões máximas principais (Eraslan et al, 2005;Pereira et al, 2006;Maceri et al, 2007;Santos et al 2010;González-Lluch;Pérez-González, 2015;. Uma forma conveniente de demonstrar as tensões é utilizar uma representação de cor da distribuição das tensões (Asmussen et al, 2005;Eraslan et al, 2009), onde os dados numéricos calculados são transformados em gráficos de cor para melhor visualizar o fenômeno mecânico nos modelos e compará-los.…”