Optimizing the design of bio-inspired functionally graded material (FGM) layer in all-ceramic dental restorations

Abstract

Due to elastic modulus mismatch between the different layers in all-ceramic dental restorations, high tensile stress concentrates at the interface between the ceramic core and cement. In natural tooth structure, stress concentration is reduced by the functionally graded structure of dentin-enamel junction (DEJ) which interconnects enamel and dentin. Inspired by DEJ, the aim of this study was to explore the optimum design of a bio-inspired functionally graded material (FGM) layer in all-ceramic dental restorations to achieve excellent stress reduction and distribution. Three-dimensional finite element model of a multi-layer structure was developed, which comprised bilayered ceramic, bio-inspired FGM layer, cement, and dentin. Finite element method and first-order optimization technique were used to realize the optimal bio-inspired FGM layer design. The bio-inspired FGM layer significantly reduced stress concentration at the interface between the crown and cement, and stresses were evenly distributed in FGM layer. With the optimal design, an elastic modulus distribution similar to that in DEJ occurred in the FGM layer.

Functionally graded ceramics for biomedical application: Concept, manufacturing, and properties

“…Therefore, inspired by the structure of the DEJ, many efforts today are focusing on the development of FGCs layers, to be placed between the ceramic core and the dental cement, with the aim to grade the stiffness from the exterior to the inner part. Finite element simulations show that the presence of a FGM layer can significantly reduce the interfacial stress (up to 30%) and increase the critical crack length with the result of improved durability of the ceramic prosthesis.…”

Tuning the mechanical properties of functionally graded nickel and aluminium alloy at the nanoscale

“…15 While there are various applications of FGMs in aerospace, defense, nuclear, automotive, and other industries, FGMs also play a vital role in the medical sector. 6 Taking a wake-up look at the humans bone enhancement method, more in-depth work is needed on FGMs concerning health care, such as bone implantation, dentistry, etc.6 Cui et al investigated the optimization of functionally graded material layer architecture in all dental ceramic restorations, 16 and reported that the stress concentration in the natural tooth structure could be reduced with the help of functionally graded dentin-enamel junction which interconnects enamel and dentin. 16 This concept can be applied in all-ceramic dental restorations, for excellent stress reduction and distribution.…”

“…6 Taking a wake-up look at the humans bone enhancement method, more in-depth work is needed on FGMs concerning health care, such as bone implantation, dentistry, etc.6 Cui et al investigated the optimization of functionally graded material layer architecture in all dental ceramic restorations, 16 and reported that the stress concentration in the natural tooth structure could be reduced with the help of functionally graded dentin-enamel junction which interconnects enamel and dentin. 16 This concept can be applied in all-ceramic dental restorations, for excellent stress reduction and distribution. 16 Additionally, several experimental and numerical approaches have been utilized to investigate the thermomechanical characteristics of FGMs at bulk and microlevel.…”

“…16 This concept can be applied in all-ceramic dental restorations, for excellent stress reduction and distribution. 16 Additionally, several experimental and numerical approaches have been utilized to investigate the thermomechanical characteristics of FGMs at bulk and microlevel. [16][17][18][19][20][21] For instance, investigation on the dynamic stability of spherical FGM shells, 22 functionally graded circular plates subjected to radial compressive stress, 23 vibrational characteristics of functionally graded bars, 24 shear deformation analysis of FGM plates, 25 crack growth process in FGMs with the aid of digital image correlation, 26 creep deformation process in FGMs, 27 investigation of microhardness on FGM polymer composites, 28 quasi-static fracture analysis of FGMs, 29 elastoplastic 30 and deformation 31 analysis of functionally graded rotating disc, thermal stress, 32 unsteady heat conduction, 33 thermo-mechanical 34 analysis of 2D FMG plates and so on.…”

Additively Manufactured Dental Crown with Color Gradient and Graded Structure: A Technique Report

“…Material jetting or polyjet printing is an AM technique 10 and is capable of manufacturing different materials with different colors and properties with minimum postprocessing procedures 11–13 . Creating a bio‐inspired dental restoration that reproduces the structure and properties of human enamel and dentin has been a long‐term goal for clinical scientists 14–19 . Human tooth structure is graded with enamel being considered as an outer hard shell and dentin as a soft core 14,20,21 .…”