A particle swarm-based algorithm for optimization of multi-layered and graded dental ceramics

Abstract

The thermal residual stresses (TRSs) generated owing to the cooling down from the processing temperature in layered ceramic systems can lead to crack formation as well as influence the bending stress distribution and the strength of the structure. The purpose of this study is to minimize the thermal residual and bending stresses in dental ceramics to enhance their strength as well as to prevent the structure failure. Analytical parametric models are developed to evaluate thermal residual stresses in zirconia-porcelain multi-layered and graded discs and to simulate the piston-on-ring test. To identify optimal designs of zirconia-based dental restorations, a particle swarm optimizer is also developed. The thickness of each interlayer and compositional distribution are referred to as design variables. The effect of layers number constituting the interlayer between two based materials on the performance of graded prosthetic systems is also investigated. The developed methodology is validated against results available in literature and a finite element model constructed in the present study. Three different cases are considered to determine the optimal design of graded prosthesis based on minimizing (a) TRSs; (b) bending stresses; and (c) both TRS and bending stresses. It is demonstrated that each layer thickness and composition profile have important contributions into the resulting stress field and magnitude.

Color Aspect of Monolithic Zirconia Restorations: A Review of the Literature

“…Multi‐layered zirconia ceramics have been introduced as a solution for the color enhancement of monolithic zirconia restorations . These ceramics have originated from the concept of creation of zirconia blanks containing different layers with various translucencies and shades.…”

Clinical factors affecting the translucency of monolithic Y-TZP ceramics

“…Recently, highly translucent multi-layered monolithic zirconia ceramics have been proposed as a solution for the colour improvement of monolithic zirconia restorations [28,54,55]. They have derived from the concept of production of zirconia blocks containing different layers with various translucencies and shades.…”

On the Effect of Friction on Tibiofemoral Joint Kinematics

“…As future research directions, the proposed model can be extended to account for the dynamics of the patella-femoral joint in addition to the tibiofemoral joint as well as to take fluid lubrication into account while handling fluid-structure interaction [105][106][107]. Moreover, the suggested approach can be utilized to optimize the design and material properties of TKAs to improve their lifetime and tribology performance, using optimization approaches such as genetic algorithm (GA) and particle swarm optimization (PSO) algorithms [108]. The friction models considered in this article are not able to capture dynamic characteristics of the friction phenomenon, e.g., pre-sliding and frictional lag.…”