# Viscoelastic Modeling Aided Experimental Optimization toward Fracture-Resistant Porcelain-Veneered Zirconia and Lithium Disilicate Restorations

> **NIH NIH R01** · UNIVERSITY OF PENNSYLVANIA · 2020 · $457,125

## Abstract

Project Summary/Abstract
Dental crowns and bridges are usually constructed by applying an esthetic porcelain veneer to a strong core.
Ceramic core materials, such as zirconia and lithium disilicate, are currently favored for their ease of fabrication
and for their strength. While porcelain chipping and fractures are observed in all types of veneered dental
prostheses, they are particularly prevalent in porcelain-veneered zirconia. The high chipping/fracture rate is
due predominantly to residual stresses introduced by the high-temperature veneering process. However,
comprehensive knowledge of key material, design, and processing parameters that govern residual stresses
remains obscure. The long-term goal of this project is to improve the fracture resistance of porcelain-veneered
prostheses through the reduction of deleterious residual tensile stresses, in conjunction with superior design of
a graded veneer/core interface. Accordingly, the overall objectives in this application are to develop a rigorous
viscoelastic graded finite element method to guide the design of next-generation fracture-resistant porcelain-
veneered ceramic prostheses, and to use clinically relevant fracture mechanics test methods to validate finite
element model predictions. The central hypothesis is that the incidence of chipping and fracture of porcelain-
veneered ceramics can be reduced to the levels seen in porcelain-fused-to-metal prostheses, through the
optimization of material, design, and processing parameters. This hypothesis is formulated on the basis of
preliminary results produced in the applicants' laboratories. To test this hypothesis, we will pursue two specific
aims: (1) Develop a rigorous viscoelastic graded finite element model, and use this model to optimize the
residual stress profile in anatomically-correct porcelain-veneered prostheses through the tailoring of material,
design, and processing parameters. Validate model predictions against direct measurement using the Vickers
microindentation method; (2) Experimentally quantify resistance to veneer chipping and fracture of porcelain-
veneered prostheses with optimal material, design, and processing parameters relative to their bilayer
counterparts and a commercial porcelain-fused-to-metal restoration, using edge-chipping methodology and
mouth-motion fatigue testing. The approach is innovative because it departs from the status quo by developing
a novel viscoelastic graded finite element method and utilizing this model to design continuously graded
veneer/core interfaces. The proposed research is significant because it vertically advances the understanding
of how stress profiles in all-ceramic prostheses can be tailored for better fracture resistance. Ultimately, such
knowledge will bring us closer to a solution of a pervasive clinical problem—chipping, delamination and
fracture of porcelain veneered prostheses—leading to reduced morbidity of dental prostheses and cost of
replacement to the public.

## Key facts

- **NIH application ID:** 10273914
- **Project number:** 7R01DE026279-05
- **Recipient organization:** UNIVERSITY OF PENNSYLVANIA
- **Principal Investigator:** JEONGHO KIM
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $457,125
- **Award type:** 7
- **Project period:** 2020-09-30 → 2022-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10273914

## Citation

> US National Institutes of Health, RePORTER application 10273914, Viscoelastic Modeling Aided Experimental Optimization toward Fracture-Resistant Porcelain-Veneered Zirconia and Lithium Disilicate Restorations (7R01DE026279-05). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10273914. Licensed CC0.

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