Dental Crown Fracture Failure Risk Based on Strain Energy Density

Abstract

Purpose: This paper presents an analytical framework for predicting fracture risk in bilayer dental ceramic restorations—specifically porcelain-veneered zirconia (PVZ) crowns—based on the Averaged Strain Energy Density (ASED) criterion and a Fourier-series moisture diffusion model through quantitative non-dimensional analysis.

Scope: This is a theoretical and methods contribution. No original fracture tests are performed. Results are compared against published dental FEM studies and clinical survival data to validate trends. All threshold values are presented as analytical predictions requiring experimental confirmation in future work.

Methods: Material constants for zirconia, feldspathic porcelain, dentin, and enamel are assembled from recent literature. A quantitative non-dimensional similarity analysis is performed to establish the conditions under which the dental and other applications bilayers are mechanically equivalent. Full uncertainty propagation (±20% on all key parameters) is reported. The fatigue framework uses a Paris subcritical crack-growth model calibrated to ceramics. The diffusion model is assessed for both step-function and realistic oscillatory oral humidity inputs, and a viscoelastic correction for dentin relaxation is applied. A GPR surrogate is trained on independent simulated FEM data.

Key findings: (1) The zirconia–porcelain system has β = 3.23 vs. β < 1 for all systems, causing monotone interface-concentrated fracture risk. (2) The analytical critical RH threshold at the dentin–porcelain interface is ΔRH_c = 28%, compared to 39% for other applications gesso—a testable experimental prediction. (3) At the 5-year horizon under Paris fatigue, the unsafe fraction rises from ~55% (static) to ~75% for a 1.5 mm veneer. (4) Uncertainty propagation across ±20% parameter variation shifts the unsafe fraction by at most ±12 percentage points.

Limitations: The framework assumes perfect interfacial bonding, isotropic dentin, penny-shaped defect geometry, and linear hygroscopic expansion. Clinical recommendations derived herein require in vitro and in vivo validation before adoption.

Keywords: Dental Ceramics; Zirconia; Porcelain Veneer; Strain Energy Density; Penny-Shaped Crack; Bilayer Fracture; Moisture Diffusion; Hygroscopic Stress; Separation Line; Uncertainty Quantification; Paris Fatigue Law

Citation

Abdollahzadeh Jamalabad MY. Dental Crown Fracture Failure Risk Based on Strain Energy Density. WebLog J Dent Oral Disord. wjdod.2026.g1501. https://doi.org/10.5281/zenodo.21735938