Fracture modelling of zirconia crowns in dental implant systems using XFEM, phase-field methods, and Weibull statistics.

OBJECTIVES

This study aimed to develop a continuum-scale computational workflow for assessing fracture behaviour of zirconia crowns in dental implant systems under ISO 14801 loading conditions.

METHODS

A three-dimensional finite element model of a Matrix multi-level implant system was developed. Global elastic analysis was first used to evaluate the maximum principal tensile stress distribution in the zirconia crown. The extended finite element method was then applied to assess damage initiation and crack-path development. A localized phase-field fracture sub-model was used to examine regularized damage evolution in the critical region. Weibull weakest-link analysis was applied to full-crown tensile stress fields to estimate fracture probability as a function of load.

RESULTS

The global stress analysis identified the crown-indenter contact region as the critical tensile stress concentration. The extended finite element simulation predicted damage initiation beneath the indenter, followed by crack development toward the crown-implant interface. The phase-field sub-model showed progressive damage localization in the same critical region. Weibull analysis predicted a rapid increase in fracture probability within the load range corresponding to reported experimental fracture forces for similar implant-supported zirconia crowns.

SIGNIFICANCE: The proposed workflow combines deterministic crack modelling with probabilistic fracture assessment and provides a mechanics-based approach for evaluating fracture risk in implant-supported zirconia crowns.