The Hot Tooth Paradox of Thermal Gradient‑Driven Implant Fracture

Abstract

Objective: This study aims to develop a comprehensive framework combining analytical closed form solutions with coupled thermomechanical finite element modeling to investigate transient thermal loads on the propagation of pre-existing micro-cracks in a mandibular molar restored with a titanium dental implant.

Methods: A three-dimensional (3D) model was reconstructed from micro-CT data. Before numerical simulation, a one-dimensional analytical solution for transient heat conduction and resulting thermal stress in a cylindrical bi-material composite was derived to predict the critical crack depth. Subsequently, the Extended Finite Element Method (XFEM) was employed for a fully coupled temperature displacement simulation mimicking thermal shock (ΔT = 50oC). The analytical model served as a verification tool for the numerical stress prediction at the interface.

Results: The analytical model predicted a critical tensile hoop stress of 5.7 MPa at the bone-implant interface, closely matching the numerical prediction of 4.5 MPa (error < 11%). The analytical stress intensity factor solution for an edge crack confirmed that cracks deeper than aK ≈ 0.08 mm are unstable under the thermal shock, a criterion validated by the XFEM propagation model. The XFEM simulation showed dynamic propagation of a 0.1 mm pre-existing crack along the implant axis.

Significance: The validated framework provides a mechanistic explanation for peri-implant bone fractures unrelated to masticatory overload. The analytical solution offers a rapid clinical screening tool for material selection based on CTE mismatch, while the computational model captures the complex propagation path, providing a comprehensive toolkit for predicting thermomechanical fatigue life.

Keywords: Dental Implant; Thermomechanical Fatigue; XFEM; Analytical Modeling; Fracture Mechanics; Peri-implant Bone

Citation

Yaghoub Abdollahzadeh Jamalabadi M. The Hot Tooth Paradox of Thermal Gradient-Driven Implant Fracture. WebLog J Dent App. wjdapp.2026. f1201. https://doi.org/10.5281/zenodo.20962693