PSI - Issue 79

Mays H. Udah et al. / Procedia Structural Integrity 79 (2026) 53–64

54

resulting in discomfort or pain [1-3]. Clinical research over the past several decades has extensively analyzed tooth fractures under various conditions, including fractures in repaired teeth and those treated with root canals [4-6]. Cracks compromise the structural integrity of teeth, making it essential to understand tooth failure mechanisms to minimize damage and inform repair and restoration strategies [7]. Timely crack detection is vital to preserving tooth structure. The dentin-enamel boundary plays a critical role in limiting crack propagation, due to its fracture toughness. The surfaces between enamel and dentin act as a fracture deterrent [7, 8]. As teeth age, they experience increased brittleness, leading to accelerated fracture risk [9]. Early crack detection is crucial for maintaining tooth health and preventing further damage [10-11]. Young dentin is more resistant to crack propagation compared to older dentin, highlighting the importance of addressing the effects of aging on tooth integrity [4]. The contribution of plasticity or bridging in dental enamel is often negligible, as fracture toughness primarily results from the bridging at the dentin-enamel junction (DEJ). Additionally, some studies have utilized the Linear Elastic Fracture Mechanics (LEFM) approach to investigate stress distribution in teeth, focusing on cracks in regions with high elasticity [7]. Modeling crack formation has become essential in various fields, driven by the need to estimate crack toughness and predict crack paths for design and repair decisions. Finite Element Analysis (FEA), a powerful numerical method, is commonly employed to assess the stresses and strains in complex mechanical systems, including human tissues [12]. This capability to simulate mechanical properties makes FEA widely used in the field of oral biomechanics [13 16]. Recent analyses have shown that the roots of teeth with lateral cavities are more prone to stress concentration, potentially leading to fractures under masticatory forces [17]. FE Modeling is also used to assess the durability of restorative materials under masticatory stresses, providing a cost-effective means of evaluating material performance [18-20]. In this context, the study utilizes the LEFM approach to model dental fractures, with a particular focus on the crack path and characteristics. The study proposes a novel approach, simulating vertical cracks through load distributions and cyclic loading, which deviates from traditional methodologies [8, 21]. The 3D-FE analysis by Benazzi et al. [21] highlighted that stress distribution shifts during the loading process. These displacements alter the mode and direction of loading in activities such as chewing and closing, which can significantly affect tooth integrity. This research investigates how the magnitude of the applied force influences crack progression in teeth. It explores the role of dentin properties in crack development and growth. Additionally, the study proposes a combined simulation approach, integrating solid stress distribution models with fracture analysis under peak stress conditions. Key findings, including SIF, and fatigue life (S-N) estimations, are presented and validated. 2. Materials and methods 2.1. Numerical model For the 3D-FE model, ANSYS Workbench 2024 R2 (Swanson Analysis Systems, Inc., Houston, PA, USA) was employed. A human molar was scanned using HELIOS scanning software (Fig. 1a), and a 2D cross-section of the tooth was created in SOLIDWORKS for import into ANSYS (Fig. 1b). The primary FE mesh was generated in ANSYS. Following this, simulation tools within ANSYS, along with a postprocessor, were utilized to define boundary conditions, perform stress analysis, and simulate crack initiation and propagation, as illustrated in Fig. 1c. FE programs have been widely used and validated through numerous case studies in recent years [7, 22]. Several iterations of the model were analyzed to optimize mesh density and component partitioning. Validation of the 2D model was conducted by comparing the results with findings from existing literature. As a result, the use of more complex and time-consuming 3D models was deemed unnecessary for the current analysis.