ABSTRACT
The present work, utilizing the finite volume-based phase field method (FV-based PFM), aims to investigate the initiation and propagation of cracks in the second molar of the left mandible under occlusal loading. By reconstructing cone beam computed tomography scans of the patient, the true morphology and internal mesostructure of the entire tooth are implemented into numerical simulations, including both 2D slice models and a realistic 3D model. Weibull functions are introduced to represent the tooth's heterogeneity, enabling the stochastic distribution characteristics of mechanical parameters. The results indicate that stronger heterogeneity leads to greater crack tortuosity, uneven damage distribution, and lower fracture stress. Additionally, different cusp angles (50° and 70°) and pre-existing fissure morphologies (i.e., U-shape, V-shape, IK-shape, I-shape, and IY-shape) also significantly affect the mechanical performance of the tooth. The study reveals that different cusp angles affect the location of crack initiation. Overall, this work demonstrates the utility of the FV-based PFM framework in capturing the complex fracture behavior of teeth, which can contribute to improved clinical treatment and prevention of tooth fractures. The insights gained from this study can inform the design of dental crown restorations and the optimization of cusp inclination and contact during clinical occlusal adjustments.
ABSTRACT
OBJECTIVE: To determine whether risk factors other than hyperglycemia lead to failed osseointegration in patients with type 2 diabetes mellitus (T2DM) during the healing period. MATERIALS AND METHODS: We compared the success rates between patients with and without T2DM during the healing period at our center. Bone marrow mesenchymal stem cells (BMSCs) were cultured from subjects. Proteomics was used to detect differentially expressed proteins (DEPs) among the DM failure (DM-F), DM success (DM-S), and control (Con) groups. The correlation between the expression levels of nine target DEPs and medium glucose concentrations was investigated. RESULTS: Higher failure rates were observed in the T2DM patients. Fifty-two DEPs were found between the DM-F and DM-S groups. Seventy-three DEPs were found between the DM-F and Con groups. Forty-three DEPs were found between the DM-S and Con groups. Five target DEPs were expressed at the same levels in the medium with different glucose concentrations. Gene ontology annotation and functional enrichment analysis suggest that the DEPs detected in the DM-F group may affect the biological function and regulatory potential of BMSCs. CONCLUSIONS: The DEPs detected in the DM-F group can be intervention targets for to prevent implant failure in T2DM patients. Risk factors besides hyperglycemia may affect osseointegration during healing period.
