1.Research progress of treated dentin matrix in vital pulp therapy
Journal of Prevention and Treatment for Stomatological Diseases 2025;33(4):320-327
There has been an increase in research interest and application of treated dentin matrix (TDM) in vital pulp therapy (VPT) in recent years. TDM has excellent biocompatibility and contains transforming growth factor-β, bone morphogenetic protein 2, and other odontogenesis/osteogenesis-related proteins and factors that promote odontogenic differentiation of dental stem cells. TDM-based products, ranging from powders and pastes to injectable composite gels and gel scaffolds, have gained increasing consensus for their ability to induce dentin-like tissue regeneration. Animal and clinical studies found that TDM has significant advantages over traditional pulp capping materials, as it can form well-organized layers of odontoblast-like cells and uniform dentinal tubule structures. Future challenges of TDM in VPT application are primarily focused on improving mechanical properties and addressing potential immune rejection issues with heterologous material use. Additionally, further studies should be conducted on the odontogenetic pathway mechanism of TDM and the immune regulatory capabilities of xenogeneic dentin matrix materials. Utilizing TDM to construct tissue engineering scaffolds for VPT presents a promising strategy. This article reviews the structure and biological properties of TDM and related materials, thoroughly examines their progresses in the field of VPT, and discusses their current challenges as well as future research directions.
2.Stress Analysis of Aortic Vessels under Stent Graft
Shuaixing YANG ; Ming ZHANG ; Xiangchen DAI ; Yuguo XUE ; Haofei LIU
Journal of Medical Biomechanics 2021;36(1):E014-E021
Objective To simulate the interaction between the stent graft (SG) and the aortic wall with finite element (FE) analysis by considering the influence of residual stress field, so as to study the stent influence on stress distributions of the aortic wall. Methods The three-dimensional (3D) residual stress field was generated in an idealized bi-layered thick-wall aortic model via a stress-driven anisotropic growth model by reducing the transmural stress gradient. Upon virtually deploying the SG, the stress on the aortic wall was calculated. Results The 3D residual stress field, corresponding to an opening angle of 117.5°, was shown to reduce the transmural stress gradient in both the circumferential and axial directions. The maximum stress was found at the contact area between aortic wall and wave peak of the stent. At 20% oversize ratio of the stent, the maximum stresses on the aortic wall in circumferential and axial direction were 412 and 132 kPa, respectively, while the in-plane shear stresses σrθ and σrz were both 78 kPa. Under residual stress, the maximum radial, circumferential and axial stresses were decreased by 14.9%, 40.5% and 33.8%, respectively, while the maximum shear stresses σrθ ,σrz,σθz were reduced by 2.5%, 7.1% and 27%, respectively. With the increase of oversize ratio from 10% to 20%, the maximum radial, circumferential and axial stresses were increased by 316%, 129% and 41%, respectively, while the maximum shear stresses σrθ ,σrz,σθz were increased by 661%, 450% and 466%, respectively. Conclusions The residual stress can effectively reduce the transmural stress gradient. Both the residual stress and the oversize ratio of the stent play an important role in modulating the wall stress distribution and the maximum stress.


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