Lower Elastic Modulus of Novel Zr58Cu25Al14Nb3 Dental Implants Improves Stress Distribution and Osteogenesis in Peri-implant Alveolar Bone Under Physiological Loading

While implant materials with bone-mimetic elastic moduli are theoretically advantageous for reducing the stress shielding effect, the underlying mechanism remains incompletely understood, particularly in alveolar bone applications. In this study, we investigate the mechanism of excellent peri-implant bone quality of a Zr58Cu25Al14Nb3 bulk metallic glass (Nb3) dental implant in terms of its lower elastic modulus than commercial pure titanium (cpTi) and the stress distribution under masticatory mechanical loading. In vitro, Nb3 exhibits enhanced osteogenic potential over cpTi. In vivo, rat maxillary molar implants are subjected to a controllable cyclic loading program (10 N, 3 Hz, 0.12 s duration, 1800 cycles/day). The animal model coupled finite element analysis confirms that the lower elastic modulus of Nb3 implants promotes the more physiological stress distribution, and thus reduces stress concentration while increasing strain energy density in peri-implant bone. Histomorphometry reveals that loaded Nb3 implants significantly accelerate mineral apposition rate, upregulate collagen III, and increase osteoblast density while reducing osteocyte number, demonstrating improved mechano-adaptation. Transcriptomics identify coordinated upregulation of osteogenic, angiogenic, and mechanosensitive markers in Nb3-loaded bone. Immunohistochemistry validates elevated expression of osteopontin and periostin, key mediators of mechanical signaling. These findings establish that Nb3’s optimal elastic modulus enhances peri-implant bone quality through biomechanical optimization of stress transfer that further activates mechanotransductive osteogenesis, providing a material-based solution to stress shielding.尽管具备骨匹配弹性模量（bone-mimetic elastic moduli）的种植材料在理论上可有效降低应力遮挡效应（stress shielding effect），但其背后的作用机制仍未完全阐明，在牙槽骨（alveolar bone）应用场景中这一问题尤为突出。本研究以Zr₅₈Cu₂₅Al₁₄Nb₃块状金属玻璃（bulk metallic glass，Nb₃）牙科种植体为研究对象，围绕其相较于商业纯钛（commercial pure titanium，cpTi）更低的弹性模量，以及咀嚼机械载荷下的应力分布特征，探究该种植体获得优异种植体周围骨质量的内在机制。体外实验（in vitro）结果显示，Nb₃的成骨潜能优于cpTi。体内实验（in vivo）中，研究团队对大鼠上颌磨牙种植体施加可控循环加载方案：载荷为10 N、频率3 Hz、单次加载时长0.12 s、每日1800个循环。结合动物模型与有限元分析（finite element analysis）的结果证实，Nb₃种植体更低的弹性模量可促进更符合生理状态的应力分布，进而在降低应力集中（stress concentration）的同时，提升种植体周围骨组织的应变能密度（strain energy density）。组织形态计量学（histomorphometry）分析表明，接受循环加载的Nb₃种植体可显著加快矿化沉积速率（mineral apposition rate），上调III型胶原（collagen III）的表达，增加成骨细胞（osteoblast）密度并减少骨细胞（osteocyte）数量，证实其机械适应性（mechano-adaptation）得到改善。转录组学（transcriptomics）分析发现，加载后的Nb₃种植体周围骨组织中，成骨、血管生成（angiogenic）以及机械敏感（mechanosensitive）相关标志物呈现协同上调趋势。免疫组织化学（immunohistochemistry）验证结果显示，机械信号转导的关键介质——骨桥蛋白（osteopontin）与骨膜蛋白（periostin）的表达水平显著升高。本研究结果表明，Nb₃种植体的最优弹性模量可通过优化应力传递的生物力学特性，进一步激活机械转导型成骨过程，从而提升种植体周围骨质量，为应力遮挡效应提供了一种基于材料学的解决方案。