新型鈦合金的發展：其對牙科植體機械強度影響之文獻綜述

由於鈦具有優異的生物相容性，因此在牙科植體中被廣泛使用，且相關研究已非常深入。然而，有關機械性問題，特別是彈性模數的研究相對較少。商用鈦植體如 CP-Ti 或 Ti-6Al-4V 的彈性模數較高（超過 100 GPa），與人體骨骼的彈性模數（10–30 GPa）不匹配，導致「應力屏蔽效應」。為了解決此問題，研究者嘗試添加鋯、鈮、和鉬等不同金屬至鈦合金中，以降低其彈性模數。此外，聚醚醚酮因其低彈性模數而成為鈦合金的潛在替代材料和重要的比較參考。本研究旨在比較新型鈦合金的機械性質，並總結其優越機械性能的關鍵因素，以尋找具有潛力取代現有商用牙科植體的候選材料。相關文獻篩選自過去十年內發表於 PubMed、ScienceDirect 和 Google Scholar 的英文文章。納入標準為關於鈦合金、β型鈦合金、低彈性模數、機械性質的研究；排除標準則包括生物相容性研究、電化學性質、植體基台、表面塗層、多孔植體，以及非鈦合金。研究結果顯示，Zr-25Ti-7.5Mo 和 Ti-10Nb 的彈性模數分別為 24.4 GPa 和 35.42 GPa，符合理想範圍，並具備良好的機械性質，使其成為開發次世代牙科植體的極具潛力的候選材料。增加鈦合金中 β 相的含量是降低彈性模數的關鍵因素。快速冷卻熱處理、選擇性雷射燒熔等積層製造技術，以及優化孔隙率被認為是有效實現此目標的方法。此外，聚醚醚酮被確認為另一種潛在替代材料，但儘管碳纖維強化可提升其性能，其相較金屬植體較低的強度仍是一項重要限制。

Titanium is frequently used in dental implants due to its excellent biocompatibility, which has been extensively studied. However, mechanical complication, particularly the issue of elastic modulus, remain less explored. Commercial titanium implants like CP-Ti or Ti-6Al-4V exhibit significantly high elastic modulus (over 100 GPa), which mismatch human bone (10-30 GPa), causing the “stress shield effect”. To address this issue, researchers have investigated the addition of various metals, such as zirconium (Zr), niobium (Nb), and molybdenum (Mo), into titanium to reduce the elastic modulus. Polyetheretherketone (PEEK) has also emerged as a potential alternative due to its low elastic modulus, making it a valuable comparative reference for titanium alloys. The purpose of this study is to compare the mechanical properties of newly developed titanium alloys and summarize the factors contributing to their superior mechanical properties, aiming to identify potential candidates for replacing currently commercialized dental implants. Relevant articles published in English within the past 10 years were selected from Pubmed, ScienceDirect, Google Scholar. Inclusion criteria included studies focusing on titanium alloy, β type titanium alloy, low elastic modulus, mechanical properties. The exclusion criteria encompassed biocompatability, electrochemical properties, implant abutment, surface coating, porous implant, and non-titanium alloys. The results showed that Zr-25Ti-7.5Mo and Ti-10Nb exhibits elastic modulus within desirable range (24.4 GPa and 35.42 GPa, respectively), while maintaining excellent mechanical properties, making them highly promising candidates for the development of next-generation dental implants. Increasing the the β phase content in titanium alloys is a key factor for reducing their elastic modulus. Methods such as rapid cooling heat treatment, additive manufacturing techniques like selective laser melting (SLM), and optimizing porosity have been identified as effective approaches to achieve this goal. PEEK was identified as another potential alternative, but its relatively lower strength compared to metallic implants remains a significant limitation despite carbon fiber reinforcement.