Bone grafts are typically categorized into four categories: autografts, allografts, xenografts, and synthetic alloplasts. While it was originally thought that all bone grafts should be slowly resorbed and replaced with native bone over time, accumulating evidence has in fact suggested that the use of nonresorbable xenografts is favored for certain clinical indications. Thus, many clinicians take advantage of the nonresorbable properties/features of xenografts for various clinical indications, such as contour augmentation, sinus grafting, and guided bone regeneration, which are often combined with allografts (e.g., human freeze-dried bone allografts [FDBAs] and human demineralized freeze-dried bone allografts [DFDBAs]). Thus, many clinicians have advocated different 50/50 or 70/30 ratios of allograft/xenograft combination approaches for various grafting procedures. Interestingly, many clinicians believe that one of the main reasons for the nonresorbability or low substitution rates of xenografts has to do with their foreign animal origin. Recent research has indicated that the sintering technique and heating conducted during their processing changes the dissolution rate of hydroxyapatite, leading to a state in which osteoclasts are no longer able to resorb (dissolve) the sintered bone. While many clinicians often combine nonresorbable xenografts with the bone-inducing properties of allografts for a variety of bone augmentation procedures, clinicians are forced to use two separate products owing to their origins (the FDA/CE does not allow the mixture of allografts with xenografts within the same dish/bottle). This has led to significant progress in understanding the dissolution rates of xenografts at various sintering temperature changes, which has since led to the breakthrough development of nonresorbable bone allografts sintered at similar temperatures to nonresorbable xenografts. The advantage of the nonresorbable bone allograft is that they can now be combined with standard allografts to create a single mixture combining the advantages of both allografts and xenografts while allowing the purchase and use of a single product. This review article presents the concept with evidence derived from a 52-week monkey study that demonstrated little to no resorption along with in vitro data supporting this novel technology as a “next-generation” biomaterial with optimized bone grafting material properties.

中文翻译：

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不可吸收同种异体骨移植的发展：生物学背景和临床观点


骨移植通常分为四类：自体移植、同种异体移植、异种移植和合成同种异体。虽然最初认为所有骨移植物都应随着时间的推移缓慢吸收并替换为天然骨，但越来越多的证据实际上表明，对于某些临床适应症，使用不可吸收的异种移植物是有利的。因此，许多临床医生利用异种移植物的不可吸收特性/特征来治疗各种临床适应症，例如轮廓增强、鼻窦移植和引导骨再生，这些通常与同种异体移植物（例如人冻干同种异体骨移植物[FDBA]）结合使用和人脱矿冻干同种异体骨移植物 [DFDBAs]）。因此，许多临床医生主张对各种移植手术采用不同的 50/50 或 70/30 比例的同种异体移植/异种移植组合方法。有趣的是，许多临床医生认为异种移植物不可吸收或替代率低的主要原因之一与其外来动物来源有关。最近的研究表明，在加工过程中进行的烧结技术和加热改变了羟基磷灰石的溶解速率，导致破骨细胞不再能够再吸收（溶解）烧结骨的状态。虽然许多临床医生经常将不可吸收的异种移植物与同种异体移植物的骨诱导特性结合起来进行各种骨增量手术，但临床医生由于其来源而被迫使用两种单独的产品（FDA/CE 不允许将同种异体移植物与异种移植物混合使用）相同的盘子/瓶子）。 这使得在了解不同烧结温度变化下异种移植物的溶解速率方面取得了重大进展，从而导致了在与不可吸收异种移植物相似的温度下烧结的不可吸收同种异体骨移植物的突破性发展。不可吸收的同种异体骨移植物的优点在于，它们现在可以与标准同种异体移植物结合以创建结合同种异体移植物和异种移植物的优点的单一混合物，同时允许购买和使用单一产品。这篇评论文章提出了这一概念，并提供了来自 52 周猴子研究的证据，该研究表明几乎没有吸收，以及支持这项新技术作为具有优化骨移植材料特性的“下一代”生物材料的体外数据。