Dental implant placement frequently requires preceding bone augmentation, for example, with hydroxyapatite (HA) or β-tricalcium phosphate (β-TCP) granules. However, HA is degraded very slowly and for β-TCP inconsistent degradation profiles from too rapid to rather slow are reported. To shorten the healing time before implant placement, rapidly resorbing synthetic materials are of great interest. In this study, we investigated the potential of magnesium phosphates in granular form as bone replacement materials. Spherical granules of four different materials were prepared via an emulsion process and investigated in trabecular bone defects in sheep: struvite (MgNHPO·6HO), K-struvite (MgKPO·6HO), farringtonite (Mg(PO)) and β-TCP. All materials except K-struvite exhibited promising support of bone regeneration, biomechanical properties and degradation. Struvite and β-TCP granules degraded at a similar rate, with a relative granules area of 29% and 30% of the defect area 4 months after implantation, respectively, whereas 18% was found for farringtonite. Only the K-struvite granules degraded too rapidly, with a relative granules area of 2% remaining, resulting in initial fibrous tissue formation and intermediate impairment of biomechanical properties. We demonstrated that the magnesium phosphates struvite and farringtonite have a comparable or even improved degradation behavior compared to β-TCP. This emphasizes that magnesium phosphates may be a promising alternative to established calcium phosphate bone substitute materials.

中文翻译：

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使用具有定制降解特性的磷酸镁颗粒改善骨缺损愈合

牙种植体植入通常需要预先进行骨增量，例如使用羟基磷灰石 (HA) 或 β-磷酸三钙 (β-TCP) 颗粒。然而，HA 的降解非常缓慢，并且对于 β-TCP，报告的降解曲线从太快到相当慢不一致。为了缩短种植体植入前的愈合时间，快速吸收的合成材料引起了人们的极大兴趣。在这项研究中，我们研究了颗粒状磷酸镁作为骨替代材料的潜力。通过乳液工艺制备了四种不同材料的球形颗粒，并在绵羊骨小梁缺损中进行了研究：鸟粪石（MgNHPO·6HO）、K-鸟粪石（MgKPO·6HO）、粉红石（Mg（PO））和β-TCP。除钾鸟粪石外的所有材料都表现出对骨再生、生物力学特性和降解的良好支持。鸟粪石和 β-TCP 颗粒以相似的速率降解，植入后 4 个月，相对颗粒面积分别占缺损面积的 29% 和 30%，而法菱石为 18%。只有钾鸟粪石颗粒降解过快，相对颗粒面积剩余 2%，导致最初形成纤维组织，中间损害生物力学性能。我们证明，与 β-TCP 相比，磷酸镁鸟粪石和法菱石具有相当甚至改进的降解行为。这强调磷酸镁可能是现有磷酸钙骨替代材料的有前途的替代品。