Laboratory of Biomaterials and Oral Pathology, Dental School, Department of Biomedical and NeuroMotor Sciences, University of Bologna, Bologna, Italy; Endodontic Clinical Section, Dental School, Department of Biomedical and NeuroMotor Sciences, University of Bologna, Bologna, Italy.
Department of Medical, Oral and Biotechnological Sciences, University of Chieti-Pescara, Chieti Scalo, Italy.
Dent Mater. 2017 May;33(5):e221-e238. doi: 10.1016/j.dental.2017.01.017. Epub 2017 Feb 21.
To study the in vivo osteoinductive potential, bone-bonding ability (bioactivity) and bone biomineralization of current hydraulic calcium silicate cements used as graft materials and placed in contact with medullary bone.
ProRoot MTA, MTA Plus and Biodentine were used to fill surgical bone defects (2-mm diameter through the entire cortical thickness to reach the medullary bone) in the tibia of mature male rabbits. Tibiae were retrieved after 30days and submitted to histological analysis and microchemical characterization using Optical Microscopy (OM) and Environmental Scanning Electron Microscopy with Energy Dispersive X-ray analysis (ESEM-EDX). Bone neoformation and histomorphometric evaluations, degree of mineralization (by Ca/P, Ca/N and P/N ratios) and the diffusion of material elements were studied.
Bone neoformation was observed in response to all materials. No sign of necrosis were found on the walls of the pre-existing cortical bone. No osteoclasts and no formation of fibrous tissue were evident. Sign of angiogenesis were present. EDX (element content, line profile and element mapping) showed the increase in Ca and P and decrease in C, S and N from the mature bone towards the mineralizing interface. Ca/P, Ca/N and P/N ratios showed differences in the degree of mineralization/maturation stage of bone. MTA Plus and ProRoot MTA exhibited close contact with the pre-existing bone and good bone-bonding with neoformed bone juxtaposed on the medullary side of the materials without interposed connective tissue or resorption lacunae or gaps. The materials showed a dense appearance with 100% of residual materials and no colonization by fluids and cells. No migration of Bi or Al material elements to the newly formed bone was found. Biodentine showed newly formed trabecular bone with marrow spaces and sparse traces of residual material (≈9%).
The in vivo osteoinductive properties with dynamic biomineralization processes around these calcium silicate materials extruded in medullary bone in appropriate animal model have been demonstrated by ESEM-EDX in association with OM. Good biocompatibility was evident as only slight inflammatory infiltrate and no sign of necrosis at the interface with the pre-existing bone were found. MTA Plus and ProRoot MTA exhibited bioactive potential as they can bond to bone directly without interposed connective tissue. Biodentine was replaced by newly formed bone.
The results of the study demonstrate the capacity of calcium silicate cements to allow osteoid matrix deposition by activated osteoblasts and favour its biomineralization, and to achieve a direct bond between the (bioactive) materials surface and the mineralized bone matrix.
研究当前用作移植物并与髓腔骨接触的水合硅酸钙水泥的体内成骨潜力、骨结合能力（生物活性）和骨生物矿化能力。
将 ProRoot MTA、MTA Plus 和 Biodentine 用于填充成熟雄性兔胫骨中的外科骨缺损（通过整个皮质厚度的 2mm 直径到达髓腔骨）。30 天后取出胫骨，并通过光学显微镜（OM）和环境扫描电子显微镜与能量色散 X 射线分析（ESEM-EDX）进行组织学分析和微观化学表征。研究了新骨形成和组织形态计量学评估、矿化程度（通过 Ca/P、Ca/N 和 P/N 比值）以及材料元素的扩散。
所有材料均观察到新骨形成。未在原有皮质骨壁上发现坏死迹象。没有破骨细胞，也没有纤维组织形成。有血管生成的迹象。EDX（元素含量、线轮廓和元素映射）显示，从成熟骨向矿化界面，Ca 和 P 增加，C、S 和 N 减少。Ca/P、Ca/N 和 P/N 比值显示出骨矿化/成熟阶段程度的差异。MTA Plus 和 ProRoot MTA 与原有骨紧密接触，与髓腔侧的新形成骨良好结合，没有插入的结缔组织或吸收陷窝或间隙。材料呈致密外观，残留材料 100%，无液体和细胞定植。未发现 Bi 或 Al 材料元素向新形成的骨迁移。Biodentine 显示出有骨髓腔的新形成的小梁骨和稀疏的残留材料痕迹（≈9%）。
通过 ESEM-EDX 与 OM 结合，在适当的动物模型中证明了这些在髓腔骨中挤出的硅酸钙材料具有体内成骨诱导特性和动态生物矿化过程。良好的生物相容性明显，因为仅在与原有骨的界面处发现轻微的炎症浸润和无坏死迹象。MTA Plus 和 ProRoot MTA 表现出生物活性潜力，因为它们可以直接与骨结合，而没有插入的结缔组织。Biodentine 被新形成的骨取代。
研究结果表明，硅酸钙水泥能够允许激活的成骨细胞沉积类骨质基质并促进其生物矿化，并在（生物活性）材料表面和矿化骨基质之间实现直接结合。
