单相氟磷灰石微晶玻璃晶相特征和生物相容性研究

Crystallization and Biocompatibility of Single-phase Fluorapatite Glass-Ceramics

采用熔融-淬火-烧结法制备氟磷灰石微晶玻璃,研究其析晶机制和体外生物相容性。采用X射线衍射(XRD)和场发射扫描电镜(FE-SEM)分析了不同烧结温度下样品的晶相组成和微观结构,利用能量色散X射线光谱仪(EDS)分析了化学成分。结果表明,氟磷灰石是烧结微晶玻璃中的唯一晶相,其晶体可以在较宽的温度范围内析出。显微组织结构致密,显微硬度为644～709 Hv0. 1。氟磷灰石晶体在FE-SEM中有针状和多边形两种形态,多边形是短棒状晶体的横断面。低温下,以固相烧结为主,氟磷灰石析晶以表面析晶为主,晶体生长为针形;高温下玻璃液较多,在保温和冷却凝固过程中析出短棒状晶。在37℃温度下将样品在模拟体液中浸泡14 d,SEM/EDS和FT-IR检测结果表明,样品表面包含磷酸根和羟基的吸收带,形成了羟基磷灰石层,可作为骨或牙齿修复材料。

The crystallization mechanism and in vitro biocompatibility of fluorapatite glass-ceramics prepared by melting-quenching-sintering method were investigated. Phase compositions and the microstructure of the studied samples at different heat treatment temperatures were analyzed by X-ray diffraction (XRD) and field emission-scanning electron microscopy(FE-SEM). Chemical composition was observed and analyzed by energy dispersive X-ray spect-roscopy(EDS). The results show that fluorapatite is the only crystalline phase in the sintered glass-ceramics, and the crystals can be precipitated from the basic glass in relatively wide temperature range. Its microstructure is dense, and Hv0.1 value is between 644 and 709. The crystal morphology of fluorapatites exhibit two kinds of crystal structure: needle-like and polygonal shapes. The polygon is a cross section of a short columnar crystal. The fluorapatite precipitation follows the surface crystallization mechanism in the solid phase sintering process of low temperature. The columnar fluorapatite precipitate from the liquid phase in the sintering process of holding and cooling. The biocompatibility of crystalline materials was inspected in vitro by immersion in simulated body fluid (SBF) for 14 d at 37 ℃. In vitro bioactivity research indicated the formation of hydroxyapatite layer on the surface of the samples. This was confirmed by SEM, EDS photographs and FT-IR. It is expected to be used as a bone or dental restoration materials.