Denry Isabelle, Holloway Julie A
The University of Iowa College of Dentistry, Department of Prosthodontics & Dows Institute for Dental Research, Iowa City, IA, USA.
The University of Iowa College of Dentistry, Department of Prosthodontics & Dows Institute for Dental Research, Iowa City, IA, USA.
Dent Mater. 2014 Feb;30(2):112-21. doi: 10.1016/j.dental.2013.10.009. Epub 2013 Nov 16.
Fluorapatite glass-ceramics have been shown to be excellent candidates as scaffold materials for bone grafts, however, scaffold production by sintering is hindered by concurrent crystallization of the glass. Objective, our goal was to investigate the effect of Ca/Al ratio on the sintering behavior of Nb-doped fluorapatite-based glasses in the SiO2-Al2O3-P2O5-MgO-Na2O-K2O-CaO-CaF2 system. Methods, glass compositions with Ca/Al ratio of 1 (A), 2 (B), 4 (C) and 19 (D) were prepared by twice melting at 1525°C for 3h. Glasses were either cast as cylindrical ingots or ground into powders. Disk-shaped specimens were prepared by either sectioning from the ingots or powder-compacting in a mold, followed by heat treatment at temperatures ranging between 700 and 1050°C for 1h. The density was measured on both sintered specimens and heat treated discs as controls. The degree of sintering was determined from these measurements. Results and Significance XRD showed that fluorapatite crystallized in all glass-ceramics. A high degree of sintering was achieved at 775°C for glass-ceramic D (98.99±0.04%), and 900°C for glass-ceramic C (91.31±0.10). Glass-ceramics A or B were only partially sintered at 1000°C (63.6±0.8% and 74.1±1.5%, respectively). SEM revealed a unique microstructure of micron-sized spherulitic fluorapatite crystals in glass-ceramics C and D. Increasing the Ca/Al ratio promoted low temperature sintering of fluorapatite glass-ceramics, which are traditionally difficult to sinter.
氟磷灰石微晶玻璃已被证明是骨移植支架材料的理想候选者，然而，玻璃的同时结晶阻碍了通过烧结生产支架。目的，我们的目标是研究Ca/Al比在SiO2-Al2O3-P2O5-MgO-Na2O-K2O-CaO-CaF2系统中对Nb掺杂氟磷灰石基玻璃烧结行为的影响。方法，通过在1525°C下两次熔融3小时制备Ca/Al比为1（A）、2（B）、4（C）和19（D）的玻璃组合物。玻璃要么铸造成圆柱形锭块，要么研磨成粉末。通过从锭块上切片或在模具中粉末压制制备盘形试样，然后在700至1050°C的温度下热处理1小时。测量烧结试样和作为对照的热处理圆盘的密度。根据这些测量确定烧结程度。结果与意义XRD表明所有微晶玻璃中都结晶出氟磷灰石。玻璃陶瓷D在775°C时实现了高度烧结（98.99±0.04%），玻璃陶瓷C在900°C时实现了高度烧结（91.31±0.10）。玻璃陶瓷A或B在1000°C时仅部分烧结（分别为63.6±0.8%和74.1±1.5%）。SEM显示玻璃陶瓷C和D中存在微米级球晶状氟磷灰石晶体的独特微观结构。增加Ca/Al比促进了传统上难以烧结的氟磷灰石微晶玻璃的低温烧结。
