Khoshzaban Ahad, Rakhshan Vahid, Najafi Farhood, Aghajanpour Leila, Hashemian Seyed Jafar, Keshel Saeed Heidari, Watanabe Ikuya, Valanezhad Alireza, Jafarzadeh Kashi Tahereh Sadat
Dental Biomaterials Department, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran; Stem Cell Preparation Unit, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran; Iranian Tissue Bank and Research Center, Imam Khomeini Medical Complex Hospital, Tehran University of Medical Sciences, Tehran, Iran.
Iranian Tissue Bank and Research Center, Imam Khomeini Medical Complex Hospital, Tehran University of Medical Sciences, Tehran, Iran.
Mater Sci Eng C Mater Biol Appl. 2017 Aug 1;77:142-150. doi: 10.1016/j.msec.2017.03.183. Epub 2017 Mar 27.
Hydroxyapatite (HA) is a proper scaffold for bone repair, however, it is not of excellent mechanical properties. Most previous studies on the effect of temperature increases were in vitro and had assessed merely improvements of HA's physicomechanical quality. This in vitro/vivo study investigated the effect of temperature increases from 870 to 920°C on physicomechanical and biological quality of Nano-HA. Forty experimentally produced HA disks sintered at 870 to 920°C were prepared (n=20×2). Disks were subjected to Vickers microindentation test (1 disk from each group divided into 4 quarters), Fourier transform infrared spectroscopy (1 disk), X-ray diffraction (XRD) [1 disk together with non-sintered HA], field emission scanning electron microscopy (FSEM, 1 disk from each group together with non-sintered HA), cell seeding and SEM assessment (2 disks), MTT assay over 4 different time periods (16 quadrants of 4 disks from each group), 6 one-thirds of 2 disks from each group for immunocytochemical (ICC) assay, and 8 disks from each group [as well as non-sintered HA] for the animal study (implantation in 4 sockets in 8 rabbits [32 specimens], histomorphometry, and computerized tomography) over two time periods. Quantitative data were analyzed statistically (α=0.05). Vickers microhardness increased from 63.7±11.9 in the 870 group to 153.4±104.7 in the 920 group (P=0.057). XRD indicated more regular crystal patterns in sintered groups compared to non-sintered nanoHA. FSEM showed larger crystals in the 920 group compared to 870 and non-sintered nanoHA. Expression of osteocalcin, osteonectin, and RUNX2 genes were more visible in ICC samples of the 920HA group. In MTT, cell numbers increased in all groups significantly (P=0.000), with no between-group differences (P>0.3). In rabbit experiments, the extent of 'newly formed bone' increased significantly over time (two-way ANOVA, P=0.000), reaching 39.5%, 46.4%, and 77.5% in the groups non-sintered HA, 870, and 920, respectively. The 920°C-sintered nanoHA induced the highest bone formation (P=0.000). Increasing the temperature of nanoHA sintering from 870 to 920°C can improve its physicomechanical properties and bone formation potential.
羟基磷灰石（HA）是一种适合用于骨修复的支架材料，然而，它的机械性能并不出色。此前大多数关于温度升高影响的研究都是在体外进行的，且仅评估了HA物理机械性能的改善情况。这项体外/体内研究调查了870至920°C温度升高对纳米HA物理机械和生物学质量的影响。制备了40个在870至920°C烧结的实验性HA盘（n = 20×2）。对这些盘进行维氏显微硬度测试（每组1个盘，分成4个象限）、傅里叶变换红外光谱分析（1个盘）、X射线衍射（XRD）[1个盘与未烧结的HA一起]、场发射扫描电子显微镜（FSEM，每组1个盘与未烧结的HA一起）、细胞接种和SEM评估（2个盘）、在4个不同时间段进行MTT分析（每组4个盘的16个象限）、每组2个盘中的6个三分之一用于免疫细胞化学（ICC）分析，以及每组8个盘[以及未烧结的HA]用于动物研究（植入8只兔子的4个牙槽窝中[32个标本]、组织形态计量学和计算机断层扫描），分两个时间段进行。对定量数据进行统计学分析（α = 0.05）。维氏显微硬度从870组的63.7±11.9增加到920组的153.4±104.7（P = 0.057）。XRD表明，与未烧结的纳米HA相比，烧结组的晶体模式更规则。FSEM显示，与870组和未烧结的纳米HA相比，920组的晶体更大。在920HA组的ICC样本中，骨钙素、骨连接蛋白和RUNX2基因的表达更明显。在MTT分析中，所有组的细胞数量均显著增加（P = 0.000），组间无差异（P>0.3）。在兔子实验中，“新形成骨”的范围随时间显著增加（双向方差分析，P = 0.000），在未烧结HA组、870组和920组中分别达到39.5%、46.4%和77.5%。920°C烧结的纳米HA诱导的骨形成最高（P = 0.000）。将纳米HA烧结温度从870°C提高到920°C可改善其物理机械性能和骨形成潜力。
