南方医科大学学报

南方医科大学学报 ›› 2020, Vol. 40 ›› Issue (09): 1307-1312.doi: 10.12122/j.issn.1673-4254.2020.09.13

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纳米羟基磷灰石对牙本质表面矿化及吸附铅离子的作用

杨剑珍，元佩燕，刘成霞，刘 萍，宁晖丽，徐平平   

  • 出版日期:2020-09-20 发布日期:2020-09-20

Effect of nanohydroxyapatite on surface mineralization in acid-etched dentinal tubules and adsorption of lead ions

  • Online:2020-09-20 Published:2020-09-20

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摘要： 目的 研究纳米羟基磷灰石（nHA）对脱矿牙本质小管的表面矿化作用及对模拟污水中铅离子的吸附作用。方法 选择牙冠完好无损、新鲜拔除的前磨牙和磨牙制作离体牙本质片各30个，使用10%的枸橼酸酸蚀处理牙本质片2 min，建立小管开放的牙本质敏感模型。脱矿牙本质片用随机数字表法分组，10片/组。空白对照组：蒸馏水刷洗；HA组：0.2 g HA刷洗；n HA组：0.2 g n HA 刷洗。每天早晚分别用蒸馏水、0.2 g HA 和 0.2 g nHA刷洗牙本质片表面2 min，连续7 d，表面处理后扫描电镜（SEM）观察牙本质片表面情况，能谱仪（EDS）分析钙、磷原子百分比并采用SPSS20.0软件进行统计学分析。配制系列浓度的HA悬液和nHA悬液，分别取1 mL与50 mL初始浓度为1 mg/L的铅离子溶液反应24 h，电感耦合等离子发射光谱仪（ICP）测定上清液中铅离子浓度，计算铅离子吸附率及吸附能力。结果 扫描电镜下空白对照组的牙本质片表面光滑，牙本质小管空虚。HA组的牙本质片表面为块状颗粒物覆盖，附着疏通，管径缩小。nHA组的表面堵塞物细腻、均质，附着紧密，牙本质小管管径明显缩小。经HA刷洗后可显著增加牙本质片表面钙、磷原子百分比，增加量为：nHA组>HA组>空白对照组（P<0.000），差异具有统计学意义。在本实验的浓度范围内，HA对铅离子的吸附随浓度升高而下降，最高附率达83.01%，nHA对铅离子的吸附率随着浓度升高先升高后达吸附平衡，吸附率高达98.79%。并发现HA对铅离子的吸附能力倍数与其浓度倍数呈良好的线性相关关系。结论 nHA较普通HA具有更好的脱矿牙本质表面矿化能力和铅离子吸附能力。

关键词: 纳米羟基磷灰石, 牙本质过敏症, 表面矿化, 铅离子, 吸附

Abstract: Objective To study the effect of nanohydroxyapatite (nHA) for promoting surface mineralization of demineralized dentin discs and adsorption of lead ions in simulated sewage water. Methods Sixty dentin disks were prepared from freshly extracted teeth with intact crown (including 30 premolars and 30 molars) and treated with 10% citric acid for 2 min to simulate dentinal tubules with dentin hypersensitivity. The etched dentin discs were brushed with distilled water, 0.2 g HA or 0.2 g nHA for 2 min twice a day for 7 consecutive days, after which scanning electron microscopy (SEM) was performed and calcium and phosphorus contents in the dentin discs were detected using EDS. Lead ion adsorption capacities of HA and nHA were tested by mixing 1 mL serial concentrations of HA and nHA suspensions with 50 mL lead ion solutions (1.0 mg/L). After 24 h, the residual lead ion concentration in the supernatant was measured using ICP to calculate lead ion adsorption rate and adsorption capacity of the materials. Results SEM showed a smooth surface and empty dentin tubules in the acid- etched dentin dics. The dentin dics treated with HA were covered with masses of particles that loosely attached to the surface, and the diameter of the dentin tubules was reduced. In nHA group, the dentin discs showed a fine and homogeneous surface clogging with a tight attachment, and the dentin tubule diameter was obviously reduced. Daily brushing with HA and nHA, especially the latter, significantly increased calcium and phosphorus contents on the surface of the dentin dics (P<0.000). In lead ion adsorption experiment, the lead ion adsorption rate of HA decreased as its concentration increased with the highest adsorption rate of 83.01%; the adsorption rate of nHA increased with its concentration until the adsorption equilibrium was reached, and its highest adsorption rate was 98.79%. A good liner relationship was found between the adsorption ability and concentration of HA. Conclusion Compared with HA, nHA has a better capacity for surface mineralization of acid-etched dentin discs and also a better ability of lead ion adsorption.

Key words: nanohydroxyapatite, dentin hypersensitivity, surface mineralization, lead ions, adsorption