再矿化对人牙釉质纳米力学性能和微摩擦学行为的影响

发布时间：2018-04-24 00:23

本文选题：人牙釉质 + 酸蚀　；参考：《西南交通大学》2014年博士论文

【摘要】：人体天然牙是人体内最重要的咀嚼器官,在人的一生中行使重要功能。牙冠最外层的牙釉质是人体内最硬的组织,对咀嚼磨耗具有较好的抵抗力。人体口腔环境十分复杂,除常见的因咀嚼需要产生的机械行为外,牙齿最外层的牙釉质还经常遭受内源性或外源性酸性介质引起的酸蚀,进而诱发牙齿过度磨损。随着酸性饮料摄入量的增大和人类平均寿命的提高,牙齿酸蚀问题日趋严重,酸蚀已经成为现代社会人类牙齿过度磨损的主要诱因。因此,开展人牙釉质酸蚀损伤及再矿化修复行为的系统研究具有非常重要的理论意义和现实意义。本文主要采用纳米压痕/划痕仪,试验研究了体外再矿化对酸蚀人牙釉质纳米力学性能和微摩擦学行为的影响。使用扫描电子显微镜(SEM)、电子能谱仪(EDX)、表面轮廓仪、激光共聚焦扫描显微镜(LCSM)、X射线衍射分析(XRD)等材料表面分析测试设备,对牙釉质的再矿化表面进行了详细的观察和分析。所取得的主要结论如下：(1)在0.001 M柠檬酸介质(pH=3.25)中,当人牙釉质的酸蚀时问不大于10 min时,牙釉质次表层由于酸蚀脱矿形成的软化层厚度为微纳米尺度,约为500～1000 nm。随着酸蚀时间增加,酸蚀的软化层厚度呈现非线性增大。软化层的厚度与牙釉质表面酸蚀损伤程度密切相关,牙釉质表面酸蚀损伤越严重,软化层厚度越大。(2)在人工唾液介质中经过12h体外再矿化处理后,在酸蚀人牙釉质试样表面生成一层与原始人牙釉质成分相似、但生长方向不同的矿化结晶,这层晶体在C轴无明显生长取向。体外再矿化处理后,酸蚀人牙釉质表面的纳米力学性能和微观摩擦学性能均有显著提高,再矿化表面的纳米压痕硬度和弹性模量显著高于酸蚀表面,磨损量明显低于酸蚀表面。但是,再矿化表面的纳米力学性能和微摩擦学性能仍明显低于人牙釉质原始表面,这说明在给定的实验条件下,人牙釉质表面的酸蚀损伤可以通过再矿化得到一定程度的修复,但无法完全修复。(3)CPP-ACP具有修复牙釉质酸蚀损伤的能力。在2.0% w/v CPP-ACP溶液中经12 h体外再矿化处理后,酸蚀人牙釉质表面形成一层不均匀的无定型态矿物沉积,表面矿物质含量、硬度及弹性模量均增大,表面摩擦力、摩擦系数和磨损量均下降。但是,再矿化表面的纳米力学性能和耐磨性仍明显低于牙釉质原始表面。由于无定型态的再矿化沉积物和健康牙釉质的HAP晶体之间存在明显的结构差异,因此,尽管CPP-ACP溶液中钙、磷酸根离子浓度高于人工唾液,但是它对酸蚀人牙釉质表面纳米力学性能和微摩擦学行为的修复依然不彻底。(4)由于化学组成、微观结构和晶体特性的差异,乳牙釉质的酸蚀耐受性较恒牙釉质差,在相同的酸蚀条件下,乳牙釉质的酸蚀损伤重于恒牙釉质。在2.0% w/vCPP-ACP溶液中经过12h的体外再矿化处理后,乳牙釉质表面由于酸蚀导致的形貌损伤、纳米力学性能下降和微摩擦学行为改变均得到了一定程度的修复。鉴于乳牙釉质的酸蚀耐受性较恒牙釉质差,相同酸蚀时间乳牙釉质表面脱矿较恒牙釉质严重,因此,乳牙釉质的再矿化修复作用弱于恒牙釉质。(5)酸蚀时间、再矿化工况和生命活性物质均会影响牙釉质表面酸蚀损伤的再矿化修复。酸蚀时间越短,牙釉质的再矿化表面越平整,再矿化沉积物的分布越均匀致密。搅拌不利于酸蚀牙釉质的再矿化修复,和静止工况相比,搅拌工况下酸蚀牙釉质再矿化表面的再矿化沉积物排列疏松,分布不均匀,脱矿导致的蜂窝结构仍然隐约可见。延长酸蚀人牙釉质在人工唾液介质中的再矿化处理时间,有助于再矿化表面生成排列有序的片状HAP晶体。人体天然全唾液中的蛋白等有机物对酸蚀人牙釉质的再矿化修复存在诱导和促进作用,和人工唾液介质相比,酸蚀牙釉质在人体天然全唾液介质中再矿化处理12h后,再矿化表面生成的晶体更均匀,排列更整齐,表面耐磨性较好。
[Abstract]:The human natural tooth is the most important masticatory organ in the human body and plays an important role in the human life. The enamel of the outer layer of the crown is the most hard tissue in the human body and has a good resistance to the chewing wear. The human oral environment is very complex, and the outer enamel of the teeth is also the most common in addition to the mechanical behavior required by chewing. Acid erosion caused by endogenous or exogenous acid medium is often caused by acid corrosion, which induces excessive wear of teeth. With the increase of acid drink intake and the increase of human life expectancy, the problem of dental erosion is becoming more and more serious. Acid erosion has become the main cause of excessive wear of human teeth in modern society. Therefore, the acid erosion damage of human tooth enamel is carried out. The systematic study of remineralization and remineralization is of great theoretical and practical significance. In this paper, the effects of remineralization on the mechanical properties and Microtribological behavior of acid etching human tooth enamel were studied by nano indentation / scratch tester. The scanning electron microscopy (SEM), EDX, surface profilometer were used to study the effect of remineralization in vitro. Laser confocal scanning microscope (LCSM), X ray diffraction analysis (XRD) and other materials surface analysis and testing equipment were used to observe and analyze the enamel remineralized surface in detail. The main conclusions are as follows: (1) the enamel subsurface in the 0.001 M citric acid medium (pH=3.25) when the acid etching of the human tooth enamel is not more than 10 min The thickness of the softening layer formed by the acid erosion demineralization is micro nano scale, which is about 500~1000 nm. with the increase of etching time, the thickness of the softening layer of the acid corrosion increases nonlinear. The thickness of the softening layer is closely related to the degree of acid erosion damage on the enamel surface, the more serious the erosion of the enamel surface, the greater the thickness of the softening layer. (2) artificial saliva. After remineralization of 12h in vitro, a layer of mineralized crystallization similar to the original human tooth enamel was formed on the surface of the enamel on the surface of the acid etching human tooth enamel, with no obvious growth orientation on the C axis. After remineralization, the nanomechanical and Microtribological properties of the acid etching human enamel surface were both. The nano indentation hardness and modulus of elasticity of remineralized surface are significantly higher than that of the acid corrosion surface, and the wear amount is obviously lower than that of the etching surface. However, the nanomechanical properties and Microtribological properties of the remineralized surface are still lower than the original surface of the human tooth enamel, which shows the acid erosion of the enamel surface under the given experimental conditions. The injury can be remineralized to a certain extent, but it can not be repaired completely. (3) CPP-ACP has the ability to repair dental enamel corrosion damage. After remineralizing in 2% w/v CPP-ACP solution by 12 h in vitro, the acid etching enamel surface forms an inhomogeneous amorphous mineral deposit, surface mineral content, hardness and elasticity The modulus increased, the surface friction, the friction coefficient and the wear amount were all decreased. However, the nanomechanical properties and wear resistance of the remineralized surface were still significantly lower than the original surface of the enamel. There was a significant structural difference between the remineralized sediments and the HAP crystals of the healthy enamel. Therefore, the calcium and phosphorus in the CPP-ACP solution The concentration of acid root ion is higher than that of artificial saliva, but it is still not thorough to repair the nanomechanical properties and Microtribological behavior of the enamel surface. (4) the acid corrosion resistance of the deciduous enamel is worse than that of the permanent tooth enamel because of the chemical composition, microstructure and crystal characteristics, and the acid erosion of the enamel of the deciduous teeth under the same etching condition The injury was heavier than the enamel of permanent teeth. After 12h remineralization in 2% w/vCPP-ACP solution, the surface of the enamel surface was damaged by acid erosion, the decline of nanomechanical properties and the change of Microtribological behavior were repaired to a certain extent. The demineralization of enamel surface is more serious than that of the permanent tooth enamel. Therefore, the remineralization repair effect of the enamel of the deciduous teeth is weaker than that of the permanent enamel. (5) the time of etching, the remineralization condition and the life active substance will affect the remineralization of the enamel surface erosion damage. The shorter the time of the etching, the more smooth the remineralized surface of the enamel is, the distribution of the remineralized sediment The more uniform and compact, the agitation is not conducive to the remineralization of the enamel of acid etching. Compared with the static condition, the remineralized sediments on the enamel remineralized surface under the stirring condition are loosely arranged and the distribution is uneven, and the honeycomb structure caused by demineralization is still invisible. Inter mineralized surface contributes to the formation of ordered lamellar HAP crystals. The protein and other organic compounds in human natural whole saliva induce and promote the remineralization of the acid etching human enamel. Compared with the artificial saliva medium, the acid etching enamel remineralized 12h in the human natural whole saliva and remineralized the surface. The crystals are more uniform, arranged more orderly and have better surface wear resistance.

【学位授予单位】：西南交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R783

【参考文献】