E)光动力学疗法处理
表2A–E:Ti合金样品表面局部区域组成的EDS分析数据,其中Kα为X射线测量值,σ为%wt浓度数据的标准偏差:A)对照样品;B)碳酸氢盐喷射抛光样品;C)四环素处理样品;D)超声处理样品;E)光动力学疗法处理样品。
粗糙度结果
粗糙度分析侧重于以CM获得的Ti合金样品数据,CM可测定三个重要的3D粗糙度参数值: Sa、Sq及Sdar。这些数据示于下文表3。
值 | 对照 | 超声波 | 光动力学 | 碳酸氢盐 | 四环素 |
Sa(µm) | 1.86 | 0.79 | 1.86 | 1.82 | 1.53 |
Sq(µm) | 2.42 | 1.13 | 2.44 | 2.34 | 1.99 |
Sdar(%) | 20.51 | 5.03 | 23.10 | 20.46 | 15.99 |
表3:以共聚焦显微镜获得的Ti合金样品表面粗糙度数据。分析侧重于3个粗糙度值:Sa(高度算术平均值);Sq(高度均方根[rms]);Sdar(展开面积/投影面积)。
首先,光动力学疗法处理、四环素处理和碳酸氢盐喷射抛光样品的Sa和Sq粗糙度值与对照样品的几乎相同。其次,超声处理样品的Sa和Sq粗糙度值比对照样品的小30%~50%。Sdar粗糙度值显示类似的趋势,不过喷射抛光和四环素处理样品的Sdar值明显小于对照样品(参见以下图5)。
图5:表3中Ti合金种植体样品表面粗糙度数据Sa(蓝色)、Sq(红色)和Sdar(绿色)的曲线图,数据从CM 3D形貌图像获取。曲线图显示每种样品表面粗糙度值的变化程度。
对拍摄于对照样品(未改性)两处不同区域的AFM图像进行初步分析,结果表明,如果表面非常粗糙,其不同小区域的粗糙度值可能差异较大,因此AFM并非用于大面积测量的实用技术,而本研究的这类样品需要这种测量。
粗糙度值 | 对照样品区域1 | 对照样品区域2 |
Sa(µm) | 0.18 | 0.14 |
Sq(µm) | 0.170 | 0.125 |
Sdar(%) | 36.80 | 40.10 |
表4:以原子力显微镜获取的Ti合金种植体对照样品区域2表面粗糙度数据。分析侧重于3个粗糙度值:Sa(高度算术平均值);Sq(高度均方根[rms]);Sdar(展开面积/投影面积)。
如上文表4所示,两个区域的Sdar值相差约10%,Sq值相差约35%,Sa值相差约30%。另一方面,AFM图像显示z范围差值超过1µm的峰和山,这对于AFM分析而言属于大差异,会导致图像中存在伪影,即可能由于顶端扫描样品时碰触表面而产生的“条纹”。总而言之,AFM图像结果取决于样品形貌和力学性能、反馈回路增益、扫描速率等。
总结和结论
目前临床上使用的Ti合金牙种植体具有各种各样的表面特性(包括结构特征和化学性质)。上述表面改性保留种植体的关键物理性质,只涉及其最外层表面,最终目标为实现所需的生物反应。以上介绍了不同物理化学、物理和化学表面改性方法的优劣。这些方法将帮助我们更好地了解种植体材料表面改性如何影响骨-种植体界面,以及如何在成功治疗种植体周围炎(种植体周围牙质组织感染)后的愈合过程中影响种植体骨整合优化方法的制定。目前尚未完全清楚表面粗糙度和化学性质对骨整合的影响程度。具有最佳临床效果的理想粗糙度仍是个未知数[20–23]。
对于用四环素和光动力学疗法改性的样品,其形态受到钛合金析出的金属间颗粒化学侵蚀的影响。对于用喷射抛光和超声处理改性的样品,机理主要与力学相关。喷射抛光和光动力学疗法处理样品的表面粗糙度与对照样品相似(基于Sa、Sq和Sdar值)。超声和四环素处理样品的表面粗糙度低于对照样品。事实上,超声处理可使表面明显变得平坦。
碳酸氢盐喷射抛光样品的污染程度最大(盐残留),其次为四环素和光动力学疗法处理样品,超声处理样品污染最少。由于接触到盐(碳酸氢盐)或化合物(四环素或甲苯胺蓝),喷射抛光、四环素及光动力学疗法处理的Ti合金样品污染程度最大,这是显而易见的。超声处理的样品与对照样品一样洁净,或比对照样品洁净,不过也存在少量的铁(Fe),这些铁可能来自超声处理所用的钢探头。
可以通过合理使用这些牙科处理方法,最大可能提高种植体周围炎愈合过程Ti合金种植体与骨结合的概率。也许可以先使用光动力学疗法或碳酸氢盐喷射抛光(频率较低,比如20kHz,功率亦较低)维持种植体的表面粗糙度,然后施以短暂轻微的超声处理,或可有效净化表面。
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