根管治疗难度评估系统及根管充填材料的研究现状

背景:根管充填材料的选择影响根管充填的质量,根管充填质量是影响根管治疗远期疗效的重要因素。目的:综述目前国内外根管治疗难度评估和根管材料的研究现状。方法:由第一作者检索1990/2011 PubMed数据及维普中文科技期刊数据库有关根管治疗难度的危险因素及根管充填材料对根管治疗质量影响等方面的文献。结果与结论:根管治疗是保留患有牙髓根尖周病最有效方法,但治疗效果受诸多因素影响,因此在根管治疗前有必要进行根管治疗难度评估。对于根管治疗难度大的需要先进的治疗器械为根管充填操作技术打下良好基础。根管充填是根管治疗的关键步骤,充填效果直接影响根管治疗的疗效和预后。根管充填不严密会导致微渗漏的发生,根管再次感染使治疗失败。因此,根管治疗的成败很大程度上取决于根管充填的严密与否,而根管充填材料的性能是根管封闭的关键。因此,根管充填材料的选择对根管治疗的成败有很大影响。目前还没有一种根管材料可以完全封闭根管系统,未来的研究需要进一步完善根管治疗难度评估系统及研究理想的新型填充材料。

Metal chelate affinity to immobilize horseradish peroxidase on functionalized agarose/CNTs composites for the detection of catechol

The paper reports a novel amperometric biosensor for catechol based on immobilization of a highly sensitive horseradish peroxidase by affinity interactions on metal chelate-functionalized agarose/carbon nanotubes composites. Metal chelate affinity takes advantage of the affinity of Ni2＋ ions to bind strongly and reversibly to histidine or cysteine tails found on the surface of the horseradish peroxidase. Thus, enzymes with such residues in their molecules can be easily attached to functionalized aga- rose/carbon nanotubes composites support containing a nickel chelate. Linear sweep voltammograms and amperometry are used to study the proposed electrochemical biosensor. Catechol is determined by direct reduction of biocatalytically liberated quinone species at -0.05 V （vs. SCE）. The effect ofpH, applied electrode potential and the concentration of H2O2 on the sensitivity of the biosensor has been investigated. The performance of the proposed biosensor is tested using four different phenolic compounds, showing very high sensitivity, in particular, the linearity of cateehol is observed from 2.0 × 10-8 to 1.05×10-5 M with a detection limit of 5.0×10-9 M.