Rodde J, Duprez J P
Bull Group Int Rech Sci Stomatol Odontol. 1991 Sep;34(2):95-105.
Crystal formation may occur during etching of enamel surfaces with phosphoric acid. In this in vitro study we observed, from a morphological standpoint, some crystals left after etching, on the surfaces, using the scanning electron microscope. More often, after water-spraying, a thin generalized precipitate remains on the surface. This precipitate may be harmful for the retention of composite resins. On few specimens we obtained needle-shaped or petal-like crystals. Crystal deposits were spread evenly, on the surface, or nucleated from different points. We tempted to identify these crystal formations by X-ray diffraction and microprobe analysis. Chemical identification seems very important because calcium phosphates solubility varies. Crystal dissolution in saliva can lead to marginal leakage and impairs the quality of esthetic restorations. On the contrary insoluble crystals may ensure microscopic retentions and crystal growth is now considered as an alternative for enamel pretreatment in bracket bonding. Crystal formation, in these first experiments, is too scarce to be used for crystal bonding. But it appears that two factors may enhance the crystal number: a preliminary topical application of fluoride and adsorption of an acidic protein, on the surface, before etching. However, further investigations are still necessary.
用磷酸蚀刻牙釉质表面时可能会发生晶体形成。在这项体外研究中，我们从形态学角度，使用扫描电子显微镜观察了蚀刻后留在表面的一些晶体。更常见的是，喷水后，表面会残留一层薄薄的普遍沉淀物。这种沉淀物可能对复合树脂的固位有害。在少数标本上，我们获得了针状或花瓣状晶体。晶体沉积物在表面均匀分布，或从不同点成核。我们试图通过X射线衍射和微探针分析来鉴定这些晶体形成。化学鉴定似乎非常重要，因为磷酸钙的溶解度各不相同。晶体在唾液中的溶解会导致边缘渗漏，并损害美观修复体的质量。相反，不溶性晶体可能确保微观固位，现在晶体生长被认为是托槽粘结中牙釉质预处理的一种替代方法。在这些初步实验中，晶体形成太少，无法用于晶体粘结。但似乎有两个因素可能会增加晶体数量：蚀刻前在表面预先局部应用氟化物和吸附一种酸性蛋白质。然而，仍需要进一步研究。
