Lee Raymond, Chan Kenneth H, Jew Jamison, Simon Jacob C, Fried Daniel
University of California, San Francisco, San Francisco, CA 94143-0758.
Proc SPIE Int Soc Opt Eng. 2017 Jan 28;10044. doi: 10.1117/12.2256739. Epub 2017 Feb 8.
Both laser irradiation and fluoride treatment alone are known to provide increased resistance to acid dissolution. CO lasers tuned to a wavelength of 9.3 μm can be used to efficiently convert the carbonated hydroxyapatite of enamel to a much more acid resistant purer phase hydroxyapatite (HAP). Further studies have shown that fluoride application to HAP yields fluoroapatite (FAP) which is even more resistant against acid dissolution. Previous studies show that CO lasers and fluoride treatments interact synergistically to provide significantly higher protection than either method alone, but the mechanism of interaction has not been elucidated. We recently observed the formation of microcracks or a "crazed" zone in the irradiated region that is resistant to demineralization using high-resolution microscopy. The microcracks are formed due to the slight contraction of enamel due to transformation of carbonated hydroxyapatite to the more acid resistant pure phase hydroxyapatite (HAP) that has a smaller lattice. In this study, we test the hypothesis that these small cracks will provide greater adhesion for topical fluoride for greater protection against acid demineralization.
已知单独的激光照射和氟化物处理都能增强对酸溶解的抵抗力。调谐到9.3μm波长的CO激光可用于有效地将牙釉质的碳酸羟基磷灰石转化为更耐酸的纯相羟基磷灰石（HAP）。进一步的研究表明，将氟化物应用于HAP会产生更耐酸溶解的氟磷灰石（FAP）。先前的研究表明，CO激光和氟化物处理具有协同作用，能提供比单独使用任何一种方法都显著更高的保护，但相互作用的机制尚未阐明。我们最近使用高分辨率显微镜观察到，在照射区域形成了抗脱矿的微裂纹或“龟裂”区。微裂纹是由于碳酸羟基磷灰石转变为晶格较小、更耐酸的纯相羟基磷灰石（HAP）时牙釉质轻微收缩而形成的。在本研究中，我们检验了这样一个假设，即这些小裂纹将为局部氟化物提供更大的附着力，以更好地防止酸脱矿。
